Category 6™

Vance Forms in the Eastern Pacific; the Atlantic Goes Quiet

By: JeffMasters, 3:05 PM GMT on October 31, 2014

Tropical Storm Vance formed in the Eastern Pacific on Thursday afternoon. Satellite images show that Vance is struggling with dry air and wind shear, with just a modest area of heavy thunderstorms that had not improved in organization since Thursday. By Saturday, the wind shear should relent, allowing intensification into a Category 1 hurricane by Sunday. The storm's heaviest rains will remain well offshore from Mexico through Sunday, but our two top models for predicting hurricane tracks--the GFS and European models--forecast that Vance will get pulled to the northeast by a trough of low pressure early next week, and make landfall in Mainland Mexico northwest of Puerto Vallarta on Tuesday night. The 8 am EDT Friday run of the SHIPS model predicted that wind shear would remain low, 5 - 10 knots, though Monday, then ramp up significantly on Monday night and Tuesday as Vance gets caught up in the trough of low pressure that will sling it into Mexico. The higher wind shear should be able to significantly weaken Vance before landfall, making heavy rain the primary threat. In their 11 am EDT Friday Wind Probability Forecast, NHC gave a 15% chance that Vance would bring tropical storm-force winds of 39+ mph to Puerto Vallarta and the tip of the Baja Peninsula. Vance's moisture will likely bring heavy rain and the threat of flooding to Texas on Wednesday.


Figure 1. VIIRS satellite image of Tropical Storm Vance off the Pacific coast of Mexico on Thursday, October 30, 2014. At the time, Vance had top sustained winds of 40 mph. Image credit: NOAA Visualization Lab.

A near-record active 2014 Eastern Pacific hurricane season
Vance's formation gives the 2014 Eastern Pacific (east of 140°W) 20 named storms, 13 hurricanes, and 8 intense hurricanes in 2014. An average Eastern Pacific hurricane season sees 15 named storms, 8 hurricanes, and 3 intense hurricanes during the entire year. This year is the busiest year since 1992, which set records for total number of named storms (25), hurricanes (14), and intense hurricanes (8). If we include the Central Pacific between 140°W and 180°W, these record tallies in 1992 were 28 named storms, 16 hurricanes, and 10 intense hurricanes. The 2014 totals in the combined Eastern and Central Pacific basins so far are 21 named storms, 15 hurricanes, and 9 intense hurricanes (Genevieve did not become a hurricane and then major hurricane until it crossed from the Eastern Pacific into the Central Pacific, and Category 1 Hurricane Ana existed only in the Central Pacific, not the Eastern Pacific.) On average, we can expect one more named storm and no hurricanes in the Eastern Pacific in November; I expect we will get 1 - 2 more named storms--Winnie and Xavier--this year, after Vance. The top four busiest years in the Eastern Pacific now stands like this:

1. 1992 - 24 named storms
2. 1985 - 22 named storms
3. 1983 - 21 named storms
4. 2014 - 20 named storms
4. 1990 - 20 named storms

Arabian Sea's Tropical Cyclone Nilofar destroyed by wind shear
In the Arabian Sea between India and Africa, Cyclone Nilofar has been shredded by high wind shear of 50 knots, and the Joint Typhoon Warning Center has issued its last advisory on the system. Nilofar's remnants will bring a few areas of heavy rain to the India/Pakistan border region.


Figure 2. MODIS satellite image of Tropical Cyclone Nilofar in the Arabian Sea on Friday morning, October 31, 2014. At the time, Nilofar was a dissipating tropical storm with 40 mph winds, and the low-level circulation had been exposed to view by high wind shear. Image credit: NASA.

Tropical Storm Nuri forms in Western Pacific
The Western Pacific has become active again, with the formation of Tropical Storm Nuri. Nuri is headed towards Japan, and may pass close enough to Japan next Thursday and Friday to bring them heavy rain.

Quiet in the Atlantic
The Atlantic is quiet today, with no areas of concern to discuss. None of the three reliable models for predicting tropical cyclone genesis predicts any development in the Atlantic over the next five days. With November at hand and El Niño-like atmospheric conditions in place, the odds of getting Tropical Storm Isaias before the end of the Atlantic hurricane season on November 30 are probably around 30%.

Jeff Masters

Hurricane

95L Little Threat; TD 21E a Long-Range Threat to Mexico's Pacific Coast

By: JeffMasters, 3:22 PM GMT on October 30, 2014

An area of disturbed weather (95L) just north of the Virgin Islands is headed northwest at 10 to 15 mph. Satellite loops show that 95L has large, sloppy surface circulation and moderate amount of heavy thunderstorm activity that is mostly disconnected from the center of the storm by high wind shear of 20 - 30 knots. Water vapor satellite images show that 95L has dry air to its west that is likely interfering with development. Sea Surface Temperatures (SSTs) are warm, about 29°C. The 8 am EDT Thursday run of the SHIPS model predicted that wind shear would remain a high 20 - 30 knots through Saturday night, then increase to 30 - 50 knots beginning on Sunday. These high wind shear values make development conditions marginal through Saturday, then almost impossible beginning on Sunday. None of our three reliable models for predicting tropical cyclone genesis predict development of 95L over the next five days. In their 8 am EDT Thursday Tropical Weather Outlook, NHC gave the disturbance 2-day and 5-day development odds of 10%. The only land area at risk from 95L is Bermuda.


Figure 1. MODIS satellite image of Invest 95L to the northeast of Puerto Rico on Wednesday afternoon October 29, 2014. The surface circulation center was exposed to view by high wind shear. Image credit: NASA.

Arabian Sea's Tropical Cyclone Nilofar getting ripped up by wind shear
In the Arabian Sea between India and Africa, Cyclone Nilofar has been shredded by high wind shear of 40 - 50 knots. and was a tropical storm with just 50 mph winds at 10 am EDT Thursday. Even higher levels of wind shear, combined with very dry air from the deserts of the Middle East, should cause Nilofar to dissipate on Friday. Nilofar's remnants will be capable of bringing 1 - 2" of rain over the weekend to the Pakistan/India border region, according to the 2 am EDT Thursday run of the HWRF model.


Figure 2. MODIS satellite image of Tropical Cyclone Nilofar in the Arabian Sea on Thursday morning, October 30, 2014. At the time, Nilofar was a tropical storm with 55 mph winds, and the low-level circulation had been exposed to view by high wind shear. Image credit: NASA.

Tropical Storm Vance forms in the Eastern Pacific
Tropical Storm Vance formed in the Eastern Pacific on Thursday afternoon. Satellite images show that Vance is in the organizing stages, with a small area of heavy thunderstorms, some solidifying low-level spiral bands, and a Central Dense Overcast (CDO) of high cirrus clouds, characteristic of intensifying tropical storms. The storm is over warm SSTs, near 29°C, but some dry air and moderate wind shear are slowing development. By Saturday, these issues should relent, allowing intensification into a Category 1 hurricane by Sunday. The storm's heaviest rains will remain well offshore from Mexico over the next four days, but our two top models for predicting hurricane tracks--the GFS and European models--forecast that Vance will get pulled to the northeast by a trough of low pressure early next week, and make landfall in Mainland Mexico northwest of Puerto Vallarta on Tuesday night. The 8 am EDT Thursday run of the SHIPS model predicted that wind shear would remain low, 5 - 10 knots, though Monday, then ramp up significantly on Monday night and Tuesday as Vance gets caught up in the trough of low pressure that will sling it into Mexico. The higher wind shear should be able to significantly weaken Vance before landfall, making heavy rain the primary threat.

Hurricane expert Steve Gregory has more on the tropics in a Thursday afternoon post.

Jeff Masters

Hurricane

95L No Big Deal; 100 Feared Dead, 300 Missing in Sri Lanka Landslide

By: JeffMasters, 3:05 PM GMT on October 29, 2014

An area of disturbed weather (95L) associated with a tropical wave interacting with an upper level trough of low pressure is a few hundred miles northeast of the northern Lesser Antilles Islands, and is headed northwestward to west-northwestward at 10 to 15 mph. Satellite loops show that 95L has a modest amount of spin and heavy thunderstorm activity, but high wind shear of 25 - 30 knots is keeping the thunderstorms disorganized. Water vapor satellite images show that 95L has dry air to its west that is likely interfering with development. Sea Surface Temperatures (SSTs) are warm, about 29°C. The 8 am EDT Wednesday run of the SHIPS model predicted that wind shear would remain a high 20 - 30 knots through Friday, then increase to 30 - 50 knots Saturday and Sunday. These high wind shear values make development conditions marginal through Friday, then almost impossible beginning on Saturday. None of our three reliable models for predicting tropical cyclone genesis predict development of 95L over the next five days. In their 8 am EDT Wednesday Tropical Weather Outlook, NHC gave the disturbance 2-day and 5-day development odds of 30%. The only land area at risk from 95L is Bermuda.


Figure 1. Latest satellite image of 95L.

Tropical Cyclone Nilofar in Arabian Sea steadily weakening
In the Arabian Sea between India and Africa, Cyclone Nilofar has weakened to a Category 2 storm with 105 mph winds after peaking on Tuesday as the third strongest tropical cyclone on record in the Arabian sea--a Category 4 storm with 130 mph winds. With wind shear a high 30 - 40 knots and expected to increase, plus very dry air from the deserts of the Middle East to its west being driven into its core, rapid weakening and dissipation before landfall is expected.


Figure 2. MODIS satellite image of Tropical Cyclone Nilofar in the Arabian Sea on Wednesday afternoon, October 29, 2014. At the time, Nilofar was a weakening Category 2 storm with 105 mph winds. Image credit: NASA.

Intense hurricanes are rare in the Arabian Sea, due to the basin's small size, the interference of the summer monsoon, and the frequent presence of dry air and dust from the Arabian Peninsula. Nilofar's 130 mph sustained winds on Tuesday made it the third strongest tropical cyclone ever recorded in the Arabian Sea, behind the 165 mph winds of Category 5 Cyclone Gonu of 2007, which devastated Oman, and the 145 mph winds of Category 4 Cyclone Phet of 2010, which also did heavy damage in Oman. Fourth place is held jointly by the 2001 India Cyclone 01A and Very Severe Cyclonic Storm ARB 01 (02A) of 1999, which were Category 3 storms with 125 mph winds.

Eastern Pacific disturbance 93E near tropical depression status
Satellite images show that a well-organized area of disturbed weather with a modest area of heavy thunderstorms in the Eastern Pacific, a few hundred miles southwest of the Mexico/Guatemala border (Invest 93E), is close to tropical depression status. Our top three models for predicting tropical cyclone genesis all develop the system, and in their 8 am EDT Wednesday Tropical Weather Outlook, NHC gave the disturbance 2-day and 5-day odds of development near 100%. The storm's heaviest rains will remain well offshore from Mexico over the next four days, but our two top models for predicting hurricane tracks--the GFS and European models--forecast that 93E will get pulled to the northeast by a trough of low pressure early next week, and make landfall in Mainland Mexico northwest of Puerto Vallarta on Tuesday.


Figure 3. Sri Lankan residents stand near a damaged building at the site of a landslide caused by heavy monsoon rains in Koslanda village in central Sri Lanka on October 29, 2014. Photo credit: Ishara S.KODIKARA/AFP/Getty Images.

One hundred feared dead after Sri Lanka monsoon rains trigger landslide
Torrential monsoon rains in Sri Lanka over the past two weeks triggered a deadly mudslide that hit the Meeriyabedda tea plantation near the town of Haldummulla, about 200 km (120 miles) east of the capital Colombo, in Sri Lanka Wednesday at 07:30 local time (02:30 GMT). According to Reuters, approximately 100 people are feared dead and 300 are missing, which would make the landslide one of the deadliest weather-related disasters of 2014. Some of the houses in the landslide were buried in 30 ft (9m) of mud.

Jeff Masters

Hurricane

A Rare Event: Heavy Rains in Northwest U.S. From an Ex-Hurricane

By: JeffMasters, 4:03 PM GMT on October 28, 2014

The heavy rains and strong gusty winds that began affecting the Northwest U.S. and Western Canadian coasts on Monday evening are due to a truly rare event: the remains of a Hawaiian hurricane getting slung into the coast as part of a large extratropical storm. The moisture is from Hurricane Ana, which, after making an extended tour just offshore of the Hawaiian islands last week, died on Sunday afternoon over the Pacific about 1,300 miles west of the California/Oregon border--unusually far to the northeast for a tropical cyclone to make it. In fact, there is only one other case since 1949 where the remnants of a hurricane that formed in the Eastern or Central Pacific has had a significant impact on the Pacific Northwest or Western Canada--an unnamed 1975 storm that maintained hurricane strength to 46.8°N (the latitude of the Oregon/Washington border.) That storm was the only hurricane on record to make it farther to the northeast of Hawaii than Ana, which maintained hurricane strength to a latitude of 36.3°N--approximately the latitude of Monterey, California. Even the notorious Hurricane Iniki, which hit Kauai as a Category 4 storm on September 11, 1992, only made it to 35°N latitude as a hurricane. Fortunately, ex-Ana's rains of 2 - 6" are not expected to cause serious flooding in the Pacific Northwest. The only Flood Watch for the storm is over Western Washington, where heavy rains in the Olympic Mountains may be enough to drive rivers close to flood stage.


Figure 1. MODIS satellite image of the extratropical storm containing the remains of Hurricane Ana impacting the Northwest U.S. and Western Canadian coasts on Monday afternoon, October 27, 2014. Image credit: NASA.


Figure 2. Tracks of all Central Pacific tropical depressions, tropical storms, and hurricanes to make it far to the north of the Hawaiian Islands (at least 34°N latitude.) Image credit: NOAA.


Figure 3. Departure of Sea Surface Temperature (SST) from average along the track of Hurricane Ana as of October 27, 2014. A large area of SSTs 2 - 3°F above average to the north of Hawaii allowed Ana to maintain hurricane strength much farther north than is usual in the Central Pacific. Warmer than normal ocean temperatures during the summer and fall of 2014 in the Central Pacific allowed a record three hurricanes--Iselle, Julio, and Ana--to come within 300 miles of the Hawaiian Islands. Image credit: Remote Sensing Systems.

Remnants of typhoons occasionally affect Pacific Northwest
There have been a number of Western Pacific typhoons that have died north of Hawaii and gone on to bring heavy rain to western Canada; this happens about twice per decade. According to wunderground's weather historian Christopher C. Burt, the most destructive storm in the history of the Pacific Northwest formed from the remnants of a Western Pacific typhoon. That storm was the notorious "Big Blow" or Columbus Day Storm of October 12, 1962 that killed 46 and caused $1.9 billion in damage (2014 dollars). The Western Pacific's Typhoon Freda, a Category 3 storm that formed near Wake Island west of the Date Line, became an extratropical storm with 45 mph winds shortly after crossing the Date Line, and went on to intensify into a 969 mb monster off the coast of Oregon that brought wind gusts as high as 145 mph to the coast that terrible October day in 1962.


Figure 3. The track of the Columbus Day storm from its inception as a typhoon on October 3 to the time it made landfall as a powerful extra-tropical storm on Vancouver Island, Canada on October 13th. The storm became extra-tropical in the West Pacific on October 9th. USWB chart reproduced in Weatherwise magazine’s December 1962 issue.


Figure 4. The Big Blow topples the Campbell Hall Tower on the campus of Western Oregon State College in Monmouth near Salem where 90 mph wind gusts were measured. Photo by Wes Luchau.

Remnants of Hanna bringing heavy rain to Central America
Tropical Storm Hanna dissipated on Monday evening over northern Nicaragua, just 14 hours after springing into life less than 50 miles off of the coast. Visible satellite images on Tuesday morning showed that the remnants of Hanna were over Northern Honduras and the Western Caribbean, and these heavy thunderstorms will move westwards over Belize, Northern Guatemala, and the Yucatan Peninsula Tuesday afternoon and into Wednesday, bringing areas of 3 - 5" of rain. The center of ex-Hanna was located just inland from the northern coast of Honduras on Tuesday morning, and was being tracked as Invest 96L by NHC.


Figure 5. Latest satellite image of 95L.

Invest 95L near the northern Lesser Antilles a possible threat to Bermuda
An area of disturbed weather (95L) associated with a tropical wave interacting with an upper level trough of low pressure is near the northern Lesser Antilles Islands, and is headed northwestward to west-northwestward at 10 to 15 mph. Satellite loops show that 95L has a modest amount of heavy thunderstorm activity that is poorly organized. Wind shear is high, 15 - 25 knots, and water vapor satellite images show that 95L has dry air to its north and west that is likely interfering with development. Sea Surface Temperatures (SSTs) are warm, about 29°C. The 8 am EDT Tuesday run of the SHIPS model predicted that wind shear would remain high for the next five days, limiting the prospects for development. None of our three reliable models for predicting tropical cyclone genesis predict development of 95L over the next five days. In their 8 am EDT Tuesday Tropical Weather Outlook, NHC gave the disturbance 2-day and 5-day development odds of 20% and 30%, respectively. The only land area at risk from 95L is Bermuda.


Figure 6. MODIS satellite image of Tropical Cyclone Nilofar in the Arabian Sea on Tuesday morning, October 28, 2014. At the time, Nilofar was an intensifying Category 4 storm with 130 mph winds. Image credit: NASA.

Tropical Cyclone Nilofar the 3rd strongest Arabian Sea storm on record
In the Arabian Sea between India and Africa, powerful Category 4 Cyclone Nilofar is putting on an impressive bout of rapid intensification as it heads northwards at 10 mph towards Pakistan. With wind shear a light 5 - 10 knots, excellent upper-level outflow, and very warm ocean temperatures about 1°C above average: 28 - 29°C (82 - 84°F), Nilofar may be able to continue intensifying until Wednesday morning, when very dry air from the deserts of the Middle East, combined with high wind shear, should be able to weaken the storm. Nilofar is expected to recurve to the northeast later this week, and the 00Z Tuesday runs of the UKMET and European models predicted the shear and dry air would be able to destroy Nilofar before it could make landfall. The GFS model keeps Nilofar as a weakening tropical storm at landfall near the Pakistan/India border around 00 UTC Saturday. Heavy rains are likely to be the most significant threat from the storm.

Intense hurricanes are rare in the Arabian Sea, due to the basin's small size, the interference of the summer monsoon, and the frequent presence of dry air and dust from the Arabian Peninsula. Nilofar's 130 mph sustained winds make it the third strongest tropical cyclone ever recorded in the Arabian Sea, behind the 165 mph winds of Category 5 Cyclone Gonu of 2007, which devastated Oman, and the 145 mph winds of Category 4 Cyclone Phet of 2010, which also did heavy damage in Oman. Fourth place is held jointly by the 2001 India Cyclone 01A and Very Severe Cyclonic Storm ARB 01 (02A) of 1999, which were Category 3 storms with 125 mph winds.

Eastern Pacific disturbance near tropical depression status
A well-organized area of disturbed weather in the Eastern Pacific a few hundred miles southwest of the Mexico/Guatemala border (Invest 93E) is close to tropical depression status. Our top three models for predicting tropical cyclone genesis all develop the system, and in their 8 am EDT Tuesday Tropical Weather Outlook, NHC gave the disturbance 2-day and 5-day odds of development near 100%. The storm's heaviest rains will remain well offshore from Mexico over the next five days.

Jeff Masters

Hurricane

Tropical Storm Hanna Forms Near Nicaragua

By: JeffMasters, 2:39 PM GMT on October 27, 2014

The 2014 Atlantic hurricane season kicked out another surprise, as Tropical Storm Hanna formed Monday morning off the coast of Nicaragua just six hours after NHC gave the system a 10% chance of development in their 2 am EDT Tropical Weather Outlook. Surface winds measured overnight by the ASCAT satellite showed sustained winds of 40 mph occurring off the northeast coast of Nicaragua, and visible satellite images just after sunrise on Monday morning confirmed the presence of a low-level surface circulation, prompting NHC to begin issuing tropical storm advisories. Hanna will be a short-lived storm. With a motion west-southwest at 7 mph, the center of Hanna will be over land on Monday afternoon, and passage over land should make the storm dissipate by Tuesday afternoon. The main threat of Hanna is heavy rains of 10 - 12" that will cause flash floods and mudslides over northeastern Honduras and Nicaragua. This portion of Nicaragua is still recovering from torrential rains last week that killed 24 people on October 20. As of 10 am EDT Monday, Puerto Lempira in northeast Honduras had received 0.71" of rain from Hanna.


Figure 1. MODIS satellite image of Tropical Storm Hanna making landfall in northeastern Nicaragua at approximately 11:30 am EDT October 27, 2014. Image credit: NASA.

Hanna's formation date of October 27 comes more than a month later than the typical September 24 formation date of the season's eighth named storm. Hanna gives the Atlantic 8 named storms, 6 hurricanes, and 2 major hurricanes so far in 2014. Between 1966 - 2009, the Atlantic averaged 11 named storms, 6 hurricanes, and 2 major hurricanes, so we are close to average in two of the three categories--hurricanes and major hurricanes. However, those hurricanes have not been as strong or long-lasting as usual, and the Accumulated Cyclone Energy (ACE) so far in 2014 is 65 units, which is well below the 110 units that occurs in a typical year.

Eastern Pacific disturbance may develop
An area of disturbed weather in the Eastern Pacific a few hundred miles southwest of the Mexico/Guatemala border is gradually becoming more organized, and has the potential to develop later this week. Our top three models for predicting tropical cyclone genesis all develop the system, and in their 8 am EDT Monday Tropical Weather Outlook, NHC gave the disturbance 2-day and 5-day odds of development of 40% and 80%, respectively. The storm's heaviest rains will remain well offshore from Mexico over the next five days.


Figure 2. MODIS satellite image of Tropical Cyclone Nilofar in the Arabian Sea on Monday morning, October 27, 2014. At the time, Nilofar was an intensifying Category 1 storm with 85 mph winds. Image credit: NASA.

Arabian Sea Cyclone Nilofar hits Category 1 strength
In the Arabian Sea between India and Africa, Category 1 Cyclone Nilofar has formed. With wind shear a light 5 - 10 knots, excellent upper-level outflow, and very warm ocean temperatures of 28 - 29°C (82 - 84°F), Nilofar appears likely to intensify into a Category 3 storm, despite the presence of very dry air from the deserts of the Middle East on the storm's west side. Nilofar is expected to recurve to the northeast later this week, and the 00Z Monday runs of the GFS and European models predicted a landfall near the Pakistan/India border between 18 UTC Friday and 03 UTC Saturday. Higher wind shear should induce significant weakening of Nilofar before it makes landfall.

