Category 6™

Winter's Back!

By: JeffMasters, 8:50 PM GMT on December 30, 2014

WEATHERINTEL SERVICES
30-DEC-14 (Next Update FRIDAY – JAN 2)

By Steve Gregory for vacationing Jeff Masters


ARCTIC AIR OVERSPREADING MUCH OF THE NATION

Arctic air is surging southward from the Rockies eastward, sending Temps below normal for the first time in over a month. Well below normal Temps are expected to dominate much of the nation east of the Rockies for the next 2 weeks – with significant storm systems impacting the eastern half of the nation every 6-8 days. The only exception will be over Florida where Temperatures are still expected to remain on the warm side of normal.

A large scale long wave TROF now dominates the nation, with the center of the Polar Vortex over Hudson Bay, while a High pressure ridge continues to build over the eastern most Pacific into Alaska. This upper air pattern will provide a colder flow from the arctic southward into the central US this week, and into the easternmost states by next week. Although this is a far more seasonable pattern, all global models continue to show a highly progressive flow which will cause significant oscillations in Temperature anomalies during the next 2 weeks, with anomalies varying from 'just' a few degrees below normal to 20 degrees below normal.

A small but potent short wave TROF is now plunging southward over Nevada and will trigger a Low pressure system over the SW Deserts by tomorrow, with snow possible from near Las Vegas into the higher elevations of Arizona. This system will then move into Texas by the end of the week where it will intensify and then head for the Great Lakes region over the weekend. For over a week now, the models have been extremely consistent on the projected track for this storm, with the storm center tracking from the eastern Great Lakes/Ohio Valley thru the interior of New England. This should result in mostly rain in the Boston-Washington DC coastal corridor, while heavy snows fall inland.

The global model runs have been fairly consistent in their upper air pattern forecasts, but there continues to be a significant difference between the models for time periods beyond 8 days. In general, the GFS has been the ‘coldest’ of the models, as both the longer range ’New’ GFS (which goes operational mid-month) and the European models show stronger systems heading eastward from the Pacific which then force a breakdown in the Ridge near the West coast – ultimately bringing a milder flow aloft into the central US and stronger storm formations east of the Rockies.

As the models continue to struggle with the El Niño like flow pattern that continues to exert itself over the Pacific basin upper air pattern, a number of forecast tools show the EPAC ridge breaking down by mid Jan. For this reason, there is a reasonable chance of seeing Temps return to near and eventually above normal levels during the second half of JAN.



CLICK IMAGE to open full size image in new window

Fig 1: The various global model forecasts valid on the evening of JAN 09 ... There are fairly significant differences in model projections at 10 Days out with the operational GFS showing a relatively weak short wave in the northern Rockies, while the ‘New’ GFS and EURO models show a much more potent system in the west. (Qualitatively, the ‘New’ GFS appears to have a lot in common with the ECMWF for forecasts beyond 1 week...)




Fig 2: The GFS Ensemble forecasts for 5 Teleconnection indices. Curiously, the AO, NAO and PNA do NOT support long term cold in the eastern half of the nation (A positive AO and NAO imply above normal Temps over the eastern US – while a Negative PNA implies mild weather for the southeastern US). However, 2 other, lessor known teleconnections (the WPO and EPO) do support cold weather in the east. Nonetheless, having such inconsistencies between teleconnections implies higher than normal uncertainty for forecasts beyond 8-12 days out.




Fig 3: The MJO has become better organized and somewhat stronger over the last few days as it moves slowly eastward over Indonesia and the Philippines. Forecasts (especially those from the GFS ensemble run) call for the enhanced phase of the MJO to propagate eastward and strengthen some over the next 2 weeks. IF correct, this will place it in the western Pacific in 2 weeks – and supports a warmer pattern over the US during the 2nd half of JAN..




Fig 4: The Temperature anomaly forecast is based STRICTLY on the GFS MOS model data output which calls for below normal Temperatures nationwide – with the exception of Florida. Anomalies will vary considerably every few days due to the approaching storm system this weekend.




Fig 5: The Week 2 Temperature ANOMALY forecast is based on the 12Z run of the HI-RES operational GFS (80%) integrated with the 00Z EURO model (5%), the 12Z GFS ensemble mean (5%) and the ‘NEW’ GFS (10%) - using the projected pattern, along with the GFS surface and 850mb Temperature forecasts. Some Temp forecasts are adjusted for known or expected anomalous thermal patterns and/or projected storm systems. Though well below normal Temps will dominate the eastern half of the nation (except for Florida…) the fairly progressive pattern, especially in the southern stream, introduces greater uncertainty for Week 2 Temperature anomalies. However, based on much better consistency from run-to-run for the last week, Confidence in the general Temp anomaly pattern and its absolute values, is near average for this far out in time, with a rating of ‘3’ on a Scale of ‘1-5’ for both metrics.

✭ The next Weather Update will be issued FRIDAY – JAN 2

Steve

NOTES:

1. A GENERAL Glossary of Weather Terms can be found HERE

2. Another Glossary of weather terms is available HERE

2 Week Temperature Forecast Winter Weather

Much Colder Temps Ahead

By: JeffMasters, 9:39 PM GMT on December 28, 2014

WEATHERINTEL SERVICES
28-DEC-14 (Next Update TUESDAY – DEC 30)

By Steve Gregory for vacationing Jeff Masters


COLD AIR SPREADING SLOWLY WEST TO EAST

It took long enough, but above normal Temps still lingering in the East will be history by late this week, with very cold conditions likely during Week 2. A fairly impressive storm system will be bringing rain and snow to the central and eastern US by next weekend. At this time, the storm is expected to track from the western Gulf coast region to the Great Lakes – implying rain for much of the coastal Plain in the east, and snow likely from the Plains to the upper Midwest.

A large scale long wave TROF continues to develop over North America, with the center of the Polar Vortex likely to take up residence near Hudson Bay this week along with increased ridging in the EPAC on into Alaska. This will establish a progressively colder flow from the arctic southward into the northern Rockies and central US later this week and will continue across the nation during Week 2 as well.

While the latest global model runs have ‘stabilized’ somewhat in their projections beyond 8 days, there is again a growing disconnect between the global models – with today’s GFS now the ‘coldest’ of the models, as both the longer range ’New’ GFS (which goes operational mid-month) and the latest European model show a more zonal-like flow developing again in 10-14 days. The models continue to struggle with the El Niño like flow pattern that continues to exert itself over the Pacific where basin wide SST anomalies are forcing a highly zonal flow do dominate the central Pacific. With a number of forecast tools showing the EPAC ridge breaking down in 10-14 days as a developing blocking upper level High moves from over Alaska to the Arctic Ocean – we have a reasonable chance of seeing Temps return to near and eventually above normal during the second half of JAN. (Though the models show warming to begin just before mid JAN - with the very cold arctic air in place by Week 2, it will take some time for the arctic air to be displaced - despite the milder, zonal flow aloft that is expected to develop in about 10-14 days.




Fig 1: The Latest GFS forecast compared to the European ECMWF 10 Days out. The GFS shows a very strong vortex centered in eastern Canada with a strong, secondary Vorticity Lobe/TROF westward into the Canadian Rockies. Although a westerly flow off the Pacific is shown impinging on the west coast – overall heights are near normal, and later time steps show the major TROF re-amplifying into the US. OTH, the European and the NEW GFS (not shown) shows a weaker primary vortex in Canada, rising heights in the central and western IS, and a more progressive flow of strong disturbances over the Pacific. This implies a moderating Temp trend in 10-14 days. For the moment, I’ve opted to go with the colder GFS for Week 2.