Jeff Masters

Hurricane

Developing Cyclone Arabian Sea / INVEST 94L Caribbean / Warm Weather Ahead

By: JeffMasters, 6:09 PM GMT on October 25, 2014

(By Steve Gregory - Substituting for Dr. Masters who is taking the weekend off.)


UNUSUAL CYCLONE DEVELOPING IN ARABIAN SEA


A disturbance (INVEST IO90) in the Arabian Sea has been slowly developing into a Tropical Cyclone over the last few days, and appears very close to reaching Tropical Depression intensity. The developing storm is located about 600NM SE of the Oman coast, and remains quasi-stationary. Most models are showing intensification to a CAT 1 storm over the next 72 hours, and is forecast to move towards the OMAN coast by Tuesday. After which, the storm should turn northeast and accelerate away from the coast and weaken quickly to minimal tropical storm intensity (or depression) by next Thursday. It’s worth mentioning that latest imagery loops suggest very dry air is approaching from the Northwest – and this may prevent the storm from intensifying beyond Tropical Storm (gale) force – AND prevent the system from even approaching the Oman coast before it turns Northeast and weakens. Tropical Storms in this region of the world are unusual – but they are not rare ,

INVEST 94L UNLIKELY TO DEVELOP ANYTIME SOON

The remnants of TD #9 that moved into the western CARIB earlier this week, continues to drift E/SE as a frontal system from the Bahamas to the southern Yucatan with much drier air behind it keeps shunting this system further towards the SW CARIB Sea. With high wind shear near the frontal boundary and drier air still advancing into the NW CARIB – this system is unlikely to develop anytime soon. Should the system manage to survive beyond 5 days (doubtful!) conditions could become more favorable for development in the SW CARIB at the end of next week.


NATIONWIDE WARMTH BUT STORMY WEATHER NEXT WEEK

A nice warm-up is sweeping eastward from the central US towards the east as high pressure and dryer conditions develop over the eastern US during the next couple days. A strong upper level TROF moving across the northern Rockies will deepen and dig southeastward towards the Mid Atlantic states by late this week, with cooler air moving south into the Midwest and eventually the eastern US. The development of another coastal storm in the east is also possible along the frontal boundary late in the week as well. The overall hemispheric pattern continues to feature strong TROFS moving from the eastern Pacific across the nation every 5-7 days, with warm temps ahead of, and cooler conditions behind, each storm/frontal system. This highly progressive
Pattern is likely to keep average Temperatures on the warm side of normal through mid November.




Fig 1: This true color image of the Arabian Sea region from overnight (US time) shows a large – but slowly developing system about 600 NM off the Oman coast. This unusual (but not ‘rare’) development was ‘helped along’ by a strong MJO signal that persists over Africa and the Indian Ocean which tends to enhance convective based precipitation in the tropics..



Fig 2: The color enhanced IR image from this morning shows some heavier, but not intense, convection near the low-level circulation center (LLCC). The system does, however, exhibit significant rotation and banding features.




Fig 3: The surface analysis from 11:30Z using ship, land based and satellite derived winds (including data from the last 2 ASCAT passes) shows a large and slowly deepening area of Low pressure, with MAX winds in the 25Kt-30Kt range – right on the cusp of being designated as a Tropical Cyclone.




Fig 4: The High Level wind pattern shows a very large and well developed outflow pattern above the cyclone, with anti-cyclonic flow providing a venting mechanism for the developing surface cyclone. That said – there are no strong outflow channels – so development will continue to be slow.




Fig 5: The Intensity forecasts from the specialized cyclone models that are a ‘sub-set’ of the global models are in very good agreement that this system will reach hurricane intensity in a few days. But this is far from certain based on both Climatology and real-time imagery that shows drier air moving towards the system - but such good agreement amongst all the models does suggest intensification is likely.




Fig 6: The VIS image INVEST 94L in the western Caribbean. The system has been shifting towards the E/SE over the past day as cooler and drier air from the NW pushes into the NW CARIB.



Fig 7: The surface analysis from this morning shows a broad area of Low pressure (INVEST 94L) with a small, non-tropical Low pressure system over the Bahamas which brought very heavy rains to the Florida Keys and extreme SE Florida yesterday. Note the strong northerly flow over the Bay of Campeche that reaches into the eastern Pacific and could lead to the dissipation of INVEST 94L if this drier, more stable air continues advancing into the southwest CARIB.




Fig 8: The upper level wind analysis shows ‘one of the best’ anti-cyclonic circulation systems of the entire season over the western CARIB! If this was AUG – we almost certainly would be looking at a significant hurricane formation. But the reality of the season is evident just to the north - with a large TROF digging into the deep tropics with high wind shear (not shown) reaching into the NW Caribbean. IF the dry air/high wind shear intrusion ends soon enough, and the deep moisture field and vorticity associated with INVEST 94L survives, we might see some kind of development late next week in the SW CARIB – though the chances of that happening remain quite low.


CLICK IMAGE to open full size image in new window

Fig 9: The above set of 200 mb (~40,000’) charts highlighting the jet stream - shows the current pattern over North America (Left Panel) and the forecast wind pattern late TUE (center panel) and then next Friday (right panel). Note the VERY Strong wind Max over the northern Rockies (180mph speeds!). This is associated with a strong short wave TROF that will dig southeastward this week, leading to a deeper TROF over the eastern US at the end of next week. The warm weather that will prevail well into the middle of next week will ease back to near normal reading late next week as the TROF and a possible surface storm system impacts the eastern third of the nation. By that time – the next big TROF over the eastern Pacific will be approaching the west coast.



Fig 10: The Temperature forecasts based on the GFS MOS model data calls for well above normal readings across the nation during the next 7-Days – but is a bit misleading in that very warm anomalies early in the week will be offset by near or even slightly below normal Temps at the end of the 7-day period over the eastern half of the nation..




Fig 11: The Week 2 Temperature anomaly outlook continues to be on the warm side of normal for most of the nation – though Temps closer to or a bit below normal on average will prevail in the northeastern quarter of the nation.


✭ MY next Weather Update will be issued THURSDAY under my own BLOG unless conditions warrant an earlier update. ✭

Jeff will have a new post on Monday, unless 94L shows show unexpected development.

Steve

Hurricane Winter Weather arabian sea tropical cyclone

Invest 94L in Western Caribbean Little Threat to Develop

By: JeffMasters, 2:48 PM GMT on October 24, 2014

The remains of Tropical Depression Nine, which dissipated over Mexico's Yucatan Peninsula on Wednesday night, were moving offshore of Belize into the Western Caribbean on Friday morning. This disturbance is being labeled Invest 94L by NHC. Belize radar and satellite loops show that 94L has only a few poorly-organized clusters of heavy thunderstorms over the Yucatan Peninsula, Belize, Honduras, Guatemala, and the adjacent waters. None of our reliable models for predicting tropical cyclone genesis were predicting development of 94L in their Friday morning runs. A trough of low pressure connected to the large Nor'easter affecting the Northeast U.S. is bringing high wind shear of 15 - 25 knots to the Western Caribbean and is injecting dry air, which is discouraging development. The 8 am EDT Friday run of the SHIPS model indicates that these hostile conditions will persist into early next week. In their 8 am EDT Tropical Weather Outlook, NHC gave 94L 2-day and 5-day odds of development of 10%. If development does occur, Honduras, Belize, and Mexico's Yucatan Peninsula would be most at risk of receiving impacts from the storm.


Figure 1. Latest satellite image of Invest 94L in the Western Caribbean.

Eastern Pacific disturbance may develop
An area of disturbed weather in the Eastern Pacific a few hundred miles south of the Mexico/Guatemala border has changed little since Thursday, but has the potential to develop early next week. Our top three models for predicting tropical cyclone genesis all develop the system by early next week, and in their 8 am EDT Friday Tropical Weather Outlook, NHC gave the disturbance 2-day and 5-day odds of development of 0% and 50%, respectively. The storm's heaviest rains will likely remain offshore over the next five days.


Figure 2. VIIRS satellite image of Invest 90A in the Arabian Sea on Thursday, October 23, 2014. Image credit: NOAA Visualization Lab.

Arabian Sea disturbance may develop
In the Arabian Sea between India and Africa, an area of disturbed weather (Invest 90A) is growing more organized, and our top models for predicting tropical cyclone genesis, the GFS and European models, have been consistently predicting in recent runs that this disturbance will develop into a significant tropical cyclone by early next week. The Joint Typhoon Warning Center gives the disturbance a medium chance of developing by Saturday. Conditions are favorable for development, with moderate wind shear of 10 - 20 knots, excellent upper-level outflow, and very warm ocean temperatures of 28 - 29°C (82 - 84°F.) The storm will head slowly northwestwards, and the 00Z Friday runs of the GFS and European models predicted a landfall in Oman near 00 UTC Wednesday, October 29.


Video 1. New surveillance camera video released on October 23, 2014, of Hurricane Odile in Cabo San Lucas, Mexico, on September 14, 2014, as violent winds in the back eyewall destroyed the hotel lobby where the iCyclone chase team was sheltering.

Jeff Masters

Hurricane

Tropical Depression Nine Dissipates

By: JeffMasters, 1:45 PM GMT on October 23, 2014

Small and weak Tropical Depression Nine dissipated over Mexico's Yucatan Peninsula Wednesday night, shortly after making landfall near 8 pm EDT Wednesday October 22, 2014 on the western shore of the peninsula. Mexican radar out of Sabancuy and satellite loops show that ex-TD 9 is bringing some heavy rains to the Yucatan Peninsula, Belize, Guatemala, and the adjacent waters, and this activity will continue into the weekend. By Saturday, some of the spin associated with TD 9 may emerge over the Western Caribbean, and we should carefully watch this area on Sunday and Monday for tropical cyclone development--though none of our reliable models were predicting development in their Thursday morning runs. A trough of low pressure connected to the large Nor'easter affecting the Northeast U.S. will inject a large amount of dry air into the Western Caribbean this weekend, discouraging development, and wind shear is expected to be a rather high 15 - 25 knots, which should keep any development slow. If development does occur, Honduras, Belize, and Mexico's Yucatan Peninsula would be most at risk of receiving impacts from the storm.


Figure 1. MODIS satellite image of TD 9 in the Gulf of Mexico on Wednesday afternoon, October 22, 2014. Image credit: NASA.

Eastern Pacific disturbance may develop
An area of disturbed weather in the Eastern Pacific a few hundred miles south of the Mexico/Guatemala border may end up impacting whether or not a tropical depression can form in the Western Caribbean from ex-TD 9. The Eastern Pacific disturbance is close enough to the Western Caribbean to compete for energy and moisture, and upper-level outflow from the Eastern Pacific storm could bring high wind shear over the Western Caribbean. Our top three models for predicting tropical cyclone genesis all develop the Eastern Pacific disturbance by early next week, and in their 8 am EDT Thursday Tropical Weather Outlook, NHC gave the disturbance 2-day and 5-day odds of development of 0% and 50%, respectively. The storm will move slowly northwards, and will likely bring heavy rains to the coast of Mexico and Guatemala this weekend.

Arabian Sea disturbance may develop
In the Arabian Sea between India and Africa, an area of disturbed weather (Invest 90A) has formed, and our top models for predicting tropical cyclone genesis, the GFS and European models, have been consistently predicting in recent runs that this disturbance will develop into a significant tropical cyclone by early next week. The Joint Typhoon Warning Center gives the disturbance a low chance of developing by Friday, but notes conditions are favorable for development, with moderate wind shear of 10 - 20 knots, excellent upper-level outflow, and very warm ocean temperatures of 28 - 29°C (82 - 84°F.) The storm will head slowly northwards over the next week, and is not a threat to make landfall for at least five days.


Figure 2. MODIS satellite image of Invest 90A in the Arabian Sea on Thursday morning, October 23, 2014. Image credit: NASA.

Jeff Masters

Hurricane

Tropical Depression Nine Forms in Gulf of Mexico

By: JeffMasters, 1:56 PM GMT on October 22, 2014

Tropical Depression Nine has formed in the Gulf of Mexico's Bay of Campeche, and will bring dangerous heavy rains of 5 - 10 inches to Mexico's Yucatan Peninsula the next two days. Satellite loops show that TD 9 has only a small amount of heavy thunderstorms near its center, and these thunderstorms are poorly organized, due to high wind shear of 20 - 30 knots. Mexican radar out of Sabancuy showed only one spiral band associated with the storm. Dry air from Mexico flowing eastwards over the western Gulf of Mexico is slowing development, but the topography of the mountains along the southern coast of the Bay of Campeche is helping to create counter-clockwise spin for TD 9, and likely aided in its formation despite the high wind shear. Sea Surface Temperatures (SSTs) are very warm, about 29.5°C. An Air Force hurricane hunter aircraft was investigating TD 9 on Wednesday morning, and found a well-defined surface circulation, top surface winds near 35 mph, and a central pressure of 1003 mb at 8:25 am EDT.


Figure 1. MODIS satellite image of TD 9 in the Gulf of Mexico on Wednesday afternoon, October 22, 2014.


Figure 2. Mexican radar out of Sabancuy showing one spiral band associated with TD 9 at 8:30 am EDT Wednesday October 22, 2014.

Forecast for TD 9
TD 9 is expected to move eastwards into Mexico's Yucatan Peninsula on Wednesday night, and likely has time to intensify into a 45 mph tropical storm, at the strongest, before making landfall. (The next name on the tropical storm list is Hanna.) The storm will spend most of Thursday with its center over land, and is small enough that passage over land may cause it to dissipate. Once TD 9 or its remnants are over the Western Caribbean on Friday and Saturday, it will interact with a trough of low pressure connected to the large Nor'easter affecting the Northeast U.S. The 8 am EDT Wednesday run of the SHIPS model predicts that while wind shear will fall to the moderate range, 10 - 20 knots, Thursday - Saturday, the trough will inject a large amount of dry air, discouraging development. The trough of low pressure will pull out of the Western Caribbean on Saturday, and may leave behind an area of spin in the Western Caribbean that would potentially have the capability to develop into a strong tropical storm or hurricane, as predicted by many of the ensemble members of the 00Z Wednesday morning run of the GFS model. The European and UKMET models are not showing this solution, but I think we have to be concerned about the possibility of a potentially dangerous tropical cyclone in the Western Caribbean early next week. It's a complicated meteorological situation, and the long-term forecast is murky.

Jeff Masters

Hurricane

Gulf of Mexico's 93L a Heavy Rain Threat; Ana Leaves Hawaii Alone

By: JeffMasters, 3:25 PM GMT on October 21, 2014

An area of low pressure over the Gulf of Mexico's Bay of Campeche (93L) contains moisture and spin from the Eastern Pacific's Tropical Storm Trudy, which made landfall near Acapulco last weekend. 93L will bring heavy rains to Mexico's Yucatan Peninsula, Western Cuba, and South Florida Wednesday through Friday. Satellite loops show the low has a moderate degree of spin and plenty of heavy thunderstorm activity, but these thunderstorms are poorly organized, due to high wind shear of 30 knots. Mexican radar out of Altamira does show at least one spiral band had formed near the coast Tuesday morning, though. Water vapor satellite images show there is dry air from Mexico flowing eastwards over the western Gulf of Mexico, which is likely slowing development. Sea Surface Temperatures (SSTs) are very warm, about 29.5°C. The 8 am EDT Tuesday run of the SHIPS model predicted that wind shear would fall to the moderate range, 10 - 20 knots, Wednesday - Friday, giving 93L a better chance to develop then. The Tuesday morning runs of our three reliable models for predicting tropical cyclone genesis, the European, GFS and UKMET models, all showed support for some slow development of 93L this week. The storm is likely to move slowly eastwards across the Bay of Campeche on Tuesday and Wednesday, cross over the Yucatan Peninsula on Thursday, move through the Florida Straits between Cuba and South Florida on Friday, then into the Bahamas on Saturday. Along its path, 3 - 6" of rain are are likely--with higher rainfall amounts to be expected if 93L ends up developing into a tropical depression. In their 8 am EDT Tuesday Tropical Weather Outlook, NHC gave 93L 2-day and 5-day development odds of 40% and 50%, respectively. A hurricane hunter mission is scheduled to investigate 93L Tuesday afternoon, but may be cancelled.

The prospects of 93L developing into a damaging hurricane are very low, and this storm is primarily a heavy rain threat. However, both the GFS and European models show the possibility that the trough of low pressure expected to pick up 93L and pull it northeastwards out to sea this weekend may leave behind an area of spin in the Western Caribbean early next week that would potentially have the capability to develop into a more dangerous tropical cyclone than 93L. It's too early to be sold on this model solution yet, but we should pay attention to the evolution of this storm system over the coming week.


Figure 1. Latest satellite image of Invest 93L in the Gulf of Mexico.


Figure 2. Predicted precipitation for the 5-day period ending Sunday, October 26, 2014. 93L is predicted to bring rainfall amounts of up to five inches to South Florida. Image credit: National Weather Service.

Eastern Atlantic disturbance 92L little threat
A large non-tropical low pressure system spinning in the Eastern Atlantic a few hundred miles south-southeast of the Azores Islands (92L) brought heavy rains and flash flooding that killed five people in the Canary Islands on Sunday. This low is headed slowly westwards into a region with higher wind shear, and should not affect any more land areas. In their 8 am EDT Tuesday Tropical Weather Outlook, NHC gave 2-day and 5-day development odds of 10%.


Figure 3. MODIS satellite image of Tropical Storm Ana brushing the Hawaiian Islands at 7:55 pm EDT on Monday October 20, 2014. At the time, Ana had top winds of 65 mph, and high wind shear had allowed the surface circulation to be exposed to view. Image credit: NASA.


Figure 4. Radar-estimated rainfall from the Molokai radar for Hurricane Ana shows that extreme rains of 15+" fell just 20 miles off the coast from Honolulu.

Tropical Storm Ana headed away from Hawaii
Tropical Storm Ana is headed northwestwards away from the Hawaiian Islands; all watches and warnings have been dropped for the main Hawaiian Islands. Heavy rains of 4.72" fell in Honolulu from Ana, and widespread rain amounts of 4 - 7" were reported on Oahu. The island was very fortunate, though, since a large area of 15+" of rain fell just 20 miles offshore, according to radar estimates. Satellite loops on Tuesday morning showed that Ana was having trouble with high wind shear, with the surface circulation partially exposed to view. Ana will turn north and then northeast over the next few days and gradually weaken over cooler waters, without affecting any other land areas.

Jeff Masters

Hurricane

Earth Headed For its Hottest Year on Record After a Record-Warm September

By: JeffMasters, 5:38 PM GMT on October 20, 2014

September 2014 was Earth's warmest September on record, the period January - September was tied with 1998 and 2010 as the warmest first three-quarters of any year on record, and the past 12 months--October 2013 through September 2014--was the warmest consecutive 12-month period among all months since records began in 1880, said NOAA's National Climatic Data Center (NCDC) today. NASA also rated September 2014 as the warmest September on record. If 2014 maintains the same temperature departure from average for the remainder of the year as was observed during January - September, it will be the warmest calendar year on record. September is the fourth time NOAA has ranked a 2014 month as the warmest on record; May, June, and August 2014 were also the warmest such months on record. (April 2014 was originally ranked as tied for warmest April on record, but has since been revised downwards to the second warmest April on record.) Global ocean temperatures during September 2014 were the warmest on record, and the 0.66°C (1.19°F) ocean temperature anomaly was the highest ever measured, beating the record set just the month previously in August 2014. Global land temperatures in September 2014 were the 6th warmest on record. Global satellite-measured temperatures in September 2014 for the lowest 8 km of the atmosphere were the 14th or 7th warmest in the 36-year record, according to Remote Sensing Systems and the University of Alabama Huntsville (UAH), respectively. Wunderground's weather historian, Christopher C. Burt, has a summary of September 2014's extreme weather.


Figure 1. Departure of temperature from average for September 2014, the warmest September for the globe since record keeping began in 1880. Record warmth was notable in much of northwestern Africa, coastal regions of southeastern South America, southwestern Australia, parts of the Middle East, and regions of southeastern Asia. In total, 31 countries and territories from all seven continents around the world had at least one station that reported record warmth. Cooler than average temperatures were uncommon world-wide. Image credit: National Climatic Data Center (NCDC) .



Four billion-dollar weather disasters in September 2014
Four billion-dollar weather-related disasters hit the Earth during September 2014, according to the September 2014 Catastrophe Report from insurance broker Aon Benfield. This brings the global number of billion-dollar weather disasters for the first eight months of 2014 to 21. This is well behind the record-setting pace of 2013, which had 33 billion-dollar weather disasters by the end of September, and ended up with a record 41 by the end of the year. Here are September 2014's billion-dollar weather disasters:


Disaster 1. Torrential monsoon rains of over 12" (305 mm) lashed the India-Pakistan border region of Kashmir and Jammu Provinces on September 3 - 7, triggering devastating floods that swept through the mountainous region, killing at least 648 people and doing $18+ billion in damage. Hardest-hit were India's Jammu and Kashmir region, where damages were estimated at $16+ billion. According to EM-DAT, the International Disaster Database, this is the most expensive natural disaster in India's history, surpassing the $11.6 billion price tag (2014 dollars) of the July 1993 monsoon floods. In Pakistan, at least 207 people died and damage was estimated at $2 billion. Crippling and catastrophic floods have become the new normal in Pakistan, where the six most expensive floods in their history have come in the past eight years--2010, 2011, 2012, 2014, 2007, and 2013. In this image, we see Kashmiri residents struggling to withstand sudden and strong water currents while wading through floodwaters in their efforts to move to safer places in Srinagar, India, Thursday, Sept. 4, 2014. (AP Photo/Dar Yasin)


Disaster 2. Typhoon Kalmaegi hit the Philippines, China, and Vietnam between September 10 - 16, killing at least 31 and doing $3 billion in damage. The typhoon's first landfall, as a Category 1 storm, came in the Philippines’ Luzon Island, where 12 people were killed and at least 1,500 homes damaged, with damages estimated at $14 million. Kalmaegi killed nine people in China and did $2.9 billion in damage. In Vietnam, ten people were killed across northern sections of the country, and damages were estimated at $4.5 million. In this image, we see Kalmaegi as it swirled to the south of the island of Taiwan at night, as seen from the International Space Station by astronaut Reid Wiseman ‏(@astro_reid) at 3 pm EDT September 14, 2014. At the time, Kalmaegi had just crossed the Philippines' Luzon Island as a Category 1 typhoon, and had weakened to a tropical storm with 70 mph winds. Hong Kong is the other bright patch of lights. Image credit: Reid Wiswman.


Disaster 3. Hurricane Odile made landfall near Cabo San Lucas, Mexico on September 15, 2014, as a Category 3 storm with 125 mph winds. Odile was the strongest storm on record to hit Mexico’s Baja California Peninsula, and killed five people and injured 135. Tens of thousands of homes, structures and vehicles were damaged or destroyed by Odile’s high winds and flooding rains, and total damage was estimated at $2 - $4 billion. This is a MODIS satellite image of Hurricane Odile off the coast of Mexico's Baja Peninsula, taken at approximately 2 pm EDT Sunday September 14, 2014. At the time, Odile was a Category 3 storm with 125 mph winds. Image credit: NASA.


Disaster 4. Torrential rains in southwestern China on September 10 - 17 killed 50 and did $1.4 billion in damage. In this VIIRS satellite image from September 16, 2014, we see Typhoon Kalmaegi hitting southeast China at the same time as torrential rains from unrelated thunderstorms are affecting southwest China. Image credit: NOAA Visualization Lab.

An El Niño Watch continues
September 2014 featured neutral El Niño conditions in the equatorial Eastern Pacific, and sea surface temperatures were about 0.3°C above average in September in the so-called Niño 3.4 region (5°S - 5°N, 120°W - 170°W), where SSTs must be at least 0.5°C above average for five consecutive months for an El Niño event to be declared. NOAA is continuing its El Niño Watch, and is giving a 2-in-3 chance of an El Niño developing this winter.

Arctic sea ice falls to 6th lowest September extent on record
Arctic sea ice extent during September 2014 was the 6th lowest in the 36-year satellite record and was similar to September 2013 levels, according to the National Snow and Ice Data Center (NSIDC). On September 17th, the Artic sea ice extent reached its annual minimum, two days later than average. The Northern Sea Route (also known as the Northeast Passage)--the shipping lane along the north coast of Russia in Arctic waters--was open for over a month in 2014, according to ice edge analyses by the National Snow and Ice Data Center and the University of Illinois Cryosphere Today. The Northwest Passage through the Arctic waters of Canada did not open in 2014. Mariners have been attempting to sail these passages since 1497. The Northeast Passage opened to ice-free navigation for the first time in recorded history in 2005, with the Northwest Passage following suit during the summer of 2007. Both passages have been open multiple summers since then, as long-term melting of the ice has continued. However, this summer's weather in the Arctic featured winds favorable for not letting sea ice drift out through Fram Strait, and we have seen the total volume of sea sea as estimated by the University of Washington PIOMAS model pull back from the record low set in 2012. Some of the 2nd-year ice that survived the summer of 2013 has also survived the summer of 2014, so the ice pack is armoring itself a bit going into 2015 with a modest amount of multi-year ice compared to what we went into 2012 with (2012 set the record for lowest Arctic sea ice extent.)

Most spectacular weather videos of September

Video 1. Torrential rains in Serbia caused flash floods that killed one person and swept way cars, as seen in this video.


Video 2. A remarkable storm surge with high waves sweeps vehicles away along the northeastern coast of Turkey on the Black Sea on September 24, 2014. The surge was caused by a large 990 mb low; underground member barbamz saved a satellite image of the storm here.


Video 3. Spectacular sunset, aurora, and sunrise from the top of Mt. Washington, New Hampshire on September 12 - 13, 2014.

Mike Olbinsky's 7-minute video, Monsoon, taken during the June 15 - September 15 2014 Arizona monsoon season, has some amazing time-lapse video. I particularly like the sunset and rainbow at 2:15, the thunderstorm at 5:42, the "haboob" dust storm at 6:13.

Commentary
Earth's temperature so far in 2014 has been the warmest ever recorded without an El Niño event present, and could well be Earth's hottest year on record if current trends continue. If NOAA's predicted 2-in-3 chance of an El Niño event this winter verifies, and the exceptional warmth of 2014 carries over into 2015, next year could well be Earth's second consecutive hottest year on record, and be accompanied by unprecedented regional heat waves and droughts.

Jeff Masters

Climate Summaries

Gulf of Mexico's 93L a Heavy Rain Threat; 92L Kills 5 in Canary Islands

By: JeffMasters, 3:29 PM GMT on October 20, 2014

Moisture from Tropical Storm Trudy, which made landfall on the Pacific coast of Mexico about 75 miles east-southeast of Acapulco on Saturday morning, has moved northwards across Mexico into the southern Gulf of Mexico's Bay of Campeche. A large area of low pressure (93L) is forming there, and will bring heavy rains to Mexico's Yucatan Peninsula, Western Cuba, and South Florida on Wednesday through Friday. Satellite loops show the low has plenty of heavy thunderstorm activity, but these thunderstorms are poorly organized, due to high wind shear of 30 knots. Water vapor satellite images show there is dry air from Mexico flowing eastwards over the central Gulf of Mexico, which may slow development. Sea Surface Temperatures (SSTs) are very warm, about 29.5°C. The 8 am EDT Monday run of the SHIPS model predicted that wind shear would fall to the moderate range, 10 - 20 knots, Wednesday - Friday, giving 93L a better chance to develop in the later part of the week. The Monday morning runs of our three reliable models for predicting tropical cyclone genesis, the European, GFS and UKMET models, all showed support for some slow development of 93L this week. In their 8 am EDT Monday Tropical Weather Outlook, NHC gave 93L 2-day and 5-day development odds of 30% and 40%, respectively. The low should move generally eastward or east-northeastward during the week, spreading heavy rains, with rainfall amounts of 4 - 8" likely over Mexico's Yucatan Peninsula, Western Cuba, and South Florida.


Figure 1. Latest satellite image of Invest 93L in the Gulf of Mexico.


Figure 2. Predicted precipitation for the 7-day period ending Monday, October 27, 2014. 93L is predicted to bring rainfall amounts of 4 -8 inches to South Florida. Image credit: National Weather Service.

Flooding from 92L kills five in the Canary Islands
A large non-tropical low pressure system spinning in the Eastern Atlantic between the Canary Islands and Azores Islands (92L) brought heavy rains and flash flooding that killed five people in the Canary Islands on Sunday. At Santa Cruz in the islands, 5.35" (136 mm) of rain fell in just six hours. This low is headed slowly westwards, and should not affect any more land areas. The 8 am EDT Monday run of the SHIPS model predicted that wind shear would be moderate this week over 92L, 15 - 20 knots, but ocean temperatures would be quite cool, around 23°C (73°F.) These conditions are marginally favorable for formation of a subtropical storm, and in their 8 am EDT Tropical Weather Outlook, NHC gave 2-day and 5-day development odds of 10% and 30%, respectively.


Video 1. Torrential rains in the Canary Islands caused flash flooding that killed five people on Sunday, October 19, 2014.

Ex-Gonzalo to bring high winds to the U.K. on Tuesday
Hurricane Gonzalo transitioned to a powerful extratropical storm with hurricane-force winds on Sunday afternoon after speeding by southeast Newfoundland, Canada on Sunday morning as a Category 1 hurricane with 85 mph winds. Cape Race, Newfoundland measured sustained winds of 41 mph, gusting to 55 mph at 8:30 am local time as Gonzalo moved past. Gonzalo hit Bermuda near 8:30 pm EDT Friday night as a strong Category 2 storm with sustained 110 mph winds, causing moderate damage but no loss of life. On Tuesday, the powerful extratropical storm that was Gonzalo will hit the U.K., bringing wind gusts of 50 - 80 mph. The UK Met Office has posted a "Yellow warning of wind" for the islands for Tuesday, with the highest wind gusts of 80 mph expected around coasts in northern Scotland.


Figure 3. MODIS satellite image of Hurricane Ana brushing the Hawaiian Islands on Sunday morning October 19, 2014. At the time, Ana had top winds of 80 mph. Image credit: NASA.

Tropical Storm Ana bringing heavy rains to Hawaii
Tropical Storm Ana continues to trek westwards away from the Hawaiian Islands, but its outer bands are still bringing heavy rains to Oahu and Kauai, where Flash Flood Watches are in effect. Rainfall amounts of 3 - 6" with locally higher amounts are expected before Ana finally chugs out to sea. Ana dumped 3.4" of rain on Honolulu on Sunday, a record for the date. Satellite loops on Monday morning showed that Ana was holding its own against high wind shear, and the storm is likely to re-intensify into a hurricane by Tuesday when the shear relaxes.

Jeff Masters

Hurricane

Gonzalo Brushes Newfoundland; Ana Drenching Hawaii

By: JeffMasters, 4:54 PM GMT on October 19, 2014

Hurricane Gonzalo sped by Southeast Newfoundland, Canada on Sunday morning as a Category 1 storm with 85 mph winds. Cape Race, Newfoundland measured sustained winds of 41 mph, gusting to 55 mph at 8:30 am local time; Cape Pine measured a gust of 66 mph. Despite traversing waters colder than 10°C (50°F), Gonzalo was still maintaining its tropical characteristics on Sunday morning, and had a respectable amount of heavy thunderstorms near its center. The hurricane can't maintain its tropical nature for much longer, and will become an extratropical storm by Sunday night. On Tuesday, the powerful extratropical storm that was Gonzalo will hit the U.K., bringing wind gusts of 50 - 70 mph. The UK Met Office has posted a "Yellow warning of wind" for the islands for Tuesday.

Gonzalo hit Bermuda near 8:30 pm EDT Friday night as a strong Category 2 storm with sustained 110 mph winds. Sustained winds at the Bermuda Airport peaked at 76 mph, with a gust to 96 mph, as the northern eyewall passed overhead between 8 - 9 pm AST. After a calm lasting about an hour, when the pressure sank to 953 mb, the southern eyewall hit, with stronger winds than the northern eyewall--93 mph, gusting to 113 mph, at 11:55 pm AST. No one was killed on the island, and damage was moderate. The airport is scheduled to re-open on Sunday afternoon.


Figure 1. Workers use a chainsaw to remove an uprooted tree from a street in downtown after hurricane Gonzalo hit the island in Hamilton, Bermuda, Saturday Oct. 18, 2014. (AP Photo/David Skinner) BERMUDA OUT

Hurricane Ana bringing heavy rains to Hawaii
Hurricane Ana continues to trek just over 100 miles south of the Hawaiian Island chain as a Category 1 hurricane with 80 mph winds. Satellite loops on Sunday morning showed that Ana was holding its own against high wind shear, and the hurricane was bringing heavy rains to Oahu and Kauai, where Flash Flood Watches are in effect. Rainfall amounts of 3 - 6" with locally higher amounts are expected before Ana finally chugs out to sea. Ana dumped 4.55" or rain on Hilo on the Big Island on Saturday, a record for the date.


Figure 2. MODIS satellite image of Hurricane Ana brushing the Hawaiian Islands on October 18, 2014. At the time, Ana had top winds of 80 mph. Image credit: NASA.


Figure 3. Radar image of Ana at 12:22 pm EDT October 19, 2014, from the South Kauai radar.


Figure 4. Radar-estimated total rainfall from Ana from the Molokai Radar.

Tropical Storm Trudy dissipates after hitting Mexico
In the Eastern Pacific, Tropical Storm Trudy formed Friday night and made landfall on the Pacific coast of Mexico about 75 miles east-southeast of Acapulco on Saturday morning with sustained winds of 60 mph. Acapulco radar and satellite images show that very heavy rains from Trudy continue to affect the coast of Mexico, and Trudy's remnants have the potential to dump rains totaling 6 - 12 inches through Wednesday in the states of Guerrero and Oaxaca in southern Mexico. Trudy's formation gives the 2014 Eastern Pacific (east of 140°W) 19 named storms, 13 hurricanes, and 8 intense hurricanes in 2014. An average Eastern Pacific hurricane season sees just 15 named storms, 8 hurricanes, and 3 intense hurricanes during the entire year, with only one more named storm occurring after October 18.

Two areas to watch in the Atlantic
Moisture from Trudy will move northwards across Mexico into the southern Gulf of Mexico's Bay of Campeche by Wednesday, contributing to the formation of a large area of low pressure that will bring heavy rains to Mexico's Gulf Coast, Western Cuba, and South Florida on Wednesday through Friday. In their 8 am EDT Sunday Tropical Weather Outlook, NHC gave this low 2-day and 5-day odds of development into a tropical or subtropical cyclone of 0% and 30%, respectively. The low should move generally eastward or east-northeastward during the week.

NHC is also watching a non-tropical low pressure system in the Eastern Atlantic between the Canary Islands and Azores Islands. This system was designated 92L on Sunday, and was given 5-day development odds of 20%.

Hurricane expert Steve Gregory has his take on the tropics in a Sunday afternoon post.

Jeff Masters

Hurricane

Category 2 Gonzalo Hits Bemuda; Hurricane Ana Brushing Hawaii; Trudy Drenching Mexico

By: JeffMasters, 2:46 PM GMT on October 18, 2014

Hurricane Gonzalo made a direct hit on the island of Bermuda near 8:30 pm EDT Friday night rated by NHC as a strong Category 2 storm with sustained 110 mph winds. Sustained winds at the Bermuda Airport peaked at 76 mph, with a gust to 96 mph, as the northern eyewall passed overhead between 8 - 9 pm ADT. After a calm lasting about an hour, when the pressure sank to 953 mb, the southern eyewall hit, with stronger winds than the northern eyewall--93 mph, gusting to 113 mph, at 11:55 pm ADT. An unofficial gust of 144 mph was recorded at Commissioners Point at an elevation of 262', a site notorious for recording strong winds due to local terrain effects. In addition, a sustained wind of 89 mph gusting to 144 mph was reported at an elevation of 159' at St. Davids near the airport (thanks to wunderground member BDAwx for this stat.)


Figure 1. MODIS satellite image of Hurricane Gonzalo taken at approximately 11:00 am EDT October 17, 2014. At the time, Gonzalo had top winds of 125 mph, and was embedded in a cold front whose clouds extended northwards past Cape Cod, Massachusetts and into Nova Scotia, Canada. Image credit: NASA.


Figure 2. Gonzalo as seen by the Bermuda radar at 9:43 pm ADT October 17, 2014, when the eye was over the island. Image credit: Bermuda Weather Service.

Gonzalo's damage not as heavy as Fabian's of 2003
Thankfully, no one was killed on Bermuda from Gonzalo. Damage on the island was considerable, though appears to be much lower than that wrought by Category 3 Hurricane Fabian of 2003, the only hurricane to get its name retired exclusively because of its impact on the island of Bermuda. Fabian did $300 million in damage, making it the most expensive hurricane ever to hit the island. Fabian's storm surge destroyed the causeway connecting the airport to the rest of the island, and this causeway withstood Gonzalo's impact--though divers are scheduled to inspect its footings Saturday afternoon before reopening will occur. Damage at the airport was mostly minor (roof damage and minor flooding), and all the navigational infrastructure seems intact. The storm surge damaged the airport's weather sensors, though, according to the Bermuda Weather Service. According to the island's utility provider, BELCO, about 35,700 of the island's 36,000 metered homes were without power at the height of Gonzalo. Virtually all of the island's major roads were blocked by downed trees and power lines.


Video 1. This time-lapse animation shows the evolution of Gonzalo (viewed in infrared, but overlaid on the Blue Marble) from midday on October 13 to midday on October 17, 2014. Images were acquired by the GOES-East geosynchronous weather satellite, which was built by NASA and is operated by the National Oceanic and Atmospheric Administration.


Video 2. Powerful winds sweep across Bermuda on the evening of October 17, 2014, as Hurricane Gonzalo makes landfall. Video by Nicholas Ferrando.


Figure 3. Bermuda Weather Service Meteorological Technician Wayne Little waiting for the lull to release the 00Z (8 pm EDT) weather balloon/sonde into the eye of Hurricane Gonzalo on October 17, 2014. The balloon was successfully launched, and returned a sounding showing a very moist and warm atmosphere inside the eye--no surprise, since hurricanes are warm-cored low pressure systems. Image credit: Bermuda Weather Service

Gonzalo headed towards Canada
Gonzalo is steadily weakening as it speeds north-northeastwards towards Canada. Infrared and visible satellite loops on Saturday morning showed that Gonzalo had lost its well-defined eye, and the storm had been stretched into an elliptical shape by high wind shear. Gonzalo is still expected to have Category 1 strength winds when it makes its closest pass by Southeast Newfoundland, predicted to occur between 4 am - 6 am EDT Sunday by the 00Z Saturday runs of the GFS and European models. In their 5 am EDT Saturday Wind Probability Forecast, NHC gave Cape Race, Newfoundland a 57% chance of experiencing tropical storm-force winds, and a 1% chance of hurricane-force winds. Heavy rains from ex-Gonzalo are likely to be the main threat to Newfoundland.


Figure 4. MODIS satellite image of Hurricane Ana near the Big Island of Hawaii taken on October 17, 2014. At the time, Ana had top winds of 75 mph. Image credit: NASA.


Figure 5. Radar image of Ana at 10:20 am EDT OCtober 18, 2014, from the Kona radar.

Hurricane Ana bringing heavy rains to Hawaii
Hurricane Ana took advantage of light wind shear and warm Sea Surface Temperatures (SSTs) warm of 27.4°C (81°F) to intensify into a Category 1 hurricane with 85 mph winds as of 5 am EDT on Saturday, but is not a threat to make a direct hit on any of the Hawaiian Islands. Satellite loops on Saturday morning showed that Ana had its most impressive appearance yet, with a large area of heavy thunderstorms, plenty of low level spiral bands, and solid upper-level outflow to the north and east. Heavy rains causing flash floods and mudslides are a major concern. Rainfall amounts of 6 - 8 inches are possible on the Big Island, where a Flash Flood Watch is in effect. Portions of the island had received 2 - 3" of rain as of Saturday morning, according to radar estimates.

Related posts
Climate Change May Increase the Number of Hawaiian Hurricanes, my August 6, 2014 post
Climatic Atlas of Tropical Cyclone Tracks over the Central North Pacific (2008)

Tropical Storm Trudy hits Mexico
In the Eastern Pacific, Tropical Storm Trudy formed Friday night and was making landfall on the Pacific coast of Mexico about 75 miles east-southeast of Acapulco on Saturday morning with sustained winds of 60 mph. Acapulco radar is showing very heavy rains affecting the coast, and Trudy has the potential to dump rains of 6 - 12 inches during the next few days in the states of Guerrero and Oaxaca in southern Mexico. Moisture from Trudy will move northwards across Mexico into the southern Gulf of Mexico's Bay of Campeche by early next week, contributing to the formation of a large area of low pressure that will bring heavy rains to Mexico's Gulf Coast, Western Cuba, and South Florida on Wednesday through Friday.

Jeff Masters

Hurricane

Category 3 Gonzalo Pounding Bermuda; Ana a Heavy Rainfall Threat for Hawaii

By: JeffMasters, 3:10 PM GMT on October 17, 2014

The winds are rising and huge waves are pounding Bermuda as powerful Category 3 Hurricane Gonzalo closes in with sustained 125 mph winds. Gonzalo is gradually weakening, thanks to wind shear that has risen to a moderate 15 knots and Sea Surface Temperatures (SSTs) that have cooled to 28°C (82°F). However, Gonzalo is not weakening fast enough to spare Bermuda from a devastating strike by a major hurricane. Infrared and visible satellite loops on Friday morning showed that Gonzalo remained an impressive hurricane with a large area of intense heavy thunderstorms, good spiral banding, and solid upper-level outflow to the north. The appearance of the storm was somewhat ragged, with the storm stretched into an elliptical shape and the eye filled with clouds. But Friday morning data from the Hurricane Hunters during their 9 am EDT eye pass showed that Gonzalo remained a dangerous Category 3 hurricane with a central pressure of 947 mb and surface winds of 125 mph. With an eye 35 miles in diameter, Gonzalo's strongest eyewall winds were spread out over an area about 45 miles across.


Figure 1. Hurricane Gonzalo as seen from the International Space Station on October 16, 2014. Image credit: Alexander Gerst.


Figure 2. Gonzalo as seen by the Bermuda radar at 11:53 am EDT October 17, 2014. The eye was visible at the bottom of the image. Image credit: Bermuda Weather Service.

Forecast for Gonzalo
The 8 am Friday run of the SHIPS model predicts that wind shear will stay a moderate 10 - 20 knots through Friday night as Gonzalo approaches Bermuda, and SSTs will cool to 27°C (81°F.) These conditions should drive some modest weakening, but it is likely that Gonazalo will be a dangerous Category 2 or 3 storm with 100 - 115 mph winds at the time of its closest approach to Bermuda on Friday evening. The latest suite of model runs has the hurricane passing over or less than 30 miles to the west of the island, which would put Bermuda in the strong right-front quadrant of the storm, potentially bringing them the strongest winds of Gonzalo's eastern eyewall. However, late morning radar and visible satellite images show Gonzalo taking a course more directly at the island or slightly to the east, which means that the island would be more likely to get the weaker west side of the eyewall. Hurricane-force winds extend outwards about 60 miles from the center, so Bermuda is almost certain to see hurricane-force winds, though. In their 11 am EDT Friday Wind Probability Forecast, NHC gave Bermuda a 96% chance of sustained hurricane-force winds of 74+ mph. In their 12:30 pm AST advisory, the Bermuda Weather Service called for elevated locations on the island to see sustained winds of 105 - 125 mph (90 - 110 knots) gusting to 160 mph Friday evening. Seas were forecast to be 30 - 40 outside the reef, and 4 - 7 feet inside the reef.

Gonzalo is also a threat to Newfoundland, Canada. Although the hurricane will likely be declared post-tropical on Saturday, it will still have Category 1 strength winds when it makes its closest pass by Southeast Newfoundland, predicted to occur between 5 am - 8 am EDT Sunday by the 00Z Friday runs of the GFS and European models. In their 11 am EDT Friday Wind Probability Forecast, NHC gave Cape Race, Newfoundland a 64% chance of experiencing tropical storm-force winds, and a 5% chance of hurricane-force winds. Heavy rains from ex-Gonzalo are likely to be the main threat to Newfoundland.


Figure 3. Road washout at Bermuda International Airport from Category 3 Hurricane Fabian after it struck on September 5, 2003. Image credit: J.G. Howes.