Fig 2: The GFS Ensemble forecast for the 3 major Teleconnection indices shows a plunge into a negative AO and NAO phase occurring right now, but interestingly, are shown going positive in 7-14 days (though there is high uncertainty for the AO as demonstrated by the large spread in solutions for the individual Ensemble members during Week 2). The negative trending PNA is shown returning to near neutral during Week 2 as well. (A Negative AO and NAO imply below normal Temps over the eastern half of the nation – while Positive values imply warmer than normal. A Positive PNA implies cold weather for the eastern US). In sum – these forecasts argue for near (or even above) normal Temps again developing after mid month.




Fig 3: The above Temperature forecasts are based STRICTLY on the GFS MOS model data output which calls for above normal Temps over the eastern US on AVERAGE during the next 7 days, but anomalies will fall below normal by the end of the week - along with stormier weather next weekend.




Fig 4: The Week 2 Temperature ANOMALY forecast is based on the 12Z run of the HI-RES operational GFS (85%) integrated with the 00Z EURO model (5%) & 12Z GFS ensemble mean (10%) - using the projected pattern, along with the GFS surface and 850mb Temperature forecasts. Some Temp forecasts are adjusted for known or expected anomalous thermal patterns and/or projected storm systems. (The ‘NEW’ GFS was NOT used for today’s forecast.) Though much below normal Temps will dominate the nation, there is still significant uncertainty in the daily Temp forecasts after Day 10. This is due to large variations in the models’ upper air projections – and an equally large uncertainty on where and how much additional snow cover there will be by next week. However, based on much better consistency from run-to-run for the last 5 days, Confidence in the general Temp anomaly pattern and its absolute values, is near average, with a rating of ‘3’ on a Scale of ‘1-5’ for both metrics.


✭ The next Weather Update will be issued TUESDAY – DEC 30

Steve

NOTES:

1. A GENERAL Glossary of Weather Terms can be found HERE

2. Another Glossary of weather terms is available HERE

2 Week Temperature Forecast Winter Weather

Top 10 Weather Videos of 2014

By: JeffMasters, 3:48 PM GMT on December 26, 2014

The year 2014 had many spectacular extreme weather events caught on video; the most remarkable were of flash flooding in Serbia and a tornado in Russia. Two artistic videos that were favorites of mine included beautiful time-lapse pieces set to music taken of monsoon thunderstorms in Arizona and the sunset/aurora on top of Mt. Washington, New Hampshire. Here, then, are my choices for 2014's top 10 weather videos:


#1. A Russian man pulls out of his garage just as a tornado arrives. He tries to go back in the garage, but it is destroyed before he can. Note: The dash cam date is incorrect; the tornado occurred on August 29, 2014 in Bashkiria, Russia. According to http://www.extremestorms.com.au/tornado-bashkiria-russia/, the tornado was an EF-3 that killed two people and injured 80.

#2. Nicolaus Wegner's Stormscapes 2 video is the most impressive collection of time-lapse severe storm footage I've ever seen. His 7-minute time-lapse compilation of his May - September 2014 adventures in Wyoming, Montana, South Dakota, Nebraska, and Colorado feature an impressive rainbow at 0:40, an incredible orange cumulonimbus at 4:00, a sequence of spectacular funnel clouds and tornadoes beginning at 5:10, and some stunning mammatus clouds at 6:04. Highly recommended.


#3. Torrential rains in Serbia in September 2014 caused flash floods that killed one person and swept way cars.


#4. 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.


#5. Futuristic and creative 3-D weather graphics like you've never seen before light up the screen in this forecast for September 23, 2050 video released by the Weather Channel. The video was made in response to an appeal by the World Meteorological Organization (WMO) to television weather presenters world-wide to imagine a “weather report from the year 2050,” based on the best science we have as summarized in the 2014 Intergovernmental Panel on Climate Change (IPCC) report. If humanity’s current "business as usual" approach to emissions of heat-trapping gases like carbon dioxide continues, the average temperature of the Earth’s lower atmosphere could rise more than 4°C (7.2°F) by the end of the 21st century. But what does a global average temperature rise really mean? How would we experience it on a daily basis? The video imagines a future when it wouldn't take a landfalling hurricane to push water levels two feet above normal in Miami Beach--the onshore winds of a hurricane passing 400 miles offshore could cause that level of flooding, due to sea level rise. The report also envisions that the current 15-year drought affecting the Southwest U.S. will continue into 2050, becoming a decades-long "megadrought". On the lighter side, we hear about a new baseball team called the "Alberta Clippers" (named after a type of fast-moving snowstorm that originates in Alberta), and see Jim Cantore calling up hurricane tracking charts on his outstretched hand.


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

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#7. Official trailer for the 2014 Hollywood tornado disasters movie, "Into the Storm". The most impressive special effects are shown here, so save yourself the painful melodrama of the movie and just watch the trailer. My review of this disaster of a movie is here.


#8. A Low-Precipitation (LP) supercell thunderstorm on May 18, 2014, between Wright and Newcastle, WY. The best footage begins about 0:50 into the clip. The rotation of the thunderstorm is beautifully captured. LP supercells usually form in dry regions, where there might be just enough moisture to form the storm, but not enough moisture to rain very hard. You can usually find the updraft on the rear flank (back) of the storm. On radar, an LP will not show up as a hook echo because there's not enough precipitation within the storm to provide the reflectivity. These storms might not look that strong, but they can pack a punch. LP supercells often produce tornadoes and large hail.


#9. An EF-2 tornado with 120 mph winds hit this camp for oil workers just south of Watford City, North Dakota, on May 27, 2014. The tornado injured nine people and damaged or destroyed 15 trailers. Dan Yorgason, who lives in a neighboring workers camp to the one destroyed, filmed the tornado from inside his truck. "The tornado was coming down the hill along our only escape route. There was nowhere for us to go. It was crazy," he said. The contrast of the brown of the lower part of the funnel with the white portion of the upper funnel is particularly striking 2:00 into the video.


#10. Rare twin tornadoes near Pilger and Wisner, Nebraska as caught by iowachase.com (AKA ‪‪StormChasingVideo‬‬.com.)

Steve Gregory will be covering my blog for me from Sunday December 28 until January 2. Have a Happy New Year, everyone!

Jeff Masters

Climate Summaries Extreme Weather

Top Ten Weather Stories of 2014

By: JeffMasters, 5:36 PM GMT on December 23, 2014

#1: Earth Likely Had Its Warmest Year on Record
The year 2014 has made it very apparent that global warming has not stopped, as the year-to-date-period January - November 2014 was Earth's warmest such period since record keeping began in 1880, according to NOAA's National Climatic Data Center (NCDC). If December is at least 0.42°C (0.76°F) higher than its 20th century average, 2014 will surpass 2005 and 2010 as the warmest year on record; the departure of temperature from average during the first three weeks of December has exceeded that mark, making it likely that 2014 will end up as the warmest year on record in NOAA's reckoning. The average global sea surface temperature was the highest for January - November in the 135-year period of record, due in large part to seven consecutive months (May - November) of record warmth. Remarkably, the record-warm global temperatures of 2014 occurred in the absence of El Niño, a large-scale warming of the eastern and central equatorial Pacific Ocean that historically has been present whenever an extended period of record-warm global temperatures have occurred.


Figure 1. Departure of temperature from average for January - November 2014, the warmest such period for the globe since record keeping began in 1880. Portions of every continent with good data were record warm, particularly for Europe. Image credit: National Climatic Data Center (NCDC) .

#2: Monsoon Floods in the India-Pakistan Border Region Kill 648
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, according to insurance broker Aon Benfield. 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 in this summer's deluge, 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.