Bermuda's hurricane history
Ten major hurricanes of Category 3 or stronger intensity have tracked within 75 miles of Bermuda in records dating to 1899. Two of these were Category 4 storms, the most recent of which occurred on September 13, 1948. The most recent Category 3 was Hurricane Fabian of 2003, the only hurricane to get its name retired exclusively because of its impact on the island of Bermuda. Fabian's eye passed just 14 miles (23 km) west of Bermuda on September 5, 2003 when the storm was a 120 mph (180 km/h) Category 3 hurricane. The eastern eyewall with the hurricane's strongest winds moved over the island, resulting in a direct hit; however, as the center did not move over the island, Fabian did not make landfall. According to the NHC final report, Fabian did $300 million in damage, making it the most expensive hurricane ever to hit the island. Fabian was also the first hurricane since 1926 to kill people on Bermuda; four people died when a storm surge swept over the causeway connecting the airport to the rest of the island, washing their car into the ocean. That causeway was replaced by a temporary bridge, which has remained to this day--and is of particular concern for Gonzalo's impact.

Bermuda links
Current conditions
Bermuda radar
Port of Bermuda webcam
Storm chaser Jim Edds is providing Twitter updates from Bermuda for Gonzalo


Video 1. Storm chaser Jim Edds was on Bermuda during Hurricane Fabian in 2003, and put together this 26-minute video on the experience. He is providing Twitter updates from Bermuda for Gonzalo, as well.

Strengthening Tropical Storm Ana a heavy rain threat to Hawaii
Tropical Storm Ana was at the verge of hurricane status again on Friday, with 70 mph winds. Satellite loops on Friday morning showed that Ana had its most impressive appearance yet, with a large area of heavy thunderstorms, plenty of low level spiral bands, and solid upper-level outflow to the north and east. Wind shear was light, 5 - 10 knots, and Sea Surface Temperatures (SSTs) warm, 27.4°C (81°F), which is about 1°F above average. The 8 am EDT Friday run of the SHIPS model predicted that wind shear would be light to moderate 5 - 20 knots, and ocean temperature would be warm, 27.5 - 28°C (81 - 82°F), through Saturday night. These conditions should allow Ana to slowly intensify until Saturday afternoon. Our top models for predicting hurricane tracks continue to trend farther to the west with their track for Ana, and now Kauai is the only main Hawaiian Island in the cone of uncertainty for a direct strike. In their 11 am EDT Friday Wind Probability Forecast, Central Pacific Hurricane Center (CPHC) gave Lilue on Kauai on a 32% chance of experiencing tropical storm-force winds, and a 1% chance of hurricane-force winds. Honolulu was given a 26% chance of experiencing tropical storm-force winds, and a 0% chance of hurricane-force winds. Even though it now appears that the islands will not experience major wind damage from Ana, heavy rains causing flash floods and mudslides are a major concern. Rainfall amounts of 8+ inches are possible on the Big Island, Oahu, and Kauai, according to the Friday morning runs of the GFDL and HWRF hurricane models.


Figure 4. Predicted rainfall for Ana from the GFDL model forecast made at 2 am EDT Friday October 17, 2014. The model predicted large areas of 8+ inches of rain would affect Oahu and the Big Island. Image credit: NOAA/GFDL.

Related posts
Climate Change May Increase the Number of Hawaiian Hurricanes, my August 6, 2014 post
Climatic Atlas of Tropical Cyclone Tracks over the Central North Pacific (2008)

Eastern Pacific tropical disturbance 92E a heavy rainfall threat to Mexico
In the Eastern Pacific, a well-organized area of disturbed weather (Invest 92E) was located about 150 miles south of tAcapulco, Mexico on Friday morning, and was headed north to northwest at about 5 - 10 mph. With light wind shear, warm SSTs near 29.5°C 85°F), and a moist atmosphere, this disturbance is likely to develop into a tropical depression this weekend. In their 8 am EDT Friday Tropical Weather Outlook, NHC gave 92E 2-day and 5-day odds of development of 70% and 80%, respectively. 92E is a threat to bring heavy rains to the Pacific coast of Mexico on Friday and continuing into the weekend. As of Friday morning, 92E's heavy rain had begun to push onshore, as seen on satellite loops and Acapulco radar.

Moisture from 92E may move northwards across Mexico into the southern Gulf of Mexico's Bay of Campeche by early next week, contributing to the formation of an area of low pressure that could bring heavy rains to Florida on Wednesday and Thursday, as predicted by the GFS and UKMET models.

Hurricane expert Steve Gregory has more on the tropics in a Friday morning post.

Jeff Masters

Hurricane

Category 4 Gonzalo Closes in on Bermuda; Ana Disorganized, Still a Threat to Hawaii

By: JeffMasters, 3:47 PM GMT on October 16, 2014

Hurricane Warnings are flying for Bermuda as one of the most powerful hurricanes ever to threaten the island, dangerous Category 4 Hurricane Gonzalo, aims its 145 mph winds towards Bermuda. After weakening briefly on Wednesday due to an eyewall replacement cycle, when the eye shrank to a minuscule 5 miles in diameter and the inner eyewall collapsed, Gonzalo successfully consolidated its new 20-mile diameter outer eyewall into an unbroken ring overnight. This allowed the hurricane to intensify from a Category 3 hurricane with 125 mph winds into a Category 4 hurricane with 145 mph winds overnight. That intensification process has now halted, as documented by three passes through the eye between 7 - 10:30 am EDT Thursday morning by a NOAA hurricane hunter aircraft. The plane found that the pressure had stabilized at 940 - 943 mb, a gap had opened in the southern eyewall, and a new concentric eyewall with a diameter of 40 miles had begun to form around an inner 17-mile diameter eyewall--all signs that intensification has halted. Wind shear is moderate, 10 - 15 knots, and Sea Surface Temperatures (SSTs) have cooled a bit, to 28.5°C (83°F). Infrared and visible satellite loops on Thursday morning showed an impressive well-organized major hurricane with plenty of intense heavy thunderstorms, excellent spiral banding, and solid upper-level outflow. This is not a hurricane that will weaken quickly.


Figure 1. MODIS satellite image of Hurricane Gonzalo taken at approximately 1:30 pm EDT October 16, 2014. At the time, Gonzalo had top winds of 145 mph. Image credit: NASA.

Forecast for Gonzalo
The 8 am Thursday run of the SHIPS model predicted that wind shear would remain a moderate 10 - 15 knots as Gonzalo approached Bermuda, and SSTs would cool to 27°C (81°F.) These conditions should discourage intensification, and may drive some modest weakening, but it is likely that Gonazalo will be a dangerous Category 3 or 4 storm with 120 - 135 mph winds at the time of its closest approach to Bermuda on Friday afternoon or evening. The latest suite of model runs has the hurricane passing less than 60 miles to the west of the island, which would put Bermuda in the strong right-front quadrant of the storm, potentially bringing them the strongest winds of Gonzalo's eastern eyewall. The models differ quite a bit on the forward speed on Gonzalo, with the 00Z Thursday run of the European model taking the hurricane just west of Bermuda near 10 pm AST Friday, and the GFS model predicting the closest pass at 4 pm AST Friday. Hurricane-force winds extend outwards about 45 miles from the center, and tropical storm force winds should extend 150 miles from the center. Thus, Bermuda is almost certain to see tropical storm-force winds, and pretty likely to see hurricane-force winds. In their 11 am EDT Thursday Wind Probability Forecast, NHC gave Bermuda a 99% chance of experiencing tropical storm-force winds of 39+ mph, and a 74% chance of hurricane-force winds of 74+ mph.

Gonzalo is also a threat to Newfoundland, Canada. Although the hurricane will likely be declared post-tropical on Saturday, it will still have Category 1 strength winds, and the GFS and European models predicted in their 00Z Thursday runs that Gonzalo would pass near Southeast Newfoundland between 2 am - 8 am EDT Sunday. In their 11 am EDT Thursday Wind Probability Forecast, NHC gave Cape Race, Newfoundland a 41% chance of experiencing tropical storm-force winds, and a 4% chance of hurricane-force winds.


Figure 2. Category 3 Hurricane Fabian bears down on Bermuda at 10:50 am EDT September 5, 2003. Image credit: NASA.

Bermuda's hurricane history
Ten major hurricanes of Category 3 or stronger intensity have tracked within 75 miles of Bermuda in records dating to 1899. Two of these were Category 4 storms, the most recent of which occurred on September 13, 1948. The most recent Category 3 was Hurricane Fabian of 2003, which made a direct hit on the island at Category 3 strength on September 5, 2003. According to the NHC final report, Fabian was the worst hurricane to hit Bermuda since 1926, doing $300 million in damage: "There was extensive damage to vegetation and considerable roof damage to houses in exposed locations. Some buildings had more severe damage, due to inherent structural weakness in some cases and possibly due to tornadoes (which were not confirmed) in others. There were huge (estimated 20 to 30 ft high) battering waves on the south shore of the island, with the reported storm surge estimated near 10 ft. Significant structural damage was inflicted as a result of wave action and/or surge." Fabian is the only hurricane to get its name retired exclusively because of its impact on the island of Bermuda.

Bermuda links
Current conditions
Bermuda radar
Port of Bermuda webcam
North Shore of Bermuda looking west webcam


Figure 2. MODIS satellite image of Tropical Storm Ana taken at approximately 7 pm EDT October 15, 2014. At the time, Ana had top winds of 70 mph. Image credit: NASA.

Weaker Tropical Storm Ana still a threat to Hawaii
Tropical Storm Ana was at the verge of hurricane status on Wednesday, with 70 mph winds, but increased wind shear overnight caused the storm to weaken and grow disorganized. Satellite loops on Thursday morning showed that Ana had recovered somewhat, with more heavy thunderstorms blossoming near its center, but mircrowave satellite images from the Navy Research Lab in Monterey show that Ana has nothing resembling an eyewall attempting to form, and it is unlikely that Ana can intensify into a hurricane on Thursday. Wind shear is light, 5 - 10 knots, and Sea Surface Temperatures (SSTs) are warm, 28°C (82°F), which is about 1°F above average. The 8 am EDT Thursday run of the SHIPS model predicted that wind shear would be light, 5 - 10 knots, and ocean temperature would be warm, 27.5 - 28°C (81 - 82°F) for the next three days along Ana's path, and gave a 19% chance that the storm would intensify by 35 mph into a Category 1 hurricane by Friday morning. It is more likely that Ana would become a hurricane on Friday evening, though, given the storm's disorganized condition on Thursday morning. Our top two models for predicting hurricane tracks, the GFS and European models, both showed in their 00Z Thursday runs Ana passing 100 - 200 miles west of the Big Island of Hawaii on Saturday morning. This is far enough away that the tall mountains of the island would likely be unable to disrupt the storm. In their 11 am EDT Thursday Wind Probability Forecast, Central Pacific Hurricane Center (CPHC) gave Kailua-Kona on the Big Island a 49% chance of experiencing tropical storm-force winds, and a 4% chance of hurricane-force winds. Honolulu was given a 46% chance of experiencing tropical storm-force winds, and a 3% chance of hurricane-force winds. With the model runs for Ana trending farther west of late, Kauai appears to the be the island most at risk of a direct hit, but the storm should be weakening by the time it reaches Kauai Sunday evening, due to higher wind shear.


Figure 2. Tracks of all tropical cyclones (tropical depressions, tropical storms, and hurricanes) to pass within 100 miles of the Hawaiian Islands, 1949 - 2014. Hurricanes approaching from the east typically fall apart before they reach Hawaii due to the cool waters and dry air that lie to the east of the islands. Only two named storms approaching from the east have hit the islands since 1949, an unnamed 1958 tropical storm and Tropical Storm Iselle of 2014, which hit the Big Island. Hurricanes approaching from the south represent the biggest danger to the islands, due to the warmer waters and more unstable air present to the south. The only two major hurricanes to have affected the islands since 1949, Hurricane Iniki of 1992 and Hurricane Dot of 1959, both came from the south. Image credit: NOAA/CSC.

Hawaii's hurricane history
Tropical storms and hurricanes are rare in the Hawaiian Islands, but 2014 is one of their most active years on record. Tropical Storm Iselle made a direct hit on August 8, Hurricane Julio passed just to the north of the islands a few days later, bringing high surf, and now Hurricane Ana threatens to cause more trouble. Since 1949, the Hawaiian Islands have received a direct hit from just two hurricanes--Dot in 1959, and Iniki in 1992. Both hit the island of Kauai. Only two tropical storms have hit the islands since 1949--an unnamed 1958 storm which hit the Big Island, and Tropical Storm Iselle, which made landfall along the southeast shore of Hawaii's Big Island on August 8, 2014 with 60 mph winds. On average, between four and five tropical cyclones are observed in the Central Pacific every year. This number has ranged from zero, most recently as 1979, to as many as eleven in 1992 and 1994. August is the peak month, followed by July, then September. A brief summary of the three most significant hurricanes to affect Hawaii in modern times:

September 1992: Hurricane Iniki was the strongest, deadliest, and most damaging hurricane to affect Hawaii since records began. It hit the island of Kauai as a Category 4 on September 11, killing six and causing $2 billion in damage.

November 1982: Hurricane Iwa was one of Hawaii's most damaging hurricanes. Although it was only a Category 1 storm, it passed just miles west of Kauai, moving at a speed of nearly 50 miles per hour (80 km/h). Iwa killed one person and did $250 million in damage, making it the second most damaging hurricane to ever hit Hawaii. All the islands reported some surf damage along their southwest facing shores, and wind damage was widespread on Kauai.

August 1959: Hurricane Dot entered the Central Pacific as a Category 4 hurricane just south of Hawaii, but weakened to a Category 1 storm before making landfall on Kauai. Dot brought sustained winds of 81 mph with gusts to 103 mph to Kilauea Light. Damage was in excess of $6 million. No Dot-related deaths were recorded.

Related posts
Climate Change May Increase the Number of Hawaiian Hurricanes, my August 6, 2014 post
Climatic Atlas of Tropical Cyclone Tracks over the Central North Pacific (2008)

Eastern Pacific tropical disturbance 92E a heavy rainfall threat to Mexico
In the Eastern Pacific, an broad area of disturbed weather (Invest 92E) was located a few hundred miles south of the Pacific coast of Mexico on Thursday morning, and was headed northwest at about 5 - 10 mph. With light wind shear, warm SSTs near 29.5°C 85°F), and a moist atmosphere, this disturbance is likely to develop into a tropical depression later this week. In their 8 am EDT Thursday Tropical Weather Outlook, NHC gave 92E 2-day and 5-day odds of development of 60% and 70%, respectively. 92E is a threat to bring heavy rains to the Pacific coast of Mexico on Friday and continuing into the weekend. As of Thursday morning, though, 92E's heavy rains remained offshore, as seen on satellite loops.

Moisture from 92E may move northwards across Mexico into the southern Gulf of Mexico's Bay of Campeche by early next week, contributing to the formation of a tropical or sub-tropical depression there by Wednesday, as predicted by the GFS and European models.

Hurricane expert Steve Gregory has more on the tropics in a Thursday post.

Jeff Masters

Hurricane

Gonzalo the Atlantic's First Category 4 Hurricane Since 2011; Ana Takes Aim at Hawaii

By: JeffMasters, 4:30 PM GMT on October 15, 2014

A Hurricane Watch is up for Bermuda as Powerful Category 4 Hurricane Gonzalo aims its 130 mph winds towards the island. Gonzalo is the Atlantic's first Category 4 hurricane since October 2, 2011, when Hurricane Ophelia reached 140 mph winds. Gonzalo walloped the northernmost Lesser Antilles Islands on Monday into Tuesday morning while rapidly intensifying from a tropical storm to a strong Category 1 hurricane. One person was killed on St. Maarten, and two others were missing--one in St. Martin and one in St. Barths, according to The Daily Herald. Twelve people were injured in Antigua.


Figure 1. People clear trees from the road in the aftermath of Hurricane Gonzalo on October 14, 2014 on the French Caribbean island of Saint Martin. Photo credit: STRINGER/AFP/Getty Images.

Forecast for Gonzalo
Data from an Air Force hurricane hunter mission and satellite loops on Wednesday morning showed that Gonzalo had a tiny 6-mile diameter inner eye, with a concentric 28-mile diameter outer eyewall forming. The inner eyewall will likely collapse by Wednesday evening and the outer eyewall will take over as the main eyewall in an eyewall replacement cycle. This process should halt intensification, and possibly reduce Gonzalo to Category 3 status by Wednesday evening. But with wind shear a light 5 - 10 knots and warm Sea Surface Temperatures (SSTs) near 29°C (84°F), Gonzalo should be able to stay a major hurricane into Thursday. If Gonzalo is able to complete its eyewall replacement cycle quickly, the hurricane could re-intensify some and be a Category 4 storm into Friday morning. It is more likely, though that Gonzalo reached its peak lifetime intensity at 11 am EDT Wednesday, as the official NHC forecast indicates. Water vapor satellite loops show some dry air getting wrapped into the storm, which will interfere with intensification. The 8 am Wednesday run of the SHIPS model predicted that by Friday morning, when Gonzalo will make its closest pass by Bermuda, wind shear would increase to 10 - 15 knots and SSTs would cool to 27°C (81°F.) This should discourage intensification, and may drive steady weakening. The models have come into better agreement on the track of Gonzalo, with our two top track models, the GFS and European, predicting in their 00Z Wednesday runs that the hurricane would pass 50 - 100 miles west of Bermuda between 8 am - 2 pm EDT Friday. At that time, hurricane-force winds should extend outwards about 35 - 45 miles from the center, and tropical storm force winds should extend 160 - 170 miles from the center. Thus, Bermuda is likely to see tropical storm-force winds, but not hurricane-force winds. In their 11 am EDT Wednesday Wind Probability Forecast, NHC gave Bermuda a 94% chance of experiencing tropical storm-force winds of 39+ mph, and a 37% chance of hurricane-force winds of 74+ mph. Keep in mind that the average error in a 2-day NHC Atlantic track forecast between 2008 - 2012 was 90 miles.

Gonzalo is also a threat to Newfoundland, Canada; the GFS and European models predicted in their 00Z Wednesday runs that Gonzalo would hit Newfoundland between 8 - 11 pm EDT Saturday. In their 11 am EDT Wednesday Wind Probability Forecast, NHC gave Cape Race, Newfoundland a 55% chance of experiencing tropical storm-force winds, and a 7% chance of hurricane-force winds.


Figure 2. MODIS satellite image of Tropical Storm Ana taken at approximately 7 pm EDT October 14, 2014. At the time, Ana had top winds of 65 mph. Image credit: NASA.

Tropical Storm Ana takes aim at Hawaii
Tropical Storm Ana was at the verge of hurricane status at 11 am EDT Wednesday, and represents a potential serious rain, wind, and storm surge threat to the Hawaiian Islands this weekend. Satellite loops show that Ana has a Central Dense Overcast (CDO) of high cirrus clouds, characteristic of an intensifying tropical storm close to reaching hurricane status. Wind shear is light, 5 - 10 knots, and Sea Surface Temperatures (SSTs) are warm, 28°C (82°F), which is about 1°F above average. The 8 am EDT Wednesday run of the SHIPS model predicted that wind shear would be light, 5 - 10 knots, and ocean temperature would be warm, 27.5 - 28°C (81 - 82°F) for the next three days along Ana's path, and gave a 26% chance that the storm would intensify by 35 mph into a Category 2 hurricane by Thursday morning. Our top two models for predicting hurricane tracks, the GFS and European models, both show Ana passing very close to the Big Island of Hawaii on Saturday morning, and it is possible that the island could experience tropical storm conditions for the second time this year. In their 11 am EDT Wednesday Wind Probability Forecast, Central Pacific Hurricane Center (CPHC) gave Kailua-Kona on the Big Island a 60% chance of experiencing tropical storm-force winds, and a 9% chance of hurricane-force winds. Honolulu was given a 44% chance of experiencing tropical storm-force winds, and a 4% chance of hurricane-force winds. The average error in a 3-day NHC Eastern Pacific track forecast between 2008 - 2012 was 117 miles, and the 2-day error was 82 miles. The Central Pacific Hurricane Center, which is making the forecasts for Ana, does not post its error numbers, but they are probably similar. Steering currents are expected to weaken as Ana approaches Hawaii, so the 3 - 5 forecast probably has higher errors than usual. Ana could very well miss making a direct hit on any of the Hawaiian Islands, passing 100 - 200 miles to the west, if the latest 00Z Wednesday forecast from the European model is correct.


Figure 3. Radar image from the South Hawaii radar at 7:49 am EDT August 8, 2014 of Tropical Storm Iselle near landfall on the Big Island. The radar beam is being intercepted by the high mountains of Hawaii, and cannot "see" to the northwest.

First Iselle and Julio for Hawaii, and now Ana?
Tropical storms and hurricanes are rare in the Hawaiian Islands, but 2014 is one of their most active years on record. Tropical Storm Iselle made a direct hit on August 8, Hurricane Julio passed just to the north of the islands a few days later, bringing high surf, and now Hurricane Ana threatens to cause more trouble. Since 1949, the Hawaiian Islands have received a direct hit from just two hurricanes--Dot in 1959, and Iniki in 1992. Both hit the island of Kauai. Only two tropical storms have hit the islands since 1949--an unnamed 1958 storm which hit the Big Island, and Tropical Storm Iselle, which made landfall along the southeast shore of Hawaii's Big Island on August 8, 2014 with 60 mph winds. Iselle killed one person and did $66 million in damage, according to Aon Benfield. Most of this damage ($53 million) came from the destruction of 60% of the state's papaya crop. Iselle was the strongest tropical cyclone on record to hit the Big Island; the island's other tropical storm, the unnamed 1958 storm, had sustained winds of 50 mph at landfall. (Older records from the Central Pacific Hurricane Center show at least one other tropical cyclone between 1900 - 1948 that probably made a direct hit on Hawaii: an August 19, 1938 storm that brought sustained winds of 60 mph to Oahu.)

Eastern Pacific tropical disturbance 92E a heavy rainfall threat to Mexico
In the Eastern Pacific, an broad area of disturbed weather (Invest 92E) was located a few hundred miles south of the Pacific coast of Mexico on Wednesday morning, and was headed northwest at about 5 - 10 mph. With light wind shear, warm SSTs near 29.5°C (85°F), and a moist atmosphere, this disturbance is likely to develop into a tropical depression later this week. In their 8 am EDT Wednesday Tropical Weather Outlook, NHC gave 92E 2-day and 5-day odds of development of 40% and 60%, respectively. 92E is a threat to bring heavy rains to the Pacific coast of Mexico on Thursday and continuing into the weekend. As of Wednesday morning, though, 92E's heavy rains remained offshore, as seen on satellite loops.

Moisture from 92E may move northwards across Mexico into the southern Gulf of Mexico's Bay of Campeche by early next week, contributing to the formation of a tropical or sub-tropical depression there by Wednesday, as predicted by the GFS and European models.

Hurricane expert Steve Gregory has more on the tropics in a Wednesday afternoon post.

Jeff Masters

Hurricane

Hurricane Gonzalo Leaves the Lesser Antilles; Hawaii at Risk From Tropical Storm Ana

By: JeffMasters, 1:23 PM GMT on October 14, 2014

Intensifying Category 2 Hurricane Gonzalo is heading northwest at 13 mph away from Puerto Rico and the Virgin Islands after plowing through the northernmost Lesser Antilles Islands overnight, bringing Category 1 hurricane conditions. The storm passed over Antigua Island between 10 am - 11 am AST on Monday, and Antigua recorded sustained winds of 67 mph gusting to 88 mph late Monday morning. Winds at nearby Barbuda were sustained at 60 mph, gusting to 70 mph, at 1:54 pm AST. St. Martin had sustained winds of 39 mph, gusting to 64 mph, at 7 pm AST, before the station stopped reporting. St. Maartin recorded sustained winds of 63 mph, gusting to 75 mph Monday evening. A Personal Weather Station (PWS) on St. Barthelemy recorded sustained winds of 82 mph, gusting to 108 mph, between 3 - 5 pm AST Monday. Gonzalo became the sixth hurricane of the 2014 Atlantic hurricane season at 5 pm Monday. Although Gonzalo's formation into a tropical storm on October 12 came nearly a month later than the typical September 16 date for formation of the season's seventh named storm, we are now ahead of schedule for hurricanes--a typical hurricane season has only six hurricanes, with the last one usually occurring in November.


Figure 1. Long range Puerto Rico radar image of Hurricane Gonzalo taken at 8:23 am EDT October 14, 2014. Gonzalo's outermost rain bands were still affecting the Virgin Islands.


Figure 2. MODIS satellite image of Hurricane Gonzalo taken at approximately 10:30 am EDT October 14, 2014, as the storm was pulling away from the Virgin Islands. At the time, Gonzalo had top winds of 110 mph. Image credit: NASA.

Forecast for Gonzalo
Satellite loops showed on Tuesday morning that Gonzalo was well-organized, with plenty of low-level spiral bands and heavy thunderstorm activity, and an eye that was growing more prominent. With wind shear a moderate 10 - 15 knots and warm Sea Surface Temperatures (SSTs) near 29°C (84°F), Gonzalo should continue to intensify on Tuesday. The 8 am Tuesday run of the SHIPS model predicted that conditions would remain favorable for development through Thursday, with light to moderate wind shear and SSTs remaining near 29°C (84°F). By Wednesday, Gonzalo has a good chance of becoming the Atlantic's first Category 4 hurricane since October 2, 2011, when Hurricane Ophelia reached 140 mph winds. By Thursday night and Friday morning, Gonzalo will encounter high wind shear, cooler SSTs of 28°C (81°F), and dryer air, which should drive steady weakening. During Gonzalo's closest pass by Bermuda on Friday, the hurricane could be anywhere between a Category 1 and Category 3 storm. Our two top models for predicting hurricane track, the GFS and European, differed considerably with their 00Z Tuesday runs on how fast Gonzalo would accelerate towards Bermuda on Friday. The European model predicted that Gonzalo would pass within 80 miles of the island near midnight EDT Friday night, while the GFS model had Gonzalo passing within 30 miles at 11 am EDT Friday.

Brian McNoldy of the Univ. of Miami, Rosenstiel School, has put together some great radar loops of Gonzalo, Hudhud, and Vongfong here.


Figure 3. Latest satellite image of Tropical Storm Ana.

Hawaii needs to pay attention to Tropical Storm Ana
In the Central Pacific, Tropical Storm Ana has formed, and was located about 900 miles east-southeast of the Big Island of Hawaii on Tuesday morning. Ana is headed northwest at 7 mph towards Hawaii. Satellite loops show that Ana has developed a Central Dense Overcast (CDO) of high cirrus clouds, characteristic of an intensifying tropical storm on its way to reaching hurricane status. The 8 am EDT Tuesday run of the SHIPS model predicted that wind shear would be light to moderate, 5 - 15 knots, and ocean temperature would be warm, 27 - 28.5°C (81 - 83°F) for the next five days along Ana's path, with some modest drying of the atmosphere. These conditions favor development, and I expect Ana will be able to reach Category 2 hurricane strength by Thursday. Our top two models for predicting hurricane tracks, the GFS and European models, both show Ana passing very close to the Big Island of Hawaii this weekend, and it is possible that the island could experience tropical storm conditions for the second time this year.

Hurricane expert Steve Gregory has more on the tropics in a Tuesday afternoon post.

Jeff Masters

Hurricane

Gonzalo Near Hurricane Strength; 24 Dead, $1.6 Billion in Damage in India From Hudhud

By: JeffMasters, 3:40 PM GMT on October 13, 2014

Hurricane warnings are flying in the British Virgin Islands as strengthening Tropical Storm Gonzalo marches west-northwest at 10 mph though the northernmost Lesser Antilles Islands. The storm passed over Antigua Island between 10 am - 11 am AST on Monday, and sustained winds at Antigua hit 45 mph at 7 am AST before the station stopped reporting. NHC is still able to get wind information from the island, and the island reported a sustained wind of 67 mph gusting to 88 mph late Monday morning. Winds at nearby Barbuda were sustained at 43 mph gusting to 61 mph at 1 pm AST. Satellite loops showed on Monday morning that Gonzalo was growing increasingly well-organized, with more low-level spiral bands and heavy thunderstorm activity. A Central Dense Overcast (CDO) of high cirrus clouds was apparent on visible satellite imagery, the sign of an intensifying tropical storm about to reach hurricane status. Guadaloupe radar showed that Gonzalo was close to closing off an eye, which should allow for more rapid intensification of the storm by Monday evening. Water vapor satellite loops showed a good degree of dry air surrounding Gonzalo, but with wind shear a light 5 - 10 knots, this dry air was not substantially impeding development. Sea Surface Temperatures (SSTs) were warm, near 29°C (84°F). The 8 am Monday run of the SHIPS model predicted that conditions would remain favorable for development for the next four days, with light to moderate wind shear and SSTs near 29°C (84°F). Gonzalo should steadily intensify through the week, and has the potential to be a major Category 3 hurricane by Friday. The models are unified in showing that the storm will get caught up in a trough of low pressure and turn to the northwest on Tuesday and north by Wednesday, though our two top models, the GFS and European, are widely divergent on their prediction on how fast Gonzalo will get pulled to the north towards Bermuda. The GFS predicts that the storm will make its closest pass by the island on Friday night, while the European model delays Gonzalo's arrival until Sunday.


Figure 1. Guadaloupe radar image of Tropical Storm Gonzalo taken at 11:15 am EDT October 13, 2014. Gonzalo was close to closing off an eye, which should allow for more rapid intensification of the storm by Monday evening. Image credit: Meteo France.


Figure 2. MODIS satellite image of Tropical Storm Gonzalo taken at approximately 1 pm EDT October 13, 2014, as the storm was passing through the Lesser Antilles Islands. At the time, Gonzalo had top winds of 70 mph. Image credit: NASA.

Fay dying
Tropical Storm Fay was racing east at 29 mph late Monday morning out to sea after battering Bermuda on Sunday with winds close to hurricane force. Sustained winds at the Bermuda Airport reached 61 mph, with a gust to 82 mph, at 7:34 am local time Sunday morning. The airport recorded 1.85" of rain from the storm. Fay is being absorbed by a cold front and will likely be declared post-tropical by Monday evening.


Figure 3. MODIS satellite image of Tropical Cyclone Hudhud taken at approximately 1 am EDT October 12, 2014, as the storm was making landfall near Visakhapatnam, India. At the time, Hudhud was a Category 4 storm with 135 mph winds. Image credit: NASA.

Heavy damage in India from Category 4 Hudhud
Tropical Cyclone Hudhud has dissipated after it powered ashore near Visakhapatnam in the Andhra Pradesh state of India at 05 UTC (3 am EDT) Sunday as a Category 4 storm with sustained winds of 135 mph. At least 24 deaths are being blamed on the cyclone: 21 in Andhra Pradesh, and 3 in the neighboring Odisha state. Preliminary damage estimates are at least $1.64 billion (Rs 10,000 crore), with the heaviest damage in Visakhapatnam, a port city of 2 million, which received a direct hit. One-minute resolution wind observations from Visakhapatnam showed a peak sustained wind of 73 mph at 9:44 am local time Sunday, with a peak gust of 119 mph at 10:30 am. The station stopped reporting data at that time. According to EM-DAT, the International Disaster Database, Hudhud's preliminary $1.6 billion price tag would make it the 2nd most expensive tropical cyclone in India's history, behind the October 28, 1999 Orissa Cyclone, which killed 9,843 people and did $2.5 billion in damage (1999 dollars.) India has had just one other billion-dollar tropical cyclone disaster, the November 8, 1996 cyclone that killed 708 and did $1.5 billion in damage (1996 dollars.) Just last month, India had its most expensive natural disaster in history, when torrential monsoon rains of over 12" (305 mm) lashed the India-Pakistan border region of Kashmir and Jammu Provinces on September 3 - 7, triggering devastating floods that swept through the mountainous region, killing over 600 people and doing $16+ billion in damage, as estimated by insurance broker Aon Benfield. India's previous most expensive natural disaster was the $11.6 billion (2014 dollars) in damage from the July 1993 monsoon floods.


Figure 4. Heavy rains from Vongfong as seen on Japanese radar at 22:45 local time Monday (9:45 am EDT.) Image credit: Japan Meteorological Agency.

Vongfong drenching Japan
Tropical Storm Vongfong made landfall at 8:30 am JST Monday near Makurazaki City, Kagoshima Prefecture, Kyushu Island, Japan according to the Japan Meteorological Agency (JMA.) They rated it a Category 1 typhoon with 75 mph at landfall, while the U.S. Joint Typhoon Warning Center (JTWC) rated Vongfong a tropical storm with 60 mph winds. Monday morning at 8 am EDT, Vongfong was racing northeast at 31 mph, and was centered about 100 miles west of Tokyo. Vongfong has injured at least 61 people in Japan, and dumped heavy rains of 1 - 2 feet. Japanese radar shows that Vongfong is still a major rain-maker, and the storm will likely dump up to a foot of rain over portions of Japan over the next day. Evacuation advisories were issued in populated areas flanking the Mount Ontake volcano, which fatally erupted two weeks ago, killing 56 people. Heavy rains from Vongfong may cause mudslides caked with volcanic ash along the flanks of the volcano.

Hawaii needs to pay attention to tropical disturbance 95C
In the Central Pacific, an area of disturbed weather (Invest 95C) located about 1000 miles east-southeast of the Big Island of Hawaii on Monday morning is headed west-northwest at 10 mph towards Hawaii. Satellite loops show that 95C is well-organized with an increasing amount of heavy thunderstorm activity. The 8 am EDT Monday run of the SHIPS model predicted that wind shear would be low, 5 - 10 knots, and ocean temperature would be warm, 27 - 28.5°C (81 - 83°F) for the next five days along 95C's path, but that the atmosphere would dry considerably. These conditions favor development. In their 8 am EDT Monday Tropical Weather Outlook, the Central Pacific Hurricane Center gave 95C 2-day odds of development of 80%. Our top two models for predicting hurricane tracks, the GFS and European models, both show 95C passing very close to the Big Island of Hawaii on Saturday, and it is possible that the island could experience tropical storm conditions for the second time this year.


Figure 5. NOAA's Storm Prediction Center (SPC) has put portions of seven Mississippi Valley states in their "Moderate Risk" for severe weather on Monday.

Moderate risk of severe weather today
An unusually amplified jet stream pattern over the center of the U.S. will bring severe weather on Monday. NOAA's Storm Prediction Center (SPC) has put portions seven states along the Mississippi River in their "Moderate Risk" for severe weather, with damaging winds from severe thunderstorms the primary threat--though a few tornadoes and some large hail will also likely occur. A suspected tornado ripped through Ashdown, Arkansas early Monday morning, killing one person and injuring three others.

Hurricane expert Steve Gregory has his take on the tropics in a <

Jeff Masters

Hurricane

Gonzalo Forms Near Lesser Antilles; Hudhud Blasts India; Fay Lashes Bermuda

By: JeffMasters, 7:37 PM GMT on October 12, 2014

For the first time since 2013, the National Hurricane Center (NHC) is issuing simultaneous advisories for two Atlantic named storms, thanks to the formation of Tropical Storm Gonzalo on Sunday afternoon. Satellite loops and Martinique radar showed on Sunday afternoon that Gonzalo was well-organized with plenty of spin, spiral bands, and a modest amount of heavy thunderstorm activity that was increasing in areal extent and intensity. Water vapor satellite loops showed a good degree of dry air surrounding Gonzalo, but with wind shear a light 5 - 10 knots, this dry air was not substantially impeding development. Sea Surface Temperatures (SSTs) were warm, near 29°C (84°F). The 2 pm Sunday run of the SHIPS model predicted that conditions would remain favorable for development for the next five days, with light to moderate wind shear and SSTs near 29°C (84°F). Gonzalo should steadily intensify until reaching Puerto Rico on Monday. After that time, the models are unified in showing that the storm will get caught up in a trough of low pressure and turn to the north and then northeast, possibly passing close to Bermuda next Saturday or Sunday.


Figure 1. MODIS satellite image of Tropical Gonzalo taken at approximately 12 pm EDT October 12, 2014, as the storm was forming. Image credit: NASA.


Figure 2. Martinique radar image of Tropical Gonzalo taken at 3:15 pm EDT October 12, 2014. Image credit: Meteo France.

Fay brings winds near hurricane force to Bermuda
Tropical Storm Fay is accelerating to the northeast, out to sea, after battering Bermuda with winds close to hurricane force. Sustained winds at the Bermuda Airport reached 61 mph, with a gust to 82 mph, at 7:34 am local time Sunday morning. The airport recorded 1.85" of rain from the storm as of noon on Sunday. Fay will be absorbed by a cold front on Monday and die, without affecting any other land areas. The construction on Bermuda is the best of any island in the Atlantic to handle hurricane-force winds, and I expect damage on the island will be minor.

Category 4 Hudhud blasts India
Tropical Cyclone Hudhud powered ashore near Visakhapatnam, India at 05 UTC (3 am EDT) Sunday as a Category 4 storm with sustained winds of 135 mph. Preliminary media reports indicate that damage was heavy in Visakhapatnam, a port city of 2 million, with thousands of homes damaged or destroyed and five people killed by falling trees and masonry. One-minute resolution wind observations from Visakhapatnam showed a peak sustained wind of 73 mph at 9:44 am local time, with a peak gust of 119 mph at 10:30 am. The station stopped reporting data at that time. Communications are out to much of the most severely affected regions, and I expect Hudhud's eventual toll will be similar to that of Category 4 Tropical Cyclone Phailin, which killed 45 people and did $700 million in damage in October 2013 to an area of India's coast just north of where Hudhud hit. Satellite loops show that Hudhud is pushing inland and weakening rapidly, with the storm's heavy thunderstorms steadily shrinking in areal coverage and intensity.


Figure 3. MODIS satellite image of Tropical Cyclone Hudhud taken at approximately 1 am EDT October 12, 2014, as the storm was making landfall near Visakhapatnam, India. At the time, Hudhud was a Category 4 storm with 135 mph winds. Image credit: NASA.


Figure 4. Final image of Tropical Cyclone Hudhud as seen by radar out of Visakhapatnam, India before it failed at 4:51 UTC (12:51 am EDT) October 12, 2014. At the time, Hudhud was a Category 4 storm with 135 mph winds.

Vongfong drenching Japan
Heavy rains from Tropical Storm Vongfong are drenching southern Japan as the once-mighty typhoon steams slowly north-northeastwards at 10 mph. Okinawa Island took a tremendous beating from Vongfong on Friday and Saturday, with sustained winds reaching 64 mph, with gusts as high as 89 mph. The Japan Meteorological Agency (JMA) AMeDAS site at Kunigami on the northern end of Okinawa reported 20.83" (529.0 mm) of rain in 48 hours. Vongfong injured at least 31 people and knocked out power to much of the island. Satellite loops and Japanese radar show that Vongfong's eyewall has collapsed, and the storm continues to weaken due to high wind shear and cooling waters. Vongfong will likely dump 1 - 2 feet of rain over portions of Japan Sunday and Monday.


Figure 5. Heavy rains from Vongfong as seen on Japanese radar at 01:25 local time Monday (12:25 pm EDT Sunday.) Image credit: Japan Meteorological Agency.

Hurricane expert Steve Gregory has his take on the tropics in a Sunday afternoon post.

Jeff Masters

Hurricane

90L Likely a Tropical Depression; Category 4 Hudhud Blasts India; Fay Lashes Bermuda

By: JeffMasters, 4:52 PM GMT on October 12, 2014

An area of disturbed weather associated with a tropical wave located about 200 miles east of the northern Lesser Antilles Islands on Sunday morning (Invest 90L) was headed west at about 10 - 15 mph, and is probably already a tropical depression. Satellite loops and Martinique radar showed 90L was well-organized with plenty of spin, spiral bands, and a modest amount of heavy thunderstorm activity. Water vapor satellite loops show a good degree of dry air surrounding 90L, and this dry air is retarding development. Sea Surface Temperatures (SSTs) were warm, near 28.5°C (83°F), and wind shear was light, 5 - 10 knots. These conditions are favorable for steady development. The 8 am Sunday run of the SHIPS model predicted that conditions would remain favorable for development for the next five days, with light to moderate wind shear and SSTs near 29°C (84°F). In a special 10:30 am EDT Sunday Tropical Weather Outlook, NHC gave 90L 2-day and 5-day development odds of 90%. 90L's west to west-northwest trajectory over the next few days will bring heavy rains over the northern Lesser Antilles Islands on Sunday evening, and these rains will spread westwards to the Virgin Islands and Puerto Rico by Monday morning, and to the eastern Dominican Republic on Monday evening. Interaction with the high terrain of Puerto Rico and Hispaniola may slow down development on Monday and Tuesday. The storm's center will be near Puerto Rico on Monday, and near the Southeast Bahamas and Turks and Caicos Islands by Wednesday. After that time, the models are unified in showing that 90L will get caught up in a trough of low pressure and turn to the north and then northeast, possibly passing close to Bermuda next Saturday or Sunday. An Air Force hurricane hunter aircraft is in the air, and will be investigating 90L on Sunday afternoon.


Figure 1. Latest satellite image of Invest 90L near the Lesser Antilles.

Fay brings winds near hurricane force to Bermuda
Tropical Storm Fay is accelerating to the northeast, out to sea, after battering Bermuda with winds close to hurricane force. Sustained winds at the Bermuda Airport reached 61 mph, with a gust to 82 mph, at 7:34 am local time Sunday morning. The airport recorded 1.85" of rain from the storm as of noon on Sunday. Fay will be absorbed by a cold front on Monday and die, without affecting any other land areas. The construction on Bermuda is the best of any island in the Atlantic to handle hurricane-force winds, and I expect damage on the island will be minor.

Category 4 Hudhud blasts India
Tropical Cyclone Hudhud powered ashore near Visakhapatnam, India at 05 UTC (3 am EDT) Sunday as a Category 4 storm with sustained winds of 135 mph. Preliminary media reports indicate that damage was heavy in Visakhapatnam, a port city of 2 million, with thousands of homes damaged or destroyed and five people killed by falling trees and masonry. One-minute resolution wind observations from Visakhapatnam showed a peak sustained wind of 73 mph at 9:44 am local time, with a peak gust of 119 mph at 10:30 am. The station stopped reporting data at that time. Communications are out to much of the most severely affected regions, and I expect Hudhud's eventual toll will be similar to that of Category 4 Tropical Cyclone Phailin, which killed 45 people and did $700 million in damage in October 2013 to an area of India's coast just north of where Hudhud hit. Satellite loops show that Hudhud is pushing inland and weakening rapidly, with the storm's heavy thunderstorms steadily shrinking in areal coverage and intensity.


Figure 2. MODIS satellite image of Tropical Cyclone Hudhud taken at approximately 1 am EDT October 12, 2014, as the storm was making landfall near Visakhapatnam, India. At the time, Hudhud was a Category 4 storm with 135 mph winds. Image credit: NASA.


Figure 3. Final image of Tropical Cyclone Hudhud as seen by radar out of Visakhapatnam, India before it failed at 4:51 UTC (12:51 am EDT) October 12, 2014. At the time, Hudhud was a Category 4 storm with 135 mph winds.


Video 1. Footage of high winds and heavy rain affecting Visakhapatnam, India as Tropical Cyclone Hudhud approaches the city on October 11, 2014.

Vongfong drenching Japan
Heavy rains from Tropical Storm Vongfong are drenching southern Japan as the once-mighty typhoon steams slowly north-northeastwards at 10 mph. Okinawa Island took a tremendous beating from Vongfong on Friday and Saturday, with sustained winds reaching 64 mph, with gusts as high as 89 mph. The Japan Meteorological Agency (JMA) AMeDAS site at Kunigami on the northern end of Okinawa reported 20.83" (529.0 mm) of rain in 48 hours. Vongfong injured at least 31 people and knocked out power to much of the island. Satellite loops and Japanese radar show that Vongfong's eyewall has collapsed, and the storm continues to weaken due to high wind shear and cooling waters. Vongfong will likely dump 1 - 2 feet of rain over portions of Japan Sunday and Monday.


Figure 4. Heavy rains from Vongfong as seen on Japanese radar at 01:25 local time Monday (12:25 pm EDT Sunday.) Image credit: Japan Meteorological Agency.

Hurricane expert Steve Gregory has his take on the tropics in a Sunday afternoon post.

Jeff Masters

Hurricane

Fay Skirts Bermuda; Vongfong Pounds Okinawa; Hudhud Bearing Down on India

By: Jeff Masters , 5:13 PM GMT on October 11, 2014

Tropical Storm Fay is here, the sixth named storm of this quiet 2014 Atlantic hurricane season. Fay's formation date of October 10 comes just over a month later than the typical September 8 formation date for the season's sixth named storm. Bermuda is the only land area Fay poses a threat to, and the 11 am EDT Saturday Wind Probability Forecast from NHC gave Bermuda an 87% chance of seeing tropical storm-force winds of 39+ mph, with the strongest winds expected to affect the island Saturday evening into Sunday morning. Satellite loops on Saturday morning showed the typical view of a tropical storm experiencing high wind shear, with a surface circulation nearly exposed to view, and the heavy thunderstorms restricted to one quadrant--to the northwest. Sea Surface Temperatures (SSTs) were warm, near 29°C (84°F), and wind shear was high, 20 - 25 knots. Fay will recurve to the northeast out to sea on Sunday without troubling any other land areas.