Figure 2. 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)

#3: India's Cyclone Hudhud Does $11 Billion in Damage
Tropical Cyclone Hudhud powered ashore near Visakhapatnam in the Andhra Pradesh state of India on October 12 as a Category 4 storm with sustained winds of 135 mph. With damage estimated at $11 billion, Hudhud was by far the most expensive tropical cyclone in India's history, and their third most expensive weather-related natural disaster, according to EM-DAT, the International Disaster Database. However, Hudhud also represents a success story--due to aggressive efforts to evacuate vulnerable areas, the death toll from Hudhud was held to 68, far below the 9,843 people killed during the similar-strength October 28, 1999 Orissa Cyclone which hit India's coast very close to where Hudhud hit.


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.

#4: Southeastern Brazil's Worst Drought in 50 Years
Southeastern Brazil's worst drought in 50 years has brought São Paulo, South America's largest city with a population near 20 million, to the brink of running out of water. The drought has cost at least $4.3 billion, making it the third most expensive natural disaster in Brazil's history. This is the second consecutive year of disastrous drought in Brazil--drought in Northeast Brazil during the first five months of 2013 caused an estimated $8 billion in damage, making it Brazil's second most expensive natural disaster in history. According to the international disaster database EM-DAT, Brazil's costliest natural disaster was the drought of 1978 ($2.3 billion in 1978 dollars, or $8.3 billion 2014 dollars.)


Figure 4. Cattle in a drought-parched field in Quixada, Ceara state, Brazil on January 2, 2014. Small farmers in Ceara state have not able to harvest corn to feed cattle, and have been selling them at a loss. Image credit: Aurelien Francisco Barros/AFP/Getty Images.

#5: The California Drought
Severe, extreme or exceptional drought covered 95% of California by September 2014, thanks to a drought that one research team said was the state's worst 1-year and 3-year drought for at least 1,200 years. The California Farm Water Coalition estimated agricultural losses at $3.6 billion.


Figure 5. One of the key water supply reservoirs for Central California, Lake Oroville, on January 20, 2014. Image credit: California Department of Water Resources.

#6: Deadly Landslide in Afghanistan Kills up to 2,700
The deadliest weather disaster of 2014 may have been the tragic landslide in the Argo District of Badakhshan Province, NE Afghanistan on May 2. Death toll estimates vary widely, from 350 - 2,700. According to Dave's Landslide Blog, the landslide came after prolonged heavy rainfall in the region and occurred in the middle of the day on a Friday, when many people are likely to be at home. The slide occurred in two phases, with an initial slide that buried many people. In the aftermath, many people from local villages went to help, only to be buried by the second landslide.


Figure 6. Aftermath of the deadly landslide in the Argo District of Badakhshan Province, NE Afghanistan, on May 2, 2014. Image credit: BBC correspondent Bilal Sarwary.

#7: Super Typhoon Rammasun Kills 206 in China
With a name meaning “thunder of God,” Rammasun was the strongest typhoon to hit China’s Hainan Province in 41 years. Rammasun peaked as a Category 4 super typhoon with 155 mph, and hit China with top sustained winds of 140 mph. Rammasun killed 206 and did $6.5 billion in damage, according to insurance broker Aon Benfield.


Figure 7. Super Typhoon Rammasun as seen by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite at 1:35 p.m. local time (0535 UTC) on July 18, 2014. The storm had a well-defined eye situated just off the coast of northern Hainan Island, and a pressure of 899.2 mb was measured at a small island in the eye. Image credit: NASA Natural Hazards.

#8: "Polar Vortex" Cold Hits Eastern U.S.
The same unusually sharp kink in the jet stream that brought record drought to California in January also brought extreme cold and snow to the eastern two-thirds of the United States, with a deep trough of low pressure ushering in the notorious "Polar Vortex" cold air outbreak. Ice cover on the Great Lakes reached its second highest extent on record during the winter, and two crippling snow and ice storms hit the deep South, shutting down Atlanta for multiple days. Total damages during the January 5 - 8 portion of this winter's cold blast were $3 billion and 21 people died, according to insurance broker Aon Benfield.


Figure 8. Abandoned cars litter Cobb Parkway (US 41) in Atlanta, Georgia between Cumberland Pkwy and W. Paces Ferry Road. Image credit: Michael King @mhking

#9: A Hyperactive 2014 Eastern Pacific Hurricane Season
In 2014 the Eastern Pacific (east of 140°W) saw 20 named storms, 13 hurricanes, and 8 intense hurricanes, making it the busiest season since 1992, which set records for total number of named storms (24), hurricanes (14), and intense hurricanes (8). An average Eastern Pacific hurricane season sees 15 named storms, 8 hurricanes, and 3 intense hurricanes. 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

Unusually warm ocean temperatures allowed an unprecedented three hurricanes to pass within 200 miles of Hawaii in 2014, including Hurricane Iselle, which made landfall on the Big Island on August 8, 2014 as a tropical storm with 60 mph winds--only the second recorded landfall of a tropical storm on the Big Island.


Figure 9. 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 was being intercepted by the high mountains of Hawaii, and could not "see" to the northwest.

#10: A Quiet Atlantic Hurricane Season
The 2014 Atlantic hurricane season ended up with well below average activity--8 named storms, 6 hurricanes, 2 intense hurricanes, and an Accumulated Cyclone Energy (ACE) that was 63% of the 1981 - 2010 median. The 1981 - 2010 average was 12 named storms, 6 hurricanes, and 3 major hurricanes. The death and damage statistics for the 2014 Atlantic hurricane season were gratifyingly low: there were only five deaths (four from Hurricane Gonzalo in the Lesser Antilles and one from Tropical Storm Dolly in Mexico), and total damages from all storms were less than $500 million. The quiet season was due to an atmospheric circulation that favored dry, sinking air over the tropical Atlantic, and high wind shear over the Caribbean. Sea Surface Temperatures were also near-average, and considerably cooler than what we've gotten used to since the active hurricane period that began in 1995.


Figure 10. Hurricane Gonzalo as seen from the International Space Station on October 16, 2014. At the time, Gonzalo was at peak strength, with 145 mph winds, and was the first Atlantic hurricane to reach sustained winds of at least 145 mph since Hurricane Igor of 2010. Gonzalo hit Bermuda just a week after Hurricane Fay hit the island, and Gonzalo's remnants went on to batter the United Kingdom on October 21 with wind gusts exceeding 100 mph, killing three people there. Image credit: Alexander Gerst.

Happy Holidays, everyone, and I'll be back Friday with a new post.

Jeff Masters

Climate Summaries Extreme Weather

NO WHITE CHRISTMAS FOR EASTERN U.S.

By: JeffMasters, 8:23 PM GMT on December 21, 2014

WEATHERINTEL SERVICES
By Steve Gregory substituting for Jeff Masters
21-DEC-14 (Next Update TUESDAY – DEC 23 on my own Blog)


PATTERN CHANGE TO BRING NORMAL TEMPS XMAS

Above normal Temps continue to persist across much of the nation, but will begin trending back to normal later this week, with below normal Temps likely to develop from west to east after starting next weekend and continuing into the New Year. .

A large scale long wave TROF will be forming over North America as the week progresses, with a strong vorticity Max forcing the development of a large area of locally heavy precip in the southeastern US by late Monday, with a storm system expected to form along the Gulf coast. This storm will move northward into the eastern Great Lakes by XMAS, with a warm flow along the east coast (including New England) and locally heavy rains. While some snow may fall on the back side of the storm across the western Great Lakes and upper Ohio Valley – total amounts are not expected to be heavy.