Figure 1. Latest satellite image of Tropical Storm Fay.

Invest 90L will bring heavy rains to the Lesser Antilles
An area of disturbed weather associated with a tropical wave located about 400 miles east of the northern Lesser Antilles Islands on Saturday morning (Invest 90L) was headed west-northwest at about 10 mph. Satellite loops showed 90L had a modest amount of spin and heavy thunderstorm activity, and these thunderstorms were beginning to grow more organized. Water vapor satellite loops show a good degree of dry air surrounding 90L, and this dry air is retarding development. Sea Surface Temperatures (SSTs) were warm, near 28.5°C (83°F), and wind shear was moderate, 10 - 20 knots. These conditions are favorable for slow development. The 8 am Saturday run of the SHIPS model predicted that conditions would remain favorable for slow development through Monday, with light to moderate wind shear and SSTs near 29°C (84°F)--though the atmosphere is expected to dry as the disturbance moves past Puerto Rico on Monday. Two of our three of our reliable computer models for predicting tropical storm formation--GFS and UKMET models--showed 90L developing by the middle of next week in their 12Z and 00Z Saturday runs, respectively. When multiple models predict development, the odds of formation are increased. In their 8 am EDT Saturday Tropical Weather Outlook, NHC gave 90L 2-day and 5-day development odds of 20% and 60%, respectively. 90L's west-northwest trajectory will bring heavy rains over the northern Lesser Antilles Islands on Sunday, and these rains will spread westwards to the Virgin Islands and Puerto Rico by Sunday night, and to the eastern Dominican Republic on Monday. Interaction with the high terrain of Puerto Rico and Hispaniola may slow down development on Monday and Tuesday. The storm's center will be near Puerto Rico on Monday, and near the Southeast Bahamas and Turks and Caicos Islands by Wednesday. After that time, the vast majority of the members of the GFS and European ensemble model show 90L getting caught up in a trough of low pressure and scooting to the north and then northeast, possibly putting Bermuda at risk. An Air Force hurricane hunter aircraft has been tasked to investigate 90L on Sunday afternoon.


Figure 2. Latest satellite image of Invest 90L near the Lesser Antilles.

Dangerous Tropical Cyclone Hudhud approaching India
Category 3 Tropical Cyclone Hudhud in the Bay of Bengal continues to steadily intensify as it heads west-northwest at 7 mph towards India, with sustained winds estimated at 125 mph at 8 am EDT Saturday. Wind shear has fallen to a moderate 10 - 15 knots, and Hudhud is over very warm waters of 30.5°C (87°F)--conditions which favor continued intensification until landfall. Satellite loops and radar out of Visakhapatnam, India show an impressive storm with plenty of heavy thunderstorms with cold cloud tops and a large 24-mile diameter eye. On Saturday morning (U.S. EDT time), the India Meteorological Department (IMD) was forecasting that Hudhud would have sustained winds of 170 - 180 kph (105 - 110 mph) at landfall, making it a strong Category 2 storm. JTWC was forecasting a stronger storm--Category 4 with 135 mph winds. IMD predicted a storm surge of 1 - 2 meters (3.3 - 6.6 feet) would occur near and to the right of where the center makes landfall. With warmer sea surface temperatures under the storm and wind shear in the 10 - 15 knot range, landfall as a Category 3 cyclone appears the most likely scenario when Hudhud hits the coast of northern Andhra Pradesh and southern Odisha between Visakhapatnam and Gopalpur on Sunday, October 12, near 06 UTC (2 am EDT.) Odisha was struck in 2013 by Category 4 Tropical Cyclone Phailin, which killed 45 people and did $700 million in damage. This death toll was extremely low, considering this is a region where 10,000 people died in a similar-strength cyclone in 1999.

Latest Hudhud warnings for India from the India Meteorological Department (IMD).
Latest Hudhud advisory from the India Meteorological Department (IMD).
Latest India radar.


Figure 3. Tropical Cyclone Hudhud as seen by radar out of Visakhapatnam, India at 16:20 UTC (12:20 pm EDT.)

Okinawa drenched and battered by Vongfong
Japan's Okinawa Island continues to take an epic battering from Typhoon Vongfong as the powerful storm steams slowly north-northwestwards at 10 mph. At 8 am EDT Saturday, Vonfong had weakened to a Category 1 storm with 85 mph winds, and at approximately 11 am EDT, the eye of the storm passed over northern Okinawa. Tropical storm-force winds of 39+ mph of greater began buffeting Okinawa at 5:39 am EDT Friday (6:39 pm local time), and continued through 7:54 am local time Saturday--a span of over 13 hours--with only 10 minutes of slight relaxation in the winds below tropical storm-force (to 36 - 38 mph.) During this period, Okinawa reached sustained winds of up to 64 mph, with gusts as high as 89 mph, and the pressure bottomed out at 950 mb at 11:15 pm local time. The Japan Meteorological Agency (JMA) AMeDAS site at Kunigami on the northern end of Okinawa reported 20.83" (529.0 mm) of rain in the past 48 hours. In second place was nearby Higashi, with 17.50" (444.5 mm) in the 48 hours. The capital of Okinawa, Naha, got 9.94" (252.5 mm) in 48 hours.


Figure 4. The northern portion of Vongfong's eyewall was all that remained of the storm's eyewall as the eye of the storm moved over the northern portion of Okinawa at 00:45 local time Sunday (11:45 am EDT.) Image credit: Japan Meteorological Agency.

Satellite loops and Japanese radar show that Vongfong's eyewall has collapsed, and the storm is rapidly weakening due to high wind shear and cooling waters. Tropical storm-force winds will continue to affect Okinawa intermittently through Sunday morning local time, but will not be as strong as what was experienced when the typhoon was approaching the island. Vongfong should continue to weaken and be a tropical storm with 50 - 60 mph winds when it makes landfall on the main Japanese island of Kyushu near 8 pm U.S. EDT time Sunday evening (00 UTC Monday.) Heavy rains from Vongfong will fall on soils already saturated by Typhoon Phanfone's rains last week, which could lead to much more severe flooding than was observed for Phanfone. Vongfong will also be moving slower than Phanfone was, potentially leading to higher rainfall amounts.

Storm Chaser James Reynolds is on Okinawa, and is posting updates and images to his Twitter feed.


Video 1. The cameras on the International Space Station captured this video of Super Typhoon Vongfong on October 9, 2014. The first 1.5 minutes is one of the most spectacular orbital pass videos of a tropical cyclone ever filmed. At the time, Vongfong was a Category 4 super typhoon with 155 mph winds.

Hurricane expert Steve Gregory has his take on the tropics in a Saturday afternoon post.

Jeff Masters

Hurricane

Subtropical Depression 7 Headed Towards Bermuda, but 90L is the One to Watch

By: JeffMasters, 3:38 PM GMT on October 10, 2014

Subtropical Depression Seven formed in the Atlantic at 11 am EDT Friday. The depression, located about 590 miles south of Bermuda, was headed northwest at 10 mph, and Bermuda is the only land area the storm poses a threat to. A tropical storm watch has been posted for the island, and the 11 am EDT Wind Probability Forecast from NHC gave Bermuda a 14% chance of seeing tropical storm-force winds of 39+ mph, with the strongest winds expected to affect the island Saturday evening into Sunday morning. Satellite loops showed STD 7 had very little heavy thunderstorm activity near its center, with most of the action in a curved band well to the north of the center. This is characteristic of a storm that is not fully tropical, thus the designation of the storm as a subtropical depression. Sea Surface Temperatures (SSTs) were warm, near 29°C (84°F), and wind shear was moderate, 5 - 15 knots. These conditions are favorable for slow development, and the depression is likely to get the name Fay Friday evening or Saturday morning. Disturbances getting their start from a cold-cored upper level low like STD 7 have plenty of cold, dry air aloft, which retards development into a tropical system. I expect STD 7 will be named Subtropical Storm Fay instead of Tropical Storm Fay, if it intensifies at expected. STD 7 will recurve to the northeast out to sea on Sunday without troubling any other land areas. An Air Force hurricane hunter aircraft has been tasked to investigate STD 7 on Friday afternoon.


Figure 1. Latest satellite image of Subtropical Depression Seven.

Pay attention to Invest 90L east of the Lesser Antilles
An area of disturbed weather associated with a tropical wave located about 700 hundred miles east of the northern Lesser Antilles Islands on Friday morning has been designated Invest 90L by the National Hurricane Center. This disturbance has the potential to be trouble, and needs to be watched carefully. Invest 90L was headed west to west-northwest at about 10 mph. Satellite loops showed 90L had a modest amount of spin and heavy thunderstorm activity, and these thunderstorms were poorly organized. Water vapor satellite loops show a good degree of dry air surrounding 90L, and this will retard development. Sea Surface Temperatures (SSTs) were warm, near 28.5°C (83°F), and wind shear was light, 5 - 10 knots. These conditions are favorable for development. The 8 am Friday run of the SHIPS model predicted that conditions would remain favorable for slow development through Monday, with light to moderate wind shear and SSTs near 29°C (84°F), though the atmosphere is expected to dry as the disturbance moves to the north of Puerto RIco early next week. All three of our reliable computer models for predicting tropical storm formation, the European, GFS, and UKMET models, showed 90L developing by the middle of next week in their 00Z Friday runs. When multiple models predict development, the odds of formation are increased. In their 8 am EDT Friday Tropical Weather Outlook, NHC gave 90L 2-day and 5-day development odds of 10% and 20%, respectively. Given the high model support for 90L's development, I put the 5-day odds of development higher, at 40%. 90L's west-northwest trajectory will carry it to a point about 100 - 200 miles north of Puerto Rico on Monday, and near the Southeast Bahamas and Turks and Caicos Islands on Wednesday.


Figure 2. Latest satellite image of Invest 90L near the Lesser Antilles.

Typhoon Vongfong giving Okinawa an epic battering
Japan's Okinawa Island is receiving an epic battering from Typhoon Vongfong as the powerful storm steams slowly northward at 9 mph. Cooler waters, higher wind shear, and an eyewall replacement cycle had weakened Vongfong to Category 4 strength with 135 mph winds as of 8 am EDT Friday, according to the Joint Typhoon Warning Center (JTWC), and the Japan Meteorological Agency (JMA) showed Vonfong's central pressure had risen to 925 mb at 9 am EDT Friday, up from a low of 900 mb on Wednesday. Satellite loops show that Vongfong is still an impressive storm with a very large area of heavy thunderstorms and a prominent 17-mile diameter eye.


Figure 3. High resolution imagery from the VIIRS instrument on the Suomi NPP satellite shows a highly detailed view of the eye of Super Typhoon Vongfong on October 9, 2014 at 03:55 UTC. At the time, Vongfong was a Category 4 storm with 155 mph winds. Image credit: NOAA Environmental Visualization Laboratory.

Okinawa at risk of a direct hit from Vongfong
Tropical storm-force winds of 39+ mph of greater have buffeted Okinawa since 5:39 am EDT Friday (6:39 pm local time), and this large and slow-moving typhoon will keep tropical storm-force winds blowing on the island for an extraordinary long period of time--over 48 straight hours, until approximately 10 am EDT (11 pm local time) Sunday. Wind gusts as high as 81 mph have already been measured on Okinawa, along with sustained winds as high as 59 mph. Our two top models for predicting tropical cyclone tracks, the GFS and European, both predicted with their 06Z and 00Z Friday runs, respectively, that the eye of Vongfong would pass over Okinawa near 15 UTC (11 am EDT) Saturday. With the typhoon moving over waters that will gradually cool, and with wind shear expected to rise from the moderate range (15 - 20 knots) to the high range (>20 knots), Vongfong should weaken and be a Category 2 or low-end Category 3 typhoon at that time. JMA is forecasting 500 - 700 mm (20 - 28 inches) of rain for Okinawa and nearby islands, and forecasts top sustained winds of 100 mph with gusts to 145 mph for the Okinawa region. Wave heights are forecast at 13 m (over 40 ft) for Okinawa and the Amami Islands to the north.

Rapid weakening should ensue as Vongfong approaches the main Japanese island of Kyushu this weekend, with Category 1 strength likely at landfall. In their 00Z Friday runs, the European and GFS models predicted landfall would occur on Kyushu between 8 pm - 11 pm U.S. EDT time Sunday evening (00 - 03 UTC Monday.) Heavy rains from Typhoon Vongfong are expected to fall on soils already saturated by Typhoon Phanfone's rains last week, which could lead to much more severe flooding than was observed for Phanfone. Vongfong will also be moving slower than Phanfone was, potentially leading to higher rainfall amounts.

Storm Chaser James Reynolds is on Okinawa, and is posting updates and images to his Twitter feed.
Latest Japanese radar shows heavy rain bands of Vongfong affecting Okinawa.


Figure 4. Tropical Cyclone Hudhud as seen by Astonaut Reid Wiseman from the International Space Station at 9:30 am EDT October 10, 2014. At the time, Hudhud was an intensifying Category 1 storm with 85 mph winds. Image credit: Reid Wiseman.

Dangerous Tropical Cyclone Hudhud a threat to India
Category 1 Tropical Cyclone Hudhud in the Bay of Bengal is steadily intensifying as it heads west-northwest towards India, with sustained winds estimated at 85 mph at 8 am EDT Friday. The storm is under moderately high wind shear of 20 knots, and is over warm waters of 30°C (86°F)--conditions which favor continued modest intensification. Satellite loops show a well-organized system with plenty of low-level spiral bands and an increasing amount of heavy thunderstorm activity. On Friday morning (U.S. EDT time), the India Meteorological Department (IMD) was forecasting that Hudhud would have sustained winds of 130 - 140 kph (81 - 87 mph) at landfall, making it a strong Category 1 storm. JTWC was forecasting a stronger storm--Category 3 with 115 mph winds. IMD predicted a storm surge of 1 - 2 meters (3.3 - 6.6 feet) would occur near and to the right of where the center makes landfall. With warmer sea surface temperatures ahead of the storm and wind shear expected to be in the 15 - 20 knot range, intensification into at least a Category 2 cyclone appears likely before Hudhud hits the coast of northern Andhra Pradesh and southern Odisha between Visakhapatnam and Gopalpur on Sunday, October 12, near 06 UTC. Odisha was struck in 2013 by Category 4 Tropical Cyclone Phailin, which killed 45 people and did $700 million in damage. This death toll was extremely low, considering this is a region where 10,000 people died in a similar-strength cyclone in 1999. IMD provided excellent early warning information for Phailin.

Latest Hudhud warnings for India from the India Meteorological Department (IMD)
Latest Hudhud advisory from the India Meteorological Department (IMD).
India radar from Machilipatnam.

Hurricane expert Steve Gregory has his take on the tropics in a Friday afternoon post.

Jeff Masters

Hurricane

Super Typhoon Vongfong Headed Towards Okinawa; 99L May Affect Bermuda

By: JeffMasters, 3:53 PM GMT on October 09, 2014

The winds are rising on Japan's Okinawa Island as Earth's most powerful tropical cyclone of 2014, Super Typhoon Vongfong, steams north-northwest at 8 mph. Vongfong peaked in intensity Tuesday with top sustained winds of 180 mph, and had weakened below Category 5 strength with 150 mph winds as of 11 am EDT Thursday, according to the Joint Typhoon Warning Center (JTWC.) The Japan Meteorological Agency showed Vonfong's central pressure rising to 915 mb at 9 am EDT Thursday, from a low of 900 mb on Wednesday. Satellite loops show that Vongfong is still an impressive storm with a large area of heavy thunderstorms and a prominent 30-mile diameter eye, but the cloud tops have warmed since Wednesday, and the area covered by the typhoon's heaviest thunderstorms has shrunk. Vongfong has two concentric eyewalls, and it is likely that the typhoon is undergoing an eyewall replacement cycle, where the inner eyewall will collapse and be replaced by the outer eyewall. This process should cause further weakening today.


Figure 1. Visible VIIRS image of Super Typhoon Vongfong in moonlight as seen at 2:44 pm EDT on October 8, 2014. At the time, Vongfong was a Category 5 storm with 165 mph winds. Image credit: Dan Lindsey, NOAA/NASA and RAMMB/CIRA.


Figure 2. Super Typhoon Vongfong as seen by Astonaut Reid Wiseman from the International Space Station at 7 am EDT October 9, 2014. Image credit: Reid Wiseman.

Okinawa at risk of a direct hit from Vongfong
Vongfong began a turn to the north on Wednesday morning, and is likely to pass over or just to the north of Japan's Okinawa Island near 18 UTC (2 pm EDT) Saturday. With the typhoon moving over waters that will gradually cool, and with wind shear expected to rise to the moderate range, weakening to Category 3 status is likely before Vongfong makes its closest pass by Okinawa. Rapid weakening should ensue as Vongfong approaches the main Japanese island of Kyushu this weekend, with Category 1 strength likely at landfall. In their 00Z Thursday runs, the European and GFS models predicted landfall would occur on Kyushu between 5 pm - 11 pm U.S. EDT time Sunday evening (21 UTC Sunday - 03 UTC Monday.) Heavy rains from Typhoon Vongfong are expected to fall on soils already saturated by Typhoon Phanfone's rains last week, which could lead to much more severe flooding than was observed for Phanfone. Vongfong will also be moving slower than Phanfone was, potentially leading to higher rainfall amounts.


Figure 3. MODIS satellite image of Tropical Storm Hudhud taken at approximately 2 am EDT October 9, 2014. At the time, Vongfong was intensifying and had 70 mph winds. Image credit: NASA.

Dangerous Tropical Cyclone Hudhud a threat to India
It's October, the usual time of year when the Southwest Monsoon over India begins to wane. As the monsoon retreats southwards away from India, its dominance over the atmosphere in the North Indian Ocean's Bay of Bengal weakens, allowing tropical cyclones to form after a four-month period of conditions hostile for tropical cyclone formation. The North Indian Ocean typically has two tropical cyclone seasons: one in May and early June before the arrival of the monsoon, and one in October - November as the monsoon retreats. There was one named storm this year during the first portion of the season: Tropical Storm Nanauk, which formed over the waters of the Arabian Sea on the west side of India on June 10, and dissipated on June 14 without hitting land. The second season is now at hand, as we have Tropical Cyclone Hudhud in the Bay of Bengal. Tropical Cyclone Hudhud was a strengthening tropical storm with 70 mph winds at 11 am EDT Thursday. The storm is under moderately high wind shear of 20 knots, and is over warm waters of 30°C (86°F)--conditions which favor some modest intensification. Satellite loops show a well-organized system with plenty of low-level spiral bands and an increasing amount of heavy thunderstorm activity. With warmer sea surface temperatures ahead of the storm and wind shear expected to be in the 15 - 20 knot range, intensification into at least a Category 2 cyclone appears likely before Hudhud hits the coast of northern Andhra Pradesh and southern Odisha between Visakhapatnam and Gopalpur on Sunday, October 12, between 00 - 06 UTC. Odisha was struck in 2013 by Category 4 Tropical Cyclone Phailin, which killed 45 people and did $700 million in damage. This death toll was extremely low, considering this is a region where 10,000 people died in a similar-strength cyclone in 1999. The India Meteorological Department (IMD) provided excellent early warning information for Phailin. On Thursday morning (U.S. EDT time), IMD was forecasting that Hudhud would have sustained winds of 130 - 140 kph (81 - 87 mph) at landfall, making it a strong Category 1 storm. JTWC was forecasting a stronger storm--Category 3 with 120 mph winds. IMD predicted a storm surge of 1 - 2 meters (3.3 - 6.6 feet) would occur near and to the right of where the center makes landfall.

Latest Hudhud warnings for India from the India Meteorological Department (IMD)
Latest Hudhud advisory from the India Meteorological Department (IMD).
India radar from Machilipatnam.


Figure 4. Latest satellite image of Invest 99L in the Western Caribbean.

Invest 99L in the Atlantic a possible threat to Bermuda
An area of disturbed weather associated with an upper-level cold-cored low pressure system, located a few hundred miles northeast of Puerto Rico on Thursday morning, was designated Invest 99L by the National Hurricane Center on Thursday morning. Invest 99L was headed northwest to north-northwest at about 10 mph. Satellite loops showed plenty of spin, since 99L was associated with a non-tropical low pressure system that had already established a vigorous circulation. 99L's heavy thunderstorms were poorly organized and limited to the east side of the center, due to strong upper-level winds from the west pushing dry air into the system. Sea Surface Temperatures (SSTs) were warm, near 29°C (84°F), and wind shear was moderate, 5 - 15 knots. Tthese conditions are favorable for development, but disturbances getting their start from a cold-cored upper level low like 99L have plenty of cold, dry air aloft, which retards development into a tropical system. The 8 am Thursday run of the SHIPS model predicted that conditions would remain favorable for slow development through Saturday, with moderate wind shear, a moist atmosphere, and SSTs near 29°C (84°F.) On Sunday, wind shear will rise above 25 knots and the atmosphere will dry, limiting the chances for development. One of our three reliable computer models for predicting tropical storm formation, the European, showed 99L developing in its 00Z Thursday run, and passing very close to Bermuda by Sunday evening. In their 8 am EDT Thursday Tropical Weather Outlook, NHC gave 99L 2-day and 5-day development odds of 30% and 40%, respectively. An Air Force hurricane hunter aircraft has been tasked to investigate 99L on Friday afternoon, if necessary.

At longer ranges, both the GFS and European models show development of Atlantic tropical depressions in 6 - 10 days, though they don't agree on where these storms might occur (the GFS develops something over the Bahamas, while the European model develops a tropical wave between the Lesser Antilles Islands and Africa.) While 6 - 10 day genesis forecasts are not to be trusted, the fact that both of these models are showing developing systems is an indication that the large-scale atmospheric conditions that have suppressed tropical storm formation during the 2014 Atlantic hurricane season may ease some next week, possibly due to the influence of the Madden Julian Oscillation (MJO), a pattern of increased thunderstorm activity near the Equator that moves around the globe in 30 - 60 days.

Wunderblogging hurricane expert Steve Gregory has more on the tropics in his Thursday afternoon post.