Although a cold flow will become established following this storm, it will take some time for deep arctic air to develop over Canada, so Temps will be close to normal going next weekend, before falling below normal during the week just prior to New Years. The latest global model runs continue to show large run-to-run forecast variations on just how long and how cold it will be during the first 10 days of JAN – as the atmosphere has taken on an El Niño like flow, with some indications that a southern branch of the flow from the Pacific will be undercutting the main TROF over North America during the first half of JAN, limiting the extent, and at times the intensity, of the arctic air surge into the U.S.

Further out, due to the large swings in model projections in the longer ranges, exactly what the pattern will be in JAN is nothing more than a toss-up at this point. That said, with the continuing oscillation of the major teleconnection forecasts (AO, NAO, and PNA) every 2-3 weeks, a small uptick again in Equatorial SST’s in the Niño regions, the continuing positive North Pacific decadal SST pattern, and uncertainty on the strength of the next MJO signal now evolving over the Indian Ocean - a forecast for a ‘highly variable’ (El Niño like) pattern, with large swings in Temp anomalies during JAN seems to be the most likely outcome at this time; along with several more significant rain events in drought stricken California Ca. (More information on the impact of MJO, El Niño and the Pacific decadal oscillation can be found on numerous postings on my own Blog over the past month and the last Winter Outlook posted here and on my Blog.)



CLICK BOTTOM IMAGE to open full size image in new window

Fig 1: The various global model forecasts valid on the evening of DEC 30... There are very large differences in model projections at 10 Days out with equally large variations in the projected Temps – especially during Week 2. The GFS is actually the coldest, while the ‘New’ GFS (which goes online in mid JAN) is the ‘mildest’ of last nights' runs. OTH, the European and Canadian models imply stormier weather during Week 2, with the European model warmer than the GFS but colder than the Canadian. The latest GFS run (not shown) is similar to last nights 00Z run, and has been largely accepted when developing the Temp anomaly forecasts. Nonetheless, the result is a high uncertainty for Temp anomalies during the first week in JAN – though the odds favor solidly below normal Temps across the nation.




Fig 2: The above chart shows High Temps reported yesterday across North America. Note that sub-zero readings are confined to the high arctic in northern Canada and the interior of Alaska (where DEC Temps have averaged 5°-15° above normal so far). Though the upper level flow favors much colder air moving into the US later this week, it will take 4-67 days for deeper, arctic air to develop over Canada first, before plunging into the U.S.




Fig 3: The GFS Ensemble forecasts for the NAO, AO and PNA Teleconnections out thru 14 days. There is an extremely large divergence in the forecasts for the AO and NAO during the last 6 days of the forecast period, with very large implications for Temp anomalies during the first half of JAN. (A Negative AO and NAO imply below normal Temps over the eastern half of the nation – while Positive values imply warmer than normal.)




Fig 4: The SSt anomalies across the Pacific show a continuation of well above normal values from the northern most Pacific/Gulf of Alaska to the eastern Pacific, with a currently weak El Niño event in progress, and a wedge of cold water from off the coast of Japan eastward across much of the North Pacific. The atmosphere has responded to this SST anomaly pattern during the last 3+ weeks with an El Niño like flow (which I expected when developing my Winter Outlook). This type of flow brought the unusually long lasting mild pattern this month along with the heavy rain events to California. This SST anomaly pattern is no doubt contributing to the large divergences in model solutions for periods beyond 7-10 days exhibited by all global models for over a week now.




Fig 5: The SST and Wind anomalies over the Equatorial Pacific continue to show an El Niño event in progress. After Temps fell off a bit around the start of DEC due to the upwelling phase of a passing Kelvin wave – they have begun to warm again as the down-welling phase of a Kelvin wave and weaker than normal Trades have again developed in the EPAC. It appears the Niño 3.4 region will see SST anomalies approach +1.0° by the start of JAN – regardless of how the next MJO cycle evolves. (Whether the SST’s remain above normal in FEB, however, is at least partially related to the next MJO cycle.)




Fig 6: The above Temperature forecasts are based STRICTLY on the GFS MOS model data sets which call for above normal Temps nationwide on average during the week ahead, but anomalies have decreased considerably from the past 2 weeks and will fall to near zero or slightly below normal by next Sunday.




Fig 7: The Week 2 Temperature ANOMALY forecast is based on the 12Z run of the HI-RES operational GFS (90%) integrated with the 00Z EURO model (5%), & 12Z GFS ensemble mean (5%) - using the projected pattern, along with the GFS surface and 850mb Temperature forecasts. Some Temp forecasts are adjusted for known or expected anomalous thermal patterns and/or projected storm systems. Though solidly below normal Temps will dominate much of the nation, there is still significant uncertainty in the daily Temp forecasts after Day 10. This is due to large variations in the models’ upper air projections – and an equally large uncertainty on where and how much additional snow cover there will be by the opening days of JAN. Therefore, Confidence in the general Temp anomaly pattern and its absolute values, is below average, with a rating of ‘2’ on a Scale of ‘1-5’.

✭ The next Weather Update will be issued TUESDAY – DEC 23 on my own Blog

Steve

Winter Weather 2 Week Temperature Forecast

Hurricane Science Legend Dr. Robert Simpson Dies at Age 102

By: JeffMasters, 11:29 PM GMT on December 19, 2014

Dr. Robert Simpson, one of the originators of the familiar Saffir-Simpson scale, passed away peacefully in his sleep today at the age of 102. Dr. Simpson began his meteorology career in 1940. During the early 1950s, he urged the U.S. Weather Bureau management to fund modest levels of hurricane research, but budgets didn't allow this. However, the devastating 1954 Atlantic hurricane season changed the minds of several New England congressmen. A special appropriation was passed to improve the Weather Bureau's hurricane warning system, and Bob Simpson was appointed to head up the National Hurricane Research Project in 1955. He held that post until 1959, when he left the Project to finish his doctorate in meteorology at the University of Chicago. Bob led Project Stormfury in the early 1960s, which explored the use of cloud seeding to modify hurricanes. Although Stormfury failed in its goal of reducing the destructiveness of hurricanes, the observational data and storm lifecycle research helped improve hurricane track and intensity forecasts. Bob went on to become the director of the National Hurricane Center (NHC) from 1967 - 1974.


Figure 1. Bob Simpson (seated) with (from left to right) NHC hurricane specialists Dan Brown, John Cangialosi, Eric Blake, Todd Kimberlain; hurricane scientist Dr. Bill Gray of Colorado State; and former NHC director Max Mayfield. Photo taken by Bill Thorson in April 2012 at the 30th Conference on Hurricanes and Tropical Meteorology of the American Meteorological Society in Ponte Verda Beach, Florida.

My experience hearing Dr. Simpson speak
I had the opportunity to hear Dr. Simpson speak back in April 2012, when he gave the opening talk at the 30th Conference on Hurricanes and Tropical Meteorology of the American Meteorological Society in Ponte Verda Beach, Florida. He was in amazing shape for a 99 year-old! He described his work with civil engineer Herb Saffir, who worked for the United Nations to develop low-cost housing all over the world that could withstand strong winds. Saffir and Simpson worked together, using data from aerial surveys of hurricane damage that began with Hurricane Audrey in 1957, to help develop their famous scale, which assigns a Category 1 through 5 rating to a storm based on its winds. The Saffir-Simpson scale was finally published in 1973, and gained widespread popularity after Neil Frank replaced Simpson as the director of NHC in 1974. The audience gave Dr. Simpson a standing ovation for making the effort to travel to the conference and give a talk.


Figure 2. Dr. Robert Simpson addresses the 30th Conference on Hurricanes and Tropical Meteorology of the American Meteorological Society on April 15, 2012, assisted by session chair Dr. Greg Holland.