Jeff Masters

Hurricane

Super Typhoon Vongfong a Threat to Japan; Tropical Cyclone Hudhud Menaces India

By: JeffMasters, 2:21 PM GMT on October 08, 2014

Earth's most powerful tropical cyclone since 2013's devastating Super Typhoon Haiyan, Super Typhoon Vongfong, peaked in intensity Tuesday with top sustained winds of 180 mph, and has weakened slightly to peak winds of 165 mph as of 12 UTC Wednesday (8 am EDT), according to the Joint Typhoon Warning Center (JTWC.) Vonfong completed a very impressive bout of rapid intensification that took it from a Category 2 storm with 105 mph winds at 18 UTC Monday to Category 5 strength with 180 mph winds at 18 UTC Tuesday. These are the highest winds of any tropical cyclone JTWC has rated since Super Typhoon Haiyan's 195 mph winds of November 7, 2013 (JTWC's post-season analysis showed Haiyan weakened slightly to 190 mph winds at landfall in the Philippines.) The Japan Meteorological Agency has held Vonfong's central pressure at 900 mb between 18 UTC Tuesday and 12 UTC Wednesday--the lowest pressure of any typhoon they have rated since Super Typhoon Haiyan's 895 mb pressure of November 7, 2013.


Figure 1. Infrared VIIRS image of Super Typhoon Vongfong as seen at 17:03 UTC (1:03 pm EDT) on October 7, 2014. At the time, Vongfong was a peak-intensity Category 5 storm with 180 mph winds. Image credit: Dan Lindsey, NOAA/NASA and RAMMB/CIRA.


Figure 2. Infrared VIIRS images of some of the strongest Pacific tropical cyclones of the past year at their peak intensity. The colors tell us the temperature of the cloud tops. The colder the cloud tops, the higher they are, indicating stronger updrafts and thus a more vigorous tropical cyclone. The white colors are temperatures of -80°C (-112°F), and the pink colors (only seen in Haiyan) are still colder, about -85°C (-121°F). This is the temperature at the very top of the troposphere (base of the stratosphere), about 50,000 feet high. Haiyan (195 mph winds) stands out as being much more intense than the other super storms (Rammasun: 155 mph winds; Genevieve: 160 mph winds; Vongfong: 180 mph winds.) Image credit: Dan Lindsey, NOAA/NASA and RAMMB/CIRA (and thanks to TWC's Michael Lowry for putting this mosaic together.)

Vongfong is Earth's fourth Category 5 storm of 2014
Vongfong is Earth's fourth Category 5 storm of the year, and the second in the Western Pacific. The other Western Pacific Cat 5 was Super Typhoon Halong, which topped out at 160 mph winds on August 3, eventually making landfall in Japan on August 10 as a tropical storm. Another Western Pacific Super Typhoon, Rammasun, was only rated a Cat 4 when it hit China's Hainan Island on July 17, killing 195 people and causing over $7 billion in damage. However, a pressure characteristic of a Category 5 storm, 899.2 mb, was recorded at Qizhou Island just before Rammasun hit Hainan Island. If this pressure is verified, it is likely that the storm will be upgraded to a Category 5 in post-season reanalysis. The Eastern Pacific has had two Cat 5s in 2014 that did not affect land: Marie (160 mph winds) and Genevieve (160 mph winds.) The South Indian Ocean has had one Cat 5 this year, Tropical Cyclone Gillian in March (160 mph winds.) Gillian did not affect any land areas. Between 2000 - 2013, Earth averaged five Category 5 storms per year, with 51% of these occurring in the Western Pacific.

Vongfong a threat to Japan
Vongfong began a turn to the north on Wednesday morning, and is a threat to hit Japan on Sunday or Monday. Satellite loops show Vongfong is an extremely impressive storm, with a large area of heavy thunderstorms with very cold cloud tops, excellent upper-level outflow, and a large 25-mile diameter eye. With the typhoon over warm waters of 30°C (86°F) and under light wind shear of 5 - 10 knots, continued existence as a Category 5 storm is possible. The 11 am EDT Wednesday forecast from the Joint Typhoon Warning Center predicted that Vongfong would remain a Category 5 storm through 8 am Thursday. Cooler waters and higher wind shear will induce weakening by Friday as the typhoon approaches Japan. Vongfong will be recurving as it approaches Japan, and the models differ considerably on when and where this recurvature will take place, and thus when Vongfong will make landfall. In their 00Z Thursday runs, the European and GFS models both predicted landfall would occur on the main island of Kyushu, with the European model forecasting a landfall near 18 UTC Sunday, and the GFS model forecasting a landfall about twelve hours later, near 06 UTC Monday.


Figure 3. Rainfall from Typhoon Phanfone as estimated by NASA's TRMM satellite. The typhoon's heaviest rains stayed offshore, but some areas of 6+ inches (yellow colors) were observed west of Tokyo. The typhoon dumped 48 centimeters (19 inches) of rain in the mountainous region of Shizuoka Prefecture. At one point during the storm, rain fell in Shizuoka—the capital city of the prefecture—at a record-rate of 8.7 centimeters (3.4 inches) per hour. Heavy rains from Typhoon Vongfong are expected to fall on soils already saturated by Typhoon Phanfone's rains, which could lead to much more severe flooding than was observed for Phanfone. Image credit: NASA/TRMM


Figure 4. Typhoon Phanfone's heavy rains and resulting runoff led to sediment plumes in Japan's Suruga Bay, visible in the natural-color image (top) acquired October 6, 2014, by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite. Such plumes were not apparent on September 29 (bottom image). Image credit: NASA Earth Observatory.

Japan cleaning up from Typhoon Phanfone
Vongfong is following a track remarkably similar to Typhoon Phanfone, which made landfall as a Category 1 storm with 80 mph winds on Japan's main island of Honshu at 7:16 pm EDT Sunday, October 5, 2014 near the city of Hamamatsu in western Shizuoka Prefecture, about 125 miles west-southwest of Tokyo. A few hours later, the core of the typhoon passed over Tokyo, where sustained winds of 53 mph, gusting to 70 mph were recorded. Phanfone killed at least seven and left four missing, injuring at least 62 others. Heavy rains from Typhoon Vongfong are expected to fall on soils already saturated by Typhoon Phanfone's rains, which could lead to much more severe flooding than was observed for Phanfone. Vongfong will also be moving slower than Phanfone was, potentially leading to higher rainfall amounts.

RapidScat measures Tropical Storm Simon's winds
An ocean wind measurement instrument called ISS-RapidScat was launched on September 20, 2014 on a SpaceX Dragon cargo spacecraft, which docked with the International Space Station (ISS) a few days later. On September 30, RapidScat was plucked out of the Dragon and installed on the Space Station, with full activation occurring the next day. Remarkably, we already have the first test data from the instrument--a swath of ocean surface wind data taken in Tropical Storm Simon off the coast of Mexico's Baja Peninsula on October 4. The RapidScat data showed the size of Simon's wind field very well, and would have been of value for NHC to help define the radius of gale (34 kts) and storm-force (50 kts) winds surrounding the storm. It will take a month or more of calibration and testing before RapidScat's winds are ready for real-time forecasting, but this sample data from Simon shows that we have a great new tool to help out with hurricane and marine wind forecasting! See my blog post on RapidScat from September 30 and NASA's October 6 article for more details on this promising new instrument.


Figure 5. Tropical Storm Simon's winds as seen by the International Space Station-RapidScat scatterometer as the storm approached Mexico's Baja California Peninsula at 0210 UTC Time Oct 4 (7:10 p.m. PDT Oct 3). At the time, Simon was intensifying and had top winds of 50 mph. RapidScat gives erroneously high winds in precipitation, and the higher winds (red colors) in this image are not as strong as indicated. Image Credit: NASA-JPL/Caltech.


Video 1. Time-lapse footage of the RapidScat "wind watcher" instrument being installed on the International Space Station, followed by reaction by the team after its activation.

Dangerous Tropical Cyclone Hudhud a threat to India
It's October, the usual time of year when the Southwest Monsoon over India begins to wane. As the monsoon retreats southwards away from India, its dominance over the atmosphere in the North Indian Ocean's Bay of Bengal weakens, allowing tropical cyclones to form after a four-month period of conditions hostile for tropical cyclone formation. The North Indian Ocean typically has two tropical cyclone seasons: one in May before the arrival of the monsoon, and one in October - November as the monsoon retreats. This second season is now at hand, as we have Tropical Cyclone Hudhud in the Bay of Bengal. Tropical Cyclone Hudhud was a strengthening tropical storm with 50 mph winds at 11 am EDT Wednesday, and the storm is under moderate wind shear of 10 - 15 knots and is over warm waters of 29°C (84°F)--conditions which favor intensification. Satellite loops show a well-organized system with plenty of low-level spiral bands and an increasing amount of heavy thunderstorm activity. With warmer sea surface temperatures ahead of the storm and wind shear expected to remain light to moderate, intensification into at least a Category 3 cyclone appears likely before Hudhud hits the central east coast of India on Sunday between 00 - 12 UTC.

Quiet in the Atlantic
Our top three models for predicting tropical cyclone genesis show nothing developing over the next five days in the Atlantic, though we should watch an area of disturbed weather between the Bahamas and Bermuda that could develop early next week. If development does occur, Bermuda would likely be the only land area affected by the storm.

Heavy rains in Central America
A low pressure area over Central America will move off the Pacific coast of Nicaragua late this week and potentially spawn a tropical depression in the Eastern Pacific this weekend. The UKMET and GFS models do develop this system, while the European model does not. In their 8 am EDT Wednesday Tropical Weather Outlook, NHC gave this Pacific disturbance 5-day development odds of 30%. This disturbance is a threat to bring heavy rains and dangerous flooding to Central America over the next five days.

Jeff Masters

Hurricane

Super Typhoon Vongfong Winds Hit 180 mph: Earth's Strongest Storm Since Haiyan

By: JeffMasters, 8:46 PM GMT on October 07, 2014

Earth's most powerful tropical cyclone since 2013's devastating Super Typhoon Haiyan is Super Typhoon Vongfong. Vongfang is in the midst of a very impressive bought of rapid intensification that took it from a Category 2 storm with 105 mph winds at 18 UTC Monday to Category 5 strength with 180 mph winds at 18 UTC Tuesday, according to the Joint Typhoon Warning Center (JTWC.) These are the highest winds of any tropical cyclone they have rated since Super Typhoon Haiyan's 195 mph winds of November 7, 2013 (JTWC's post-season analysis showed Haiyan weakened slightly to 190 mph winds at landfall in the Philippines.) The 18:45 UTC October 7 advisory for Vongfong from the Japan Meteorological Agency put the storm's central pressure at 900 mb--the lowest of any typhoon they have rated since Super Typhoon Haiyan's 895 mb pressure of November 7, 2013.


Figure 1. Super Typhoon Vongfong as seen in moonlight at 17:03 UTC (1:03 pm EDT) on October 7, 2014. At the time, Vongfong was a Category 5 storm with 180 mph winds. Image credit: Dan Lindsey, NOAA/NASA and RAMMB/CIRA.

Vongfong is Earth's fourth Category 5 storm of 2014
Vongfong is Earth's fourth Category 5 storm of the year, and the second in the Western Pacific. The other Western Pacific Cat 5 was Super Typhoon Halong, which topped out at 160 mph winds on August 3, eventually making landfall in Japan on August 10 as a tropical storm. Another Western Pacific Super Typhoon, Rammasun, was only rated a Cat 4 when it hit China's Hainan Island on July 17, killing 195 people and causing over $7 billion in damage. However, a pressure characteristic of a Category 5 storm, 899.2 mb, was recorded at Qizhou Island just before Rammasun hit Hainan Island. If this pressure is verified, it is likely that the storm will be upgraded to a Category 5 in post-season reanalysis. The Eastern Pacific has had two Cat 5s in 2014 that did not affect land: Marie (160 mph winds) and Genevieve (160 mph winds.) The South Indian Ocean has had one Cat 5 this year, Tropical Cyclone Gillian in March (160 mph winds.) Gillian did not affect any land areas. Between 2000 - 2013, Earth averaged five Category 5 storms per year, with 51% of these occurring in the Western Pacific.

Vongfong a threat to Japan
Vongfong passed through the U.S. Mariana islands of Guam, Rota, Saipan, and Tinian on Sunday as a Category 2 storm with 105 mph winds, causing mostly minor damage. The typhoon is expected to turn to the north by Thursday, and is a threat to hit Japan next Monday. Satellite loops show Vongfong is an extremely impressive storm, with a large area of heavy thunderstorms with very cold cloud tops, excellent upper-level outflow, and a large 30-mile diameter eye. With the typhoon over warm waters of 30°C (86°F) and under light wind shear of 5 - 10 knots, continued intensification is possible. The 5 pm EDT Tuesday forecast from the Joint Typhoon Warning Center predicted that Vongfong would top out with sustained 190 mph winds at 2 pm EDT on Wednesday. Cooler waters and higher wind shear will induce weakening later in the week as the typhoon approaches Japan.

Jeff Masters

Hurricane

Super Typhoon Vongfong Headed Towards Japan

By: JeffMasters, 3:07 PM GMT on October 07, 2014

Category 4 Super Typhoon Vongfong is at the verge of Category 5 strength with 155 mph winds as it continues a period of rapid intensification in the waters about 1000 miles south of Japan. Vongfong plowed through the U.S. Mariana islands of Guam, Rota, Saipan, and Tinian on Sunday as a Category 2 storm with 105 mph winds, causing mostly minor damage. The typhoon is expected to turn to the north on Wednesday, and is a threat to hit Japan on Monday. Satellite loops show Vongfong is an extremely impressive storm, with a large area of heavy thunderstorms with very cold cloud tops, excellent upper-level outflow, and a large 30-mile diameter eye. With the typhoon over warm waters of 30°C (86°F) and under light wind shear of 5 - 10 knots, intensification into a Category 5 storm by Wednesday appears likely. Cooler waters and higher wind shear will induce weakening late in the week as the typhoon approaches Japan. Vongfong is the third Super Typhoon of 2014 in the Western Pacific. The others were Halong (160 mph winds, the only Cat 5 so far), Rammasun (155 mph winds), and Neoguri (155 mph winds.) A Super Typhoon is defined as being any Western Pacific typhoon with sustained winds of 150 mph or greater.


Figure 1. MODIS satellite image of Typhoon Vongfong taken at approximately 10 pm EDT October 6, 2014. At the time, Vongfong was intensifying from a Category 3 storm with 115 mph winds to a Category 4 storm with 140 mph winds. Image credit: NASA.

Japan cleaning up from Typhoon Phanfone
Vongfong is following a track remarkably similar to Typhoon Phanfone, which made landfall as a Category 1 storm with 80 mph winds on Japan's main island of Honshu at 7:16 pm EDT Sunday, October 5, 2014 near the city of Hamamatsu in western Shizuoka Prefecture, about 125 miles west-southwest of Tokyo. A few hours later, the core of the typhoon passed over Tokyo, where sustained winds of 53 mph, gusting to 70 mph were recorded. Phanfone killed at least seven and left four missing, injuring at least 62 others.


Figure 2. High waves batter a breakwater at a port at Kihou town in Mie prefecture, central Japan on October 6, 2014, from Category 1 Typhoon Phanfone. Image credit: JIJI PRESS/AFP/Getty Images.

Simon's remnants to bring heavy rains to Arizona
In the Eastern Pacific, Tropical Storm Simon has weakened to sustained winds of 40 mph at 11 am EDT Tuesday, and will likely dissipate by Tuesday night. Simon's remnants will slosh to the northeast over the north-central coast of Mexico's Baja Peninsula and into Mainland Mexico, bringing 3 - 6" of rain into these regions though Wednesday. Deep moisture from Simon will flow northeastward into the Southwest U.S., bringing a round of heavy rains for Arizona. There will not be as much moisture associated with Simon compared to the what the remnants of Hurricane Odile brought in September; rainfall amounts of 1 - 2" can be expected over Arizona Tuesday - Friday from Simon's remnants.


Figure 3. Predicted precipitation for the three-day period 8 am EDT Tuesday - 8 am EDT Friday from the NWS Weather Prediction Center. A plume of 1 - 2" of rain is predicted over Northern Mexico and Arizona from the remnants of Hurricane Simon.

Quiet in the Atlantic
Our top three models for predicting tropical cyclone genesis show nothing developing over the next five days in the Atlantic, though the 06Z Tuesday run of the GFS model shows an area of disturbed weather between the Bahamas and Bermuda could develop early next week. We should also keep an eye on the Southwest Caribbean off the coast of Nicaragua late this week. Low pressure over Central America will be capable of forming a center of circulation over the Caribbean, as the GFS model has been suggesting with recent runs. Anything that develops in the Caribbean should move slowly to the northwest early next week, bringing very heavy rains to much of Central America. What is more likely to happen is that the low pressure area over Central America will spawn a strong tropical disturbance by Sunday in the Pacific off the coast of Guatemala, as predicted by the UKMET and European models. In their 8 am EDT Tropical Weather Outlook, NHC gave this Pacific disturbance 5-day development odds of 20%.

Jeff Masters

Hurricane

Typhoon Phanfone Hits Japan; Typhoon Vongfong Next?

By: JeffMasters, 3:30 PM GMT on October 06, 2014

Typhoon Phanfone made landfall as a Category 1 storm with 80 mph winds on Japan's main island of Honshu at 7:16 pm EDT Sunday, October 5, 2014 near the city of Hamamatsu in western Shizuoka Prefecture, about 125 miles west-southwest of Tokyo, according to the Japan Meteorological Agency. A few hours later, the core of the typhoon passed over Tokyo, where sustained winds of 53 mph, gusting to 70 mph were recorded. More than 2 million people across Japan were advised to evacuate as Phanfone came ashore. In Okinawa, Japan, three U.S. servicemen were swept away by Phanfone's 12 - 15 foot waves; the body of one was recovered, but the other two remain missing. Heavy rain from Phanfone triggered at least two mudslides in Japan. Two men went missing after mudslides in Yokohama, in Kanagawa Prefecture. A 21-year-old surfer and college student is also missing after going surfing in waters just south of Tokyo off the coast of Kanagawa Prefecture. Phanfone brought heavy rains to Japan, with 19.17" (487 mm) falling at Mount Amagi, Shizuoka Prefecture, 10.06" in Tokyo and 12.72" in Yokohama. A peak gust of 101.8 mph was recorded at Omaezaki, Shizuoka Prefecture, at 8:07 a.m. Monday, and a sustained wind of 72 mph was observed at Irozaki on the southern tip of the Izu Peninsula, Shizuoka Prefecture, at 9:01 a.m. Monday.


Figure 1. Typhoon Phanfone approaching Japan, as seen by the MODIS instrument on NASA's Aqua satellite at 04:55 UTC October 5, 2014. At the time, Phanfone was a Category 2 storm with 105 mph winds. Image credit: NASA.

Typhoon Vongfong hits the Mariana Islands
Category 2 Typhoon Vongfong plowed through the U.S. Mariana islands of Guam, Rota, Saipan, and Tinian on Sunday as a Category 2 storm with 105 mph winds. The eye passed just north of the island of Rota, about 25 miles north of Guam. According to the Guam Pacific Daily News, about 70% of Rota lost power, but there were no injuries and only minor damage--buildings on the island are built mostly of concrete, limiting the amount of damage a typhoon can do. Winds at Andersen AFB on the north end of Guam reached 44 mph with a peak gust of 60 mph, but were undoubtedly higher on Rota. Vongfong dumped 7.69" of rain on Guam. The typhoon is expected to turn more to the northwest later in the week, and could be a threat to Japan in 6 - 7 days. Satellite loops show Vongfong is moderately well-organized, with plenty of low-level spirals bands, good upper-level outflow, but no eye visible. With the typhoon over warm waters of 30°C (86°F) and under moderate wind shear of 10 - 20 knots, intensification into a Category 4 storm by Wednesday appears likely, before cooler waters and higher wind shear induce weakening late in the week as the typhoon approaches Japan.


Figure 2. MODIS satellite image of Typhoon Vongfong taken at approximately 9 pm EDT October 5, 2014. At the time, Vongfong was a Category 1 storm with 90 mph winds, and had just passed through the Mariana Islands, passing just north or Rota. Image credit: NASA.

Simon weakening rapidly
In the Eastern Pacific, Tropical Storm Simon has weakened to sustained winds of 45 mph at 11 am EDT Monday, after topping out as a Category 4 hurricane with 135 mph winds at 11 pm EDT Saturday. Simon was the eighth intense hurricane so far in the Eastern Pacific (east of 140°W), putting this year in a tie with 1992 for the highest number of major hurricanes in one season. Simon will likely dissipate by Tuesday, and its remnants will slosh to the northeast over the central coast of Mexico's Baja Peninsula and into Mainland Mexico, bringing 3 - 6" of rain into these regions though Wednesday. Deep moisture from Simon will flow northeastward into the Southwest U.S. this week, bringing a round of heavy rains for Arizona and New Mexico. There will not be as much moisture associated with Simon compared to the what the remnants of Hurricane Odile brought in September; rainfall amounts of 1 - 2" can be expected over Arizona and New Mexico Tuesday - Thursday from Simon's remnants.


Figure 3. Predicted precipitation for the three-day period 8 am EDT Monday - 8 am EDT Thursday from the NWS Weather Prediction Center. A plume of 1 - 2" of rain is predicted over Northern Mexico and the Southwest U.S. from the remnants of Hurricane Simon.

Quiet in the Atlantic
Our top three models for predicting tropical cyclone genesis show nothing developing over the next five days in the Atlantic. However, the models predicts that an area of low pressure will develop over Central America near Nicaragua late this week, with the European model putting the focus of the low over Nicaragua's Pacific waters, while the GFS model prefers a location in the Southwest Caribbean. NHC is leaning towards the solution offered by the European model, and in their 8 am EDT Tropical Weather Outlook, give a 5-day probability of 20% for a tropical depression to form off the Pacific coast of Nicaragua this week. We should not discount the GFS model's prediction, though, and keep an eye on the Southwest Caribbean this week. Anything that develops should move slowly to the northwest, bringing very heavy rains to much of Central America late this week.

Hurricane expert Steve Gregory offers his latest take on the tropics and the large-scale weather pattern over North America in his Sunday afternoon post.