Dr. Simpson and the Great 1919 Atlantic-Gulf Hurricane
In a remarkable 1989 interview conducted by hurricane scientist Dr. Ed Zipser of the University of Utah, Dr. Simpson related his experience with the great 1919 Atlantic-Gulf Hurricane, the year that he entered elementary school, which led to his life-long interest in hurricanes:

”I was attending the David Hirsh School on North Beach in Corpus Christi when the great 1919 hurricane struck— the worst Corpus Christi has ever experienced. As luck would have it, the hurricane arrived on a Sunday morning. If it had been on a school day, I would probably have been among the several hundred casualties, because the school building, which was sought out by residents as a shelter, was destroyed. In this hurricane we were all less impressed with the wind than with the spectacular rise of water. The storm surge, as viewed from our near-shoreline residence, arrived in two sudden rises. The first put water about two feet over downtown street levels and occurred in a matter of ten to fifteen minutes at most. The second came one to two hours later when, in a matter of minutes, flood levels rose 6-8 feet over street level. This began to flood the interior of our house which was built quite high. The family had to swim—with me on my father’s back—three blocks in near hurricane force winds to safe shelter in the courthouse— the only high building in the downtown area. A lot of what I saw frightened me, but also supplied a fascination that left me with a lifelong interest in hurricanes.”



Bob Simpson had a huge impact on hurricane science, and he will be greatly missed.

Jeff Masters

Hurricane

New World Record for Super Typhoon Haiyan: a 180-Ton Boulder Transported

By: JeffMasters, 3:46 PM GMT on December 18, 2014

On November 8, 2013, the world changed forever for the people of the Central Philippines. The strongest tropical cyclone at landfall on record in world history, Super Typhoon Haiyan, crashed ashore on the island of Samar, bringing a massive storm surge of 15 - 23 feet to the city of Tacloban. At least 6,300 people died, mostly due to the storm surge, making it the deadliest typhoon in modern Philippines history. Storm surge surveys published earlier this year revealed that high waves on top of the surge created high water marks of up to 46 feet above mean sea level—among the highest in world history. New research presented by Max Engel and co-authors from the University of Cologne in Germany at this week’s American Geophysical Union meeting in San Francisco, California found that Haiyan’s surge set another all-time record: the heaviest boulder known to be moved by a tropical cyclone. The team’s post-storm survey found a number of multi-ton boulders transported by the storm, with the heaviest being an incredible 180 metric tons. The huge boulder was shifted by 45 meters, parallel to the shore, by Haiyan’s storm surge. The boulder was on the shore near the town of Hernani, Samar Island, near where the remarkable storm surge video linked below was taken. Haiyan’s extreme storm surge was amplified by a long-wave phenomenon called infragravity waves or surf beat, Dr. Engel explained to me in an email, and that he and other researchers are not convinced anymore that a storm surge in the traditional sense, due to strong winds piling up a big dome of water, was that important in Eastern Samar.


Figure 1. Record-weight boulder (180 tons), 9 meters by 3.5 meters in size, transported by Super Typhoon Haiyan’s storm surge and waves. Image credit: Max Engel, University of Cologne, Germany.


Video 1. Nickson Gensis, Plan Philippines Community Development Worker, filmed from the top floor of a boarding house what is probably the most remarkable video of storm surge ever taken, during Super Typhoon Haiyan in Hernani, in Eastern Samar, Philippines on November 8, 2013. There is a remarkable tsunami-like storm surge observed at 46 seconds into the video.

Links
My May 2014 blog post, Super Typhoon Haiyan Storm Surge Survey Finds High Water Marks 46 Feet High.

My December 2013 blog post, Haiyan's Storm Surge: A Detailed Look.

Jeff Masters

Hurricane

Earth's 7th Warmest November Puts 2014 on Pace to be Warmest Year on Record: NOAA

By: JeffMasters, 5:47 PM GMT on December 15, 2014

November 2014 was the seventh warmest November on record, and the year-to-date-period January - November was Earth's warmest such period since record keeping began in 1880, said NOAA's National Climatic Data Center (NCDC) on Monday. NASA rated November 2014 as the 8th warmest November on record. November ended a 3-month streak with record warm monthly temperatures—August, September, and October 2014 were all the warmest such months on record. Global ocean temperatures during November 2014 were the warmest on record. This marks the seventh month in a row (beginning in May 2014) that the global ocean temperature broke its monthly temperature record. Global land temperatures in November 2014 were the 13th warmest on record. Global satellite-measured temperatures in November 2014 for the lowest 8 km of the atmosphere were the 8th or 2nd warmest in the 36-year record, according to Remote Sensing Systems and the University of Alabama Huntsville (UAH), respectively.


Figure 1. Departure of temperature from average for November 2014, the 7th warmest November for the globe since record keeping began in 1880. Australia, Austria, Italy, and Switzerland all set records for their warmest November on record. The coolest temperatures over land were recorded in the Eastern U.S. Image credit: National Climatic Data Center (NCDC) .


Figure 2. Global temperatures in 2014 compared to the previous five warmest years on record, dating back to 1880. After a relatively cool start, 2014 is now on pace the break the warmest year record set in 2010, according to NOAA. The years 2013 and 2014 are the only years on this list not to begin during a mature El Niño event. The years 1998 and 2010, each of which became the warmest year on record at the time, ended the year in a strong La Niña event, as evidenced by the relative fading of global average temperature later in the year. Image credit: NOAA/NCDC.

No billion-dollar weather disasters in November 2014
No billion-dollar weather-related disaster hit the Earth during November 2014, according to the November 2014 Catastrophe Report from insurance broker Aon Benfield. This is the first month since January 2012 without a billion-dollar weather disaster. The global number of billion-dollar weather disasters for the first eleven months of 2014 is 24. This is well behind the record-setting pace of 2013, which had 39 billion-dollar weather disasters by the end of November, and ended up with a record 41 by the end of the year.



No official El Niño, but unusual warmth in Eastern Pacific
Remarkably, the record-warm global sea surface temperatures over the past seven months have occurred in the absence of El Niño, a large-scale warming of the eastern and central equatorial Pacific Ocean that historically has been present whenever record global ocean temperatures have occurred. November 2014 officially featured neutral El Niño conditions in the equatorial Eastern Pacific, but sea surface temperatures rose to 0.5°C above average in mid-October 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 (each month being a 3-month average) for an El Niño event to be declared. The warmth in the Niño 3.4 region has continued into mid-December, standing at 0.9°C above average this week. Most models predict El Niño will be in place this winter and NOAA is continuing its El Niño Watch, giving a 65% chance of an El Niño event this winter. If an El Niño does emerge, it is likely to be a weak event.

Arctic sea ice falls to 9th lowest November extent on record
Arctic sea ice extent during November 2014 was the 9th lowest in the 36-year satellite record and was slightly above November 2013 levels, according to the National Snow and Ice Data Center (NSIDC).

Jeff Masters

CycloneCenter.org: Harnessing the Power of Crowd-Sourcing to Improve Hurricane Data

By: JeffMasters, 6:16 PM GMT on December 12, 2014

Today's guest post is by Dr. Jim Kossin, a hurricane scientist with NOAA's National Climatic Data Center stationed at the University of Wisconsin/NOAA Cooperative Institute for Meteorological Satellite Studies (CIMSS). I flew with Jim in 1988 with the NOAA Hurricane Hunters into Hurricane Gilbert of 1988, when it was the strongest Atlantic hurricane ever measured--888 mb. Jim was just a graduate student at the time, and has gone on since to write over 70 scientific papers, mostly on hurricane science.

- Jeff Masters


Has climate change made tropical cyclones stronger? This is a common question and it comes up even more often after a particularly devastating landfall event, such as Hurricane Katrina striking the U.S. Gulf coast in 2005 or Typhoon Haiyan moving over the Philippines in 2013. But it turns out that this is also a very difficult question to answer. The difficulty lies in the inconsistency of the available data. The data and their quality can change a lot from one time to the next and from one region of the globe to the next. This inconsistency means that we can never be sure whether a trend is real or just caused by the changes in the data.

Removing the inconsistencies is no easy job. And for data collected 50 to 100 years ago or more, there is relatively little that can be done with a high degree of confidence. Fortunately though, there is hope for improving things in the period of the modern satellite era, which began in the 1970s and really got going in the 1980s. In 1975, Vernon Dvorak, a scientist working at what is now the National Oceanic and Atmospheric Administration (NOAA) published a method that estimates tropical cyclone strength using satellite images.

At its heart, the method, known as the Dvorak Technique, is essentially a “pattern-recognition” routine. Images are assessed for certain shapes and patterns and these are then related to storm strength (Figure 1). The method has been applied all over the world for many years, but it has not been applied consistently and the satellite data has steadily improved in quality over time. The inconsistent application and progressively changing data quality creates a lot of uncertainty in any attempts at global trend analysis.


Figure 1. Satellite images of tropical cyclones of varying strength.

One thing we can do is go back and take all of the available satellite images of tropical cyclones from all of the world’s ocean basins, and “homogenize” them so that they all have about the same quality. We’ve actually already done this. Then we could recruit an expert at applying the Dvorak Technique and have him or her reanalyze all of the images from the past 30 to 40 years. Since it’s the same person doing it, there should be a high degree of consistency. When he or she is finished, we would have a more consistent global record of tropical cyclone intensity and we can see whether any trends show up. But there are about 300,000 images that need to be analyzed…assuming that it would take our expert a few minutes per image, that’s about 12 years working 8 hours a day, 5 days a week with no holidays!

A solution to this problem can be found in the concept of “crowd-sourcing”. In crowd-sourcing projects, large numbers of ordinary people attack an unwieldy problem together. The project can be a scientific one, as ours is, but the “crowd” doesn’t need to be scientists. What the individual “citizen scientist” may lack in formal training and experience can be made up for by having multiple evaluations by a large group. More evaluations means less uncertainty, and this is where the “power of the crowd” comes from. It’s been found, over and over again and in many situations, that a multitude of lay-people can provide more accurate answers than a small handful of experts.


Figure 2. The Cyclone Center home page.

The website cyclonecenter.org provides the platform for this solution (Figure 2). The Cyclone Center project began in September 2012, and since that time more than 20,000 citizen scientists have completed almost 400,000 image evaluations. But we still have a ways to go and we need your help. Please consider contributing to this ongoing and important project by visiting the Cyclone Center website and trying your hand as a citizen scientist. It’s fun to do and you can interact with other citizen scientists along the way. And you’ll know that you are contributing to finding the answer to the important question: are tropical cyclones getting stronger?

(A paper describing the Cyclone Center project and how successful it has been over the past two years has been accepted for publication in the Bulletin of the American Meteorology Society. An Early Online Release is available at http://journals.ametsoc.org/doi/abs/10.1175/BAMS-D-13-00152.1)

Jim Kossin, NOAA National Climatic Center

Hurricane

Torrential Rains Dent Califonia's Worst Drought in at Least 1,200 Years

By: JeffMasters, 1:25 PM GMT on December 11, 2014

Torrential rains are falling across much of drought-scarred California, thanks to the wettest storm to affect the U.S. West Coast since at least October 2009. The heavy rains will put a noticeable dent in the state's three-year drought, which was the worst 3-year drought drought period in at least the past 1,200 years. This startling figure comes from a study of tree rings by researchers Daniel Griffin and Kevin Anchukaitis, How unusual is the 2012-2014 California drought?, published in December 2014 in Geophysical Research Letters (press release and supplemental photos available here.) The scientists used tree ring data from blue oak trees in southern and central California to infer soil moisture levels, and thus drought. Blue oak tree ring widths are particularly sensitive to moisture changes. According to the authors, these tree rings show that 2014 was California's worst single year for drought in at least 1,200 years. Interestingly, they found that the amount of precipitation during 2012 - 2014 was not the lowest on record--more extreme three-year low precipitation periods occurred in 1898 - 1900, and in 1527 - 1529. But because the period 2012 - 2014 was by far the warmest 3-year period in California history, these record warm temperatures "could have exacerbated the 2014 drought by approximately 36%," they said. This bodes ill for the future, since global warming will bring an increase in the odds of record warm temperatures, and California has shown it can naturally have less precipitation than they had the past three years.

More detailed blog posts made this week on the research attempting to quantify the potential human contribution to California's drought are available from Dana Nuccitelli at the Guardian's "Climate Consensus - the 97% blog, and from Dr. Michael Mann at Huffington Post.


Figure 1. Kevin Anchukaitis (left) and Daniel Griffin (right) used tree-rings from centuries-old blue oak like the one pictured to provide long-term context for the ongoing California drought. 2014 image by Megan Lundin.


Figure 2. Super Soaker: A massive drought-denting extratropical storm soaks the U.S. West Coast as seen in this 4 pm PST December 10, 2014 satellite image. Image credit: NASA/GSFC.

Yosemite Park waterfalls resume flowing
Yosemite National Park's big waterfalls--Yosemite Falls, Bridalveil Fall, and Cascade Fall--resumed flowing again on December 3 after two days of significant rainfall in California's Yosemite area. "To see Yosemite Falls coming to life this morning is truly exhilarating," stated Don Neubacher, Yosemite National Park Superintendent on December 3. "This is a wonderful time to visit Yosemite National Park and the waterfalls just add to the magnificence of the park." The falls slowed to a trickle in mid-July and were completely dry for most of August, September, October, and November due to California's exceptional drought. You can view the falls on the Yosemite Falls webcam. Today's rains are sure to make the waterfall roar big-time!


Figure 3. Yosemite Falls on December 4, 2014 after a round of heavy rains got them flowing again (top) and what the falls looked like on December 1, 2014 during the peak of California's record drought (bottom.) Image credit: Yosemite Conservancy.


Video 1. ‪NatureRelaxation.com‬ just released this beautiful high definition journey to the magnificent and rejuvenating Yosemite Falls, photographed in 2011.

I'm on the road today to rainy San Francisco, where I'll be visiting the WU main office and attending next week's American Geophysical Union conference. As a result, my posts will be a little irregular for the next ten days.

Jeff Masters

Drought

Huge Rainstorm Poised to Ease California's Thirst

By: JeffMasters, 4:39 PM GMT on December 09, 2014

The wettest storm to affect the U.S. West Coast since 2009 is gathering strength over the Pacific Ocean, and promises to bring much-needed drought relief to thirsty California Wednesday through Friday. Rainfall amounts of 3 - 8 inches are expected over most of Northern California, with snowfall amounts of 1 - 3 feet predicted in the Sierra Mountains. As noted by Wunderground weather historian Christopher C. Burt in his Monday post, California Drought Situation Improves, this week’s storm may be the strongest and wettest storm to hit the region since October 2009, when the last major ‘pineapple express’ soaked the state. California is already benefiting from widespread heavy rains that fell November 29th through December 6th, and most of California is now running a seasonal precipitation surplus—the first time they’ve seen such since December 2012.


Figure 1. Predicted precipitation for the 7-day period ending December 16, 2014. Image credit: NOAA.