Jeff Masters

Hurricane

Typhoon Phanfone Aims at Tokyo; Typhoon Vongfong Belting Guam

By: JeffMasters, 1:38 PM GMT on October 05, 2014

Typhoon Phanfone is weakening as is races northeastward towards the main Japanese island of Kyushu. Japanese radar showed that heavy rains from Phanfone were affecting most of the main Japanese islands of Kyushu and Honshu on Sunday morning, and satellite loops showed that Phanfone remained intact in the face of wind shear in excess of 30 knots, with a large area of heavy thunderstorms and a prominent eye. Phanfone will make its closest pass by Tokyo near 01 UTC Monday (9 pm EDT Sunday.) High wind shear and cooler waters will continue to weaken Phanfone, and it should be no stronger than a Category 1 storm at its point of closest approach to Tokyo. Heavy rains from Phanfone are the main threat, and are likely to bring dangerous flash flooding and mudslides.

According to TWC's Nick Wiltgen, Tokyo has a pretty high threshold for record rainfall. In data going back to 1886, the top ten one-hour rainfalls are all at least 69.2 mm (2.72 inches), and the calendar-day rainfall record rainfall since 1875 is 371.9 mm (14.64 inches). The top sustained wind on record since 1875 is 31.0 m/s or 69.3 mph, and a mere 22.6 m/s (50.6 mph) wind from Phanfone would give Tokyo an all-time top-10 sustained wind. The highest wind gust on record for central Tokyo is 46.7 m/s (104.5 mph) which, like the sustained wind record, was set September 1, 1938.


Figure 1. Radar image of Typhoon Phanfone taken at 22:15 JST (9:15 am EDT) Sunday, October 5, 2014 from the Japan Meteorological Agency.

Typhoon warnings in Guam for Category 2 Vongfong
Typhoon warnings are flying for the U.S. Northern Mariana islands of Guam, Rota, Saipan, and Tinian as intensifying Category 2 Typhoon Vongfong plows west-northwest at 24 mph through the islands. The island of Rota, about 25 miles north of Guam, is expected to receive the worst beating. The eye of Vongfong is on track to pass just to the north of Rota, as seen on radar out of Guam. The NWS is warning that Rota could see sustained winds of 90 - 110 mph, which will cause extensive damage. A storm surge of 3 - 5 feet and rains of 5 - 8 inches are also expected. As of 9 am EDT Sunday (11 pm local time), winds had begun to rise sharply at Andersen AFB on the north end of Guam, with a peak gust of 33 mph. The typhoon is expected to turn more to the northwest later in the week, and could be a threat to Japan in 6 - 8 days.


Figure 2. Radar out of Guam of Typhoon Vongfong, taken at 9:29 am EDT Sunday. The radar cannot "see" all of Rota due to blockage of the radar beam by mountains.

Simon says: I'm a major hurricane!
In the Eastern Pacific, Hurricane Simon put on an impressive burst of rapid intensification Saturday, topping out as a Category 4 hurricane with 135 mph winds at 11 pm EDT Saturday. Simon is the eighth intense hurricane so far in the Eastern Pacific (east of 140°W), putting this year in a tie with 1992 for the highest number of of major hurricanes in one season. The 2014 Eastern Pacific hurricane season tally now stands at 18 named storms, 13 hurricanes, and 8 intense hurricanes. An average Eastern Pacific hurricane season sees just 15 named storms, 8 hurricanes, and 3 intense hurricanes during the entire year, with two of those named storms and one hurricane occurring after October 10. Simon is expected to recurve to the northeast, and bring rains of 2 - 4" to the central coast of Mexico's Baja Peninsula as it dissipates near landfall on Tuesday. Deep moisture from Simon will flow northeastward across Mainland Mexico and into the Southwest U.S. this week, and the 00Z Sunday runs of the GFS and European models are in agreement that heavy rainfall from Simon's moisture will begin to affect the Southwest U.S. on Wednesday.


Figure 3. MODIS satellite image of Hurricane Simon taken at approximately 6 pm EDT October 4, 2014. At the time, Simon was a Category 3 storm with 120 mph winds and was undergoing rapid intensification that would take it to a Category 4 storm with 135 mph winds by 11 pm EDT. Image credit: NASA.

Quiet in the Atlantic
Our top three models for predicting tropical cyclone genesis show nothing developing over the next five days in the Atlantic, though the GFS model predicts the waters in the Southwest Caribbean off the coast of Costa Rica could spawn a large area of low pressure capable of developing into a tropical depression next weekend.

Jeff Masters

Hurricane

Category 3 Typhoon Phanfone Pounding Japan

By: JeffMasters, 7:02 PM GMT on October 04, 2014

Dangerous Category 3 Typhoon Phanfone is pounding the small islands south of the main Japanese island of Kyushu with torrential rains and wind gusts of up to 101 mph as the storm heads north towards Tokyo. Winds at Japan's Kita-daitō (North Daitō Island) gusted to 45.3 m/s (101 mph) at 2:35pm JST (1:35 am U.S. EDT) on Saturday, before the wind observations were knocked offline. Minami-daitō has set an all-time calendar-day record for the month of October with 217.0 mm (8.54 inches) of rain, beating the old October record of 198.5 mm on Oct. 26, 2010. Daily rainfall records go back to 1942 there (thanks go to TWC's Nick Wilgen for these stats.) Japanese radar showed that rains from the outer spiral bands of Phanfone were moving over southern Kyushu and southeastern Honshu on Saturday afternoon (in U.S. EDT time.) Satellite loops show that Phanfone remains a large typhoon with a prominent eye, but wind shear of 30 knots is disrupting the storm and stretching it into an oval shape, with the heavy thunderstorms no longer as intense. Our two top models for predicting typhoon tracks, the GFS and European, predicted with their 12Z Saturday runs that Phanfone would hit the main Japanese island of Honshu near 18 UTC on Sunday, and make its closest pass by Tokyo near 00 UTC Monday (8 pm EDT Sunday.) High wind shear and cooler waters will continue to weaken Phanfone, and it should be no stronger than a Category 1 storm at its point of closest approach to Tokyo. Heavy rains from Phanfone are the main threat, and are likely to bring dangerous flash flooding and mudslides. The 12Z Saturday morning run of the GFDL model predicted that Phanfone would dump widespread rains of 4 - 8" across much of Japan.


Figure 1. Radar image of Typhoon Phanfone taken at 03:35 JST (2:35 pm EDT Saturday, October 4, 2014) from the Japan Meteorological Agency.


Figure 2. Predicted precipitation for Typhoon Phanfone as simulated by the GFDL model at 12Z Saturday October 4, 2014. Phanfone was predicted to dump rains of 8+ inches (yellow colors) across portions of Japan. Image credit: NOAA/GFDL.

A Typhoon Watch in Guam for Typhoon Vongfong
Typhoon Vongfong was headed west-northwest at 14 mph in the Pacific waters about 550 miles east-southeast of Guam at 11 am EDT Saturday, and that island is under a Typhoon Watch. Vongfong is expected to pass though the Northern Mariana Islands on Monday as a Category 2 or 3 typhoon. The storm is expected to turn more to the northwest later in the week, and could be a threat to Japan in 7 - 9 days.


Figure 3. Latest satellite image of Hurricane Simon.

Simon says: I'm a hurricane!
In the Eastern Pacific, Hurricane Simon put on a burst of rapid intensification Saturday morning to became the season's thirteenth hurricane. A NOAA hurricane hunter aircraft was investigating the storm Saturday afternoon, and at 1:20 pm EDT found a central pressure of 952 mb and flight level winds at 10,000 feet of 130 mph, which typically translates to a surface wind speed of 115 mph--which would make Simon a low-end Category 3 hurricane. Simon is expected to recurve to the north, and dissipate off the central coast of Mexico's Baja Peninsula on Tuesday. The 12Z Saturday runs of the GFS and European models have come into agreement that Simon's remnants will bring another round of heavy rainfall to the Southwest U.S. beginning on Wednesday.

Simon's ascension to hurricane status gives the unusually busy 2014 Eastern Pacific hurricane season 18 named storms, 13 hurricanes, and 7 intense hurricanes so far (east of 140°W.) An average Eastern Pacific hurricane season sees just 15 named storms, 8 hurricanes, and 3 intense hurricanes during the entire year, with two of those named storms and one hurricane occurring after October 10. If Simon becomes an intense hurricane, as appears likely, 2014 will tie with 1992 for the highest number of intense Eastern Pacific hurricanes in one season--eight. Simon is the 12th consecutive named storm to become a hurricane in the Eastern Pacific, after Genevieve, Hernan, Iselle, Julio, Karina, Lowell, Marie, Norbert, Odile, Polo, and Rachel. The previous record for consecutive hurricanes in the Eastern Pacific was eight, set in 1992 (Orlene, Iniki, Paine, Roslyn, Seymore, Tina, Virgil, Winifred.) Thanks go to wunderground members CybrTeddy and Mark Cole for looking up these stats.

Quiet in the Atlantic
Our top three models for predicting tropical cyclone genesis show nothing developing over the next five days.

Hurricane expert Steve Gregory offers his take on what rest of hurricane season might bring in his Thursday afternoon post.

Jeff Masters

Hurricane

Typhoon Phanfong a Heavy Rainfall Threat for Japan

By: JeffMasters, 3:39 PM GMT on October 03, 2014

Dangerous Category 3 Typhoon Phanfone is steaming northwest at 11 mph towards Japan, and is likely to bring that nation serious flooding problems over the weekend. Satellite loops show that Phanfone is a large and well-organized typhoon with a prominent eye and a large area of intense thunderstorms. However, conditions for intensification are no longer as favorable, with wind shear now a high 20 knots on Friday morning. Ocean temperatures remained warm, though, near 30°C (86°F). Ocean temperatures will cool sharply and wind shear will rise further on Saturday as the typhoon approaches Japan, weakening the storm. Our two top models for predicting typhoon tracks, the GFS and European, predicted with their 00Z Friday runs that Phanfone would hit the main Japanese island of Honshu near 18 UTC on Sunday. The Joint Typhoon Warming Center continues to maintain a forecast keeping the core of the storm offshore of Japan, as they believe Phanfone will be unable to penetrate very far westward into the strong upper-level westerly headwinds that will be present over Japan this weekend. Phanfone will be steadily weakening as it approaches Japan, and should be no stronger than a Category 1 storm at its point of closest approach. Heavy rains from Phanfone will arrive in Japan on Saturday, and are likely to bring dangerous flash flooding and mudslides. The Friday morning 06Z run of the GFDL model predicted that Phanfone would dump widespread rains of 8+ inches across much of Japan. One area of particular concern is the Mt. Ontake volcano, which erupted last Saturday, killing 47 and leaving dozens missing. Phanfone's heavy rains will mobilize Mt. Ontake's ash deposits into dangerous mudflows, seriously complicating the search for victims of Japan's deadliest volcanic eruption in 90 years.


Figure 1. MODIS satellite image from NASA's Aqua satellite of Typhoon Phanfone taken at 01:55 UTC October 3, 2014. At the time, Phanfone was a Category 3 storm with 125 mph winds, and had a 35-mile diameter eye, after completing an eyewall replacement cycle. Compare this to the 5-mile diameter eye seen the previous day (Figure 2, below.) Image credit: NASA.


Figure 2. The pinhole 5-mile diameter eye of Typhoon Phanfone as seen by the VIIRS instrument on the Suomi satellite on October 2, 2014. Image credit: Dan Lindsey, NOAA.


Figure 3. Predicted precipitation for Typhoon Phanfone as simulated by the GFDL model at 06Z Friday October 3, 2014. Phanfone was predicted to dump widespread rains of 8+ inches (yellow colors) across much of Japan. Image credit: NOAA/GFDL.

Next up for Japan: Tropical Storm Vongfong?
The Western Pacific's newest tropical storm, Tropical Storm Vongfong, formed Thursday evening in the Pacific waters about 1800 miles east of the Philippines. The storm is headed west-northwest at 11 mph, and is expected to intensify into a major typhoon by early next week. This storm may also be a threat to Japan 8 - 10 days from now.

Tropical Storm Simon a potential threat to Mexico's Baja Peninsula
In the Eastern Pacific, Tropical Storm Simon, with sustained winds of 60 mph at 11 am EDT Friday, was headed west-northwest at 9 mph away from the coast. Simon is expected to recurve to the north early next week, and could be a heavy rainfall threat to Mexico's Baja Peninsula on Tuesday and Wednesday. However, the models are in substantial disagreement on the long-range fate of Simon. The usually reliable European model keeps the storm well to the west away from Mexico's Baja Peninsula through Friday of next week, while most of the rest of the reliable models (GFS, UKMET, GFDL, and HWRF) show landfall in the Central Baja Peninsula on Tuesday or Wednesday. NHC is currently splitting the difference between these two extremes, since it is unclear which model solution will be correct. If the GFS model is correct, Simon could bring another round of heavy rainfall to the Southwest U.S. late next week.

Quiet in the Atlantic
Our top three models for predicting tropical cyclone genesis show nothing developing in the Atlantic over the next five days. A major outbreak of dry air from the Sahara, unusual for this time of year, is currently in progress over the Tropical Atlantic, which will make it difficult for anything to form between Africa and the Lesser Antilles Islands over the coming week.

Hurricane expert Steve Gregory offers his take on what rest of hurricane season might bring in his Thursday afternoon post.

Jeff Masters

Hurricane

Category 3 Typhoon Phanfone Headed Towards Japan; Tropical Storm Simon Forms in EPac

By: JeffMasters, 3:28 PM GMT on October 02, 2014

Typhoon Phanfone took advantage of light wind shear of 5 - 10 knots and very warm ocean temperatures of 30°C (86°F) to intensify into a dangerous Category 4 typhoon early Thursday morning. The typhoon's inner eyewall began collapsing later on Thursday morning as Phanfone entered an eyewall replacement cycle, reducing its intensity to a Category 3 storm with 125 mph winds. Once this cycle completes, Phanfone will have the opportunity to re-strengthen, as ocean temperatures will remain near 30°C (86°F) through Friday with light wind shear. Ocean temperatures will cool sharply and wind shear will rise on Saturday as the typhoon approaches Japan, weakening the storm. The models have come into better agreement on the track of Phanfone, but it remains uncertain if the typhoon will hit the main Japanese island of Honshu as the GFS, GFDL, and European models are calling for, or pass just offshore.


Figure 1. MODIS satellite image from NASA's Aqua satellite of Typhoon Phanfone taken at 04:20 UTC October 2, 2014. At the time, Phanfone was a Category 4 storm with 135 mph winds. Image credit: NASA.


Figure 2. Predicted precipitation for Typhoon Phanfone as simulated by the GFDL model at 06Z Thursday October 2, 2014. Phanfone was predicted to dump widespread rains of 8+ inches (yellow colors) across much of Japan. One area of particular concern is the Mt. Ontake volcano, which erupted on Saturday. Image credit: NOAA/GFDL.

Heavy rains from Phanfone will arrive in Japan on Saturday, and are likely to bring dangerous flash flooding and mudslides. The Thursday morning 06Z run of the GFDL model predicted that Phanfone would dump widespread rains of 8+ inches across much of Japan. One area of particular concern is the Mt. Ontake volcano, which erupted last Saturday, killing 47 and leaving dozens missing. Phanfone's heavy rains will mobilize Mt. Ontake's ash deposits into dangerous mudflows, seriously complicating the search for victims of Japan's deadliest volcanic eruption in 90 years.

Tropical Storm Simon forms in the Eastern Pacific
In the Eastern Pacific, Tropical Storm Simon formed Thursday morning a few hundred miles south of the Pacific coast of Mexico. Simon was headed west-northwest near 10 mph way from the coast, but is expected to bring 3 - 5 inches of rain to the southwest coast of Mexico. Simon is expected to recurve to the north early next week, and could be a heavy rainfall threat to Mexico's Baja Peninsula on Tuesday and Wednesday. Simon's formation gives the unusually busy 2014 Eastern Pacific hurricane season 18 named storms, 12 hurricanes, and 7 intense hurricanes so far. An average Eastern Pacific hurricane season sees just 15 named storms, 8 hurricanes, and 3 intense hurricanes during the entire year, with two of those named storms and one hurricane occurring after October 10. If Simon becomes a hurricane, as predicted by NHC, it will become the 12th consecutive named storm to become a hurricane in the Eastern Pacific, after Genevieve, Hernan, Iselle, Julio, Karina, Lowell, Marie, Norbert, Odile, Polo, and Rachel. The previous record for consecutive hurricanes in the Eastern Pacific was eight, set in 1992 (Orlene, Iniki, Paine, Roslyn, Seymore, Tina, Virgil, Winifred.) Thanks go to wunderground members CybrTeddy and Mark Cole for looking up these stats.


Figure 3. Dust from the Sahara can be seen streaming westwards across the tropical Atlantic in this October 1, 2014 composite image from the VIIRS instrument on the Suomi spacecraft. Two disturbances in the waters south of Canada, 97L and 98L, are also marked. Image credit: NOAA Visualization Lab.

Quiet in the Atlantic
A tropical wave predicted to come off the coast of Africa on Saturday is no longer being given support for development by our top three models for predicting tropical cyclone genesis. A major outbreak of dry air from the Sahara, unusual for this time of year, is currently in progress over the Tropical Atlantic, which will make it difficult for anything to form between Africa to the Lesser Antilles Islands over the coming week. Two disturbances in the waters south of Canada that were being given 10% chances of development on Wednesday by NHC, 97L and 98L, have decreased in organization since Wednesday, and are no longer being given a chance to develop.

Jeff Masters

Hurricane

Quietest Atlantic Hurricane Season Since 1986

By: JeffMasters, 3:59 PM GMT on October 01, 2014

The traditional busiest month of the Atlantic hurricane season, September, is now over, and we are on the home stretch. Just three weeks remain of the peak danger portion of the season. September 2014 ended up with just two named storms forming--Dolly and Edouard. Since the active hurricane period we are in began in 1995, only one season has seen fewer named storms form in September--1997, with Category 3 Hurricane Erika being the only September storm. Between 1995 - 2014, an average of 4.3 named storms formed in September. With only five named storms so far in 2014, this is the quietest Atlantic hurricane season since 1986, when we also had just five named storms by the beginning of October. In terms of Accumulated Cyclone Energy (ACE), activity in the Atlantic up until October 1 has been only about 43% of the 1981 - 2010 average.


Figure 1. Tracks of Atlantic named storms in 2014. Note how all of this year's hurricanes (tracks in red) have occurred well north of the tropics, north of 24°N latitude--a testament to how hostile for development conditions have been in the tropics, due to dry, sinking air. Image credit: National Hurricane Center.

Forecast for the remainder of hurricane season
Looking at climatology, since 1995, we have seen an average of 3.6 named storms form in the Atlantic after October 1. Two of those years--2006 and 2002--saw no storms form after October 1. The most post-October 1 storms was eleven, which occurred in 2005--no surprise there! The latest 2-week forecast from the GFS and European models show a continuation of the basic atmospheric pattern we've seen over the tropical Atlantic this season, with plenty of dry, sinking air. These conditions should lead to lower than average activity into mid-October, which is when historically, Atlantic hurricane activity begins to drop sharply. I expect we'll see at least one more named storm in the Atlantic this year, with two a more likely number. It's unlikely we'll get three or more post-October 1 named storms.

During October, the focus of Atlantic tropical cyclone genesis shifts to the Western Caribbean, Gulf of Mexico, and the waters between the Bahamas and Bermuda. The Lesser Antilles typically see very few tropical cyclones after October 1, and I expect their hurricane season is over. Sea Surface Temperatures over the Caribbean are currently 0.2°C above average, and 0.4°C above average in the Gulf of Mexico.


Figure 2. Atlantic hurricane activity begins to fall off sharply around mid-October.


Figure 3. Vertical instability over the Caribbean in 2014. The instability is plotted in °C, as a difference in temperature from near the surface to the upper atmosphere. Thunderstorms grow much more readily when vertical instability is high. Normal instability is the black line, and this year's instability levels are in blue. The atmosphere has been dominated by high pressure and dry, sinking air since June, which has made it difficult for tropical storms to develop, and no tropical depressions or tropical storms have been able to form in the Caribbean this year. Image credit: NOAA/CIRA.

Quiet in the Atlantic
A tropical wave predicted to come off the coast of Africa on Saturday is forecast by the UKMET and GFS models to develop by Monday in the vicinity of the Cape Verde Islands. An upper-level trough of low pressure over the Eastern Atlantic will bring high wind shear to this region early next week, though, making developing difficult. Another major invasion of dry air from the Sahara is currently in progress over the Tropical Atlantic, which will make it difficult for any tropical storms to make the crossing from Africa to the Lesser Antilles intact.


Figure 4. Dust from the Sahara can be seen streaming eastwards across the tropical Atlantic in this September 30, 2014 composite image from the VIIRS instrument on the Suomi spacecraft. Image credit: NOAA Visualization Lab.

Eastern Pacific tropical disturbance 90E a heavy rainfall threat
In the Eastern Pacific, an elongated area of disturbed weather (Invest 90E) was located a few hundred miles south of the Pacific coast of Mexico on Wednesday morning, and was headed west-northwest near 10 mph. This disturbance has good support from all three of our top tropical cyclone genesis models to develop this week. In their 8 am EDT Wednesday Tropical Weather Outlook, NHC gave 90E 2-day and 5-day odds of development of 70% and 90%, respectively. 90E is a threat to bring heavy rains to the Pacific coast of Mexico throughout the week. So far, though, 90E's heavy rains have remained offshore, as seen on satellite loops. Tropical Depression Rachel dissipated a few hundred miles west of Baja, Mexico on Tuesday.

Typhoon Phanfone a threat to Japan
In the Western Pacific, Tropical Storm Phanfone has taken advantage of light wind shear of 5 - 10 knots and extremely warm ocean temperatures of 31°C (88°F) and intensified into a Category 1 typhoon. Ocean temperatures will cool slightly to 30°C (86°F) on Thursday but wind shear will remain light, which should allow Phanfone to intensify into a Category 4 typhoon, and possibly a super typhoon with winds of 150 mph or greater. The typhoon is headed northwest towards Japan, and the 00Z Wednesday runs of the GFS and European models both show Phanfone recurving to the northeast and making landfall on the southern Japan main island of Kyushu early next week. However, the models are widely divergent in their handling of the trough of low pressure expected to pull Phanfone to the northeast, resulting in major differences in the forward speed of the storm. The GFS model has landfall occurring near 18 UTC on Sunday, while the European model is almost two days slower, with a 12 UTC Tuesday landfall. Given these huge differences in the forecasts from our top two typhoon track models, the long-range fate of Phanfone is highly uncertain.

Jeff Masters

Hurricane


The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

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Cat 6 lead authors: WU cofounder Dr. Jeff Masters (right), who flew w/NOAA Hurricane Hunters 1986-1990, & WU meteorologist Bob Henson, @bhensonweather