Figure 2. December 9, 2014 values of Total Precipitable Water—the amount of rain that would fall if one condensed all the water vapor in a column of air over one’s head. A very moist flow of air originating in the subtropics and flowing past Hawaii—the “Pineapple Express”—was headed towards the U.S. West Coast. Image credit: University of Wisconsin.


Figure 3. Observed snow pack in California’s Sierra Mountains averaged just 25% - 45% of normal for the date on December 8. Image credit: California Department of Water Resources.

Insufficient snow still a concern
This week’s rains will further improve the dire drought situation in California, though not as much as one might expect, since near-record warm temperatures have been reducing the amount of moisture falling as snow. A heavy snow pack in the Sierras is critical to reducing drought in California, since melting snow provides a much-needed source of water in the subsequent summer dry season. The first week of December was one of the warmest on record for much of California, with the average temperature running about 10°F above normal. This was due, in part, because of near-record sea-surface temperatures along the Californian Pacific Coastline, ranging from 59°-63°F—at least 5°F above average, and close to record warmth for this time of year. Snow levels during last week’s storm were generally above the 7,000-8,000’-foot level, and the Sierra snow pack on December 8 was just 25% - 45% of normal for the date. Snow levels from this week’s storm will start off above 7,000’, but will then lower to 5,000’, as much colder air than was seen during last week’s storm moves into the state. Hopefully, this will put the Sierra snowpack close to normal depth by mid-December.

Jeff Masters

Drought Flood

Hagupit Weakens to a Tropical Storm After Killing 21 in the Philippines

By: JeffMasters, 2:35 PM GMT on December 08, 2014

Light to moderate rains are falling in Manila, the capital of the Philippines, as a much-weakened Tropical Storm Hagupit plows west-northwest at 7 mph. Hagupit made landfall in Dolores, Eastern Samar Island, at 9:15 pm local time on Saturday as a Category 3 storm with 125 mph winds, and will finally exit the Philippines on Tuesday morning after dumping widespread rains of 10 - 15" across the Central Philippines. Some 2-day rainfall totals from the storm include 17.06" (433 mm) at Catbalogan and 15.55" (395 mm) at Borongan on Samar Island, and 9.14" (232 mm) on Masbate Island. At least 21 deaths are being blamed on the typhoon so far, but rescue workers have not yet reached remote areas that received heavy damage where the typhoon initially made landfall, on northern Samar Island. Satellite loops show a large but weakening tropical storm, with much reduced heavy thunderstorm activity. Nevertheless, Hagupit is still a very serious heavy rainfall threat. The storm's slow forward speed of 5 - 10 mph through the western Philippines will potentially bring heavy rains of 5 - 10" to Manila, with a population of about 12 million, causing serious flooding. However, it appears that the Philippines have avoided a major catastrophe on the scale of last year's Super Typhoon Haiyan, which left over 7,300 people dead or missing.


Figure 1. Flooding is seen in Barangay Tarabucan, Calbayog City, Samar, Dec. 7, 2014. (Fritz Pedrosa Tamondong/The Calbayog Journal) 


Figure 2. MODIS satellite image of Typhoon Hagupit over the Central Philippines at 04:50 UTC on Monday December 8, 2014. At the time, Hagupit had top winds of 60 mph. Image credit: NASA.


Figure 3. Predicted precipitation from Tropical Storm Hagupit from the 06 UTC Monday run of the GFDL hurricane model. Widespread areas of 8 - 16" (yellow colors) were predicted over the Manila metropolitan area, with some areas of 16+ inches predicted near where the storm makes landfall in Vietnam. Image credit: NOAA/GFDL.


Figure 4. Tropical Storm Hagupit over the Philippines as seen at 10 pm EST Sunday December 7, 2014 from the International Space Station. At the time, Hagupit had top winds of 70 mph. Image credit: Terry Virts.

Thanks for giving to Portlight's "Giving Tuesday and Beyond" campaign
Thanks go to everyone in the wunderground community who donated to disaster relief charity Portlight.org's month-long fundraising campaign, "Giving Tuesday and Beyond". Nearly $1,500 was donated, and I will be matching this donation to carry Portlight closer to their ambitious $20,000 fund raising goal for the month.

Jeff Masters

Hurricane

Category 1 Typhoon Hagupit Drenching the Philippines

By: JeffMasters, 4:43 PM GMT on December 07, 2014

Typhoon Hagupit was a weakened Category 1 typhoon with 85 mph winds and a 965 mb central pressure over the Central Philippines on Sunday morning, after making landfall in Dolores, Eastern Samar, at 9:15 pm local time on Saturday. At landfall, the Joint Typhoon Warning Center rated Hagupit a major Category 3 storm with 125 mph winds, and the Japan Meteorological Agency gave it a central pressure of 935 mb. On the island of Samar, Borongan received 15.55" (395 mm) of rain in just 24 hours, and Catbalogan got 14.18" (360 mm). Two deaths are being blamed on the typhoon so far, and it appears the islands avoided a major catastrophe.

Moderate wind shear of 10 - 20 knots and interaction with land will continue to slowly weaken Hagupit. Satellite loops show that the eye is no longer distinct and the cloud tops of the intense eyewall thunderstorms have warmed significantly, indicating weakening. Nevertheless, Hagupit is a very large and wet storm, and is still a very serious heavy rainfall threat. The storm's slow forward speed of 5 - 10 mph through the Philippines will insure that a large portion of the islands receive torrential rains of 10 - 15". Since Hagupit is likely to track very close to the capital city of Manila as a strong tropical storm or weak Category 1 typhoon, heavy rains of 10 - 15" could affect the southern portion of this city of 12 million. Hagupit's closest approach to Manila will come between 06 - 18 UTC on Monday.


Figure 1. MODIS satellite image of Typhoon Hagupit over the Central Philippines at 02:40 UTC on Sunday December 7, 2014. At the time, Hagupit was a Category 2 storm with 105 mph winds. Image credit: NASA.


Figure 2. Predicted precipitation from Typhoon Hagupit from the 06 UTC Sunday run of the GFDL hurricane model. Widespread areas of 8 - 16" (yellow colors), with some areas of 16+ inches were predicted. The capital of Manila was at the edge of the area expected to receive 8 - 16" of rain. Image credit: NOAA/GFDL.

Links
If you want to make a charitable donation to storm relief in the Philippines, consider a donation to DirectRelief. As discussed by Dr. Greg Laden in his blog, DirectRelief is a private humanitarian nonprofit organization based in Santa Barbara, California, with a mission to “improve the health and lives of people affected by poverty or emergency situations by mobilizing and providing essential medical resources needed for their care." They have three strategically pre-positioned typhoon modules with enough medicines and supplies supplies to treat 5,000 people for a month following the Hagupit disaster. DirectRelief's Hagupit web page is here.

Storm chaser James Reynolds is in the Philippines, and will be offering updates from Western Samar via his Twitter feed.

Latest storm news from Philippine news site rappler.com.

Storm surge expert Hal Needham has a blog post on the history of storm surges in the Philippines: The Philippines Has a History of Catastrophic, Fast-Moving Storm Surges.



Matching donation challenge: Portlight's "Giving Tuesday and Beyond" campaign
The Portlight.org disaster relief charity, founded and staffed by members of the wunderground community, has launched a month-long fundraising campaign called "Giving Tuesday and Beyond". They aim to raise $20,000 this month. I challenge the wunderground community to show their generosity this giving season: for each dollar donated between now and Monday, I pledge to make a matching donation. Here’s a sampling of what the money will go towards in 2015:

- Holding more Getting It Right conferences, starting in Hampton Roads, Virginia, in late February.

- Launching a traveling photo exhibit – “Disastrous: Left Behind” – in the lobby of FEMA’s headquarters in late January, with many more venues to follow around the country.

- Celebrating the 25th anniversary of the ADA on July 26th, 2015.

- Continuing to streamline their disaster response process in order to immediately respond better, faster, and smarter.

Portlight Strategies’ mission is to provide disaster services to the disability community, and to foster inclusive disaster planning and response for people with all types of disabilities. You can donate at the "Giving Tuesday and Beyond" campaign page. As always, you can visit the Portlight Blog or Portlight website to stay current on their latest efforts.


Video 1. ISS Flyover of Typhoon Hagupit at (4x speed) on December 6, 2014. Thanks go to wunderground member barbamz for posting this link in my blog comments.

Jeff Masters

Hurricane

Category 3 Typhoon Hagupit Hits the Philippines

By: JeffMasters, 4:37 PM GMT on December 06, 2014

Typhoon Hagupit made landfall in Dolores, Eastern Samar, at 9:15 pm local time on Saturday, December 6, said the Philippines State weather bureau PAGASA. At landfall, the Joint Typhoon Warning Center rated Hagupit a major Category 3 storm with 125 mph winds, and the Japan Meteorological Agency gave it a central pressure of 935 mb. Moderate wind shear of 10 - 20 knots and interaction with land helped to slowly weaken Hagupit before landfall. Satellite loops show that the eye is no longer distinct and the cloud tops of the intense eyewall thunderstorms have warmed, indicating weakening. Nevertheless, Hagupit is a very large and intense storm, and will be slow to weaken. The storm brought heavy rains of 1.79" (45 mm) in just one hour to Laoang Municipal Building, Northern Samar, ending at 10 pm local time Saturday.


Figure 1. MODIS satellite image of Typhoon Hagupit at 05:00 UTC on Saturday December 6, 2014. At the time, Hagupit was a Category 3 storm with 125 mph winds. Image credit: NASA.


Figure 2. Radar image of Typhoon Hagupit taken at 10:15 pm local time, one hour after landfall in Northern Samar Island in the Philippines. Image credit: Project NOAH.

Forecast for Hagupit: storm surge, high winds, and heavy rains are major threats
Hagupit will move west to west-northwest over the weekend at a slow forward speed of 5 -10 mph. The center will be over land much of the time, which will force the storm to weaken; moderate wind shear of 10 - 20 mph will aid this weakening process. Storm surge damage will be very heavy, as Project NOAH is predicting storm surge heights as high as 4.6 meters (15 feet) on the west side of Samar Island at Catbalogan. High winds will also cause widespread destruction, particularly to crops. However, the greatest danger from the storm may come from its rains. Hagupit's slow forward speed will allow torrential rains to fall for a long period of time, and widespread rainfall amounts of 10 - 15 inches are likely, with some mountainous areas receiving 15 - 25 inches. Since Hagupit is likely to track very close to the capital city of Manila as a strong tropical storm or weak Category 1 typhoon, heavy rains of 10 - 15" could affect this heavily populated part the country resulting in yet another billion-dollar typhoon disaster for the Philippines. Hagupit's closest approach to Manila will likely come around 06 UTC on Monday. In addition, special lahar warnings have been put out for mudslides for two volcanoes along Hagupit's path, Mayan and Bulusan, whose flanks have unstable ash deposits from recent eruptions. A total of 650,000 people have been evacuated for Hagupit, and I am hopeful this effort will keep the death toll relatively low.


Figure 3. Predicted precipitation from Typhoon Hagupit from the 06 UTC Saturday run of the GFDL hurricane model. Widespread areas of 8 - 16" (yellow colors), with some areas of 16+ inches were predicted. The capital of Manila was in an area expected to receive 10 - 15" of rain. Image credit: NOAA/GFDL.

Links
If you want to make a charitable donation to storm relief in the Philippines, consider a donation to DirectRelief. As discussed by Dr. Greg Laden in his blog, DirectRelief is a private humanitarian nonprofit organization based in Santa Barbara, California, with a mission to “improve the health and lives of people affected by poverty or emergency situations by mobilizing and providing essential medical resources needed for their care." They have three strategically pre-positioned typhoon modules with enough medicines and supplies to treat 5,000 people for a month following the Hagupit disaster. DirectRelief's Hagupit web page is here.

Storm chaser James Reynolds is in Calbayog on the west coast of Samar Island in the Philippines, which will receive a direct hit from Hagupit. He is offering updates via his Twitter feed.

Latest storm news from Philippine news site rappler.com.

Storm surge expert Hal Needham has a new blog post on storm surge observations from Hagupit, plus a post on the history of storm surges in the Philippines.



Matching donation challenge: Portlight's "Giving Tuesday and Beyond" campaign
The Portlight.org disaster relief charity, founded and staffed by members of the wunderground community, has launched a month-long fundraising campaign called "Giving Tuesday and Beyond". They aim to raise $20,000 this month. I challenge the wunderground community to show their generosity this giving season: for each dollar donated between now and Monday, I pledge to make a matching donation. Here’s a sampling of what the money will go towards in 2015:

- Holding more Getting It Right conferences, starting in Hampton Roads, Virginia, in late February.

- Launching a traveling photo exhibit – “Disastrous: Left Behind” – in the lobby of FEMA’s headquarters in late January, with many more venues to follow around the country.

- Celebrating the 25th anniversary of the ADA on July 26th, 2015.

- Continuing to streamline their disaster response process in order to immediately respond better, faster, and smarter.

Portlight Strategies’ mission is to provide disaster services to the disability community, and to foster inclusive disaster planning and response for people with all types of disabilities. You can donate at the "Giving Tuesday and Beyond" campaign page. As always, you can visit the Portlight Blog or Portlight website to stay current on their latest efforts.


Video 1. ISS Flyover of Typhoon Hagupit at (4x speed) on December 6, 2014. Thanks go to wunderground member barbamz for posting this link in my blog comments.

Jeff Masters

Hurricane

Super Typhoon Hagupit Closes in on the Philippines

By: JeffMasters, 4:16 PM GMT on December 05, 2014

Heavy rains and huge waves are already pounding the Philippines and over half a million people have been evacuated as Super Typhoon Hagupit closes in on the storm-weary islands. Hagupit briefly fell below the 150 mph wind threshold needed to maintain its "Super Typhoon" designation on Thursday, but is intensifying once again. At 9 am EST Friday, Hagupit was a very dangerous Category 4 super typhoon with 150 mph winds and a central pressure of 915 mb. Hagupit--Filipino for "Smash"--exploded into a mighty Category 5 storm with 180 mph winds and a central pressure of 905 mb on Wednesday, but weakened on Thursday due to moderate wind shear of 10 - 20 knots, plus an eyewall replacement cycle that caused the inner eyewall to collapse and be replaced by an outer eyewall with a larger diameter. An eyewall replacement cycle often causes a temporary weakening of a tropical cyclone, followed by a re-strengthening as the storm consolidates around its new eyewall. That appears to be the case with Hagupit, which microwave satellite images show has now finished its eyewall replacement cycle. Satellite loops showed that the typhoon had a larger 17-mile diameter eye surrounded by very intense eyewall thunderstorms that were expanding in areal coverage and intensity early Friday morning (U.S. time). However, this intensification process had halted by late Friday morning. Hagupit is over warm ocean waters of 29°C (84°F) and is under moderate wind shear of 15 knots. The eyewall is not as intense on the south side, due to shearing action of strong upper-level winds from the southeast.



Figure 1. Visible (top) and infrared (bottom) VIIRS images of Super Typhoon Hagupit from the Suomi satellite at 04:40 UTC December 4, 2014. At the time, Hagupit was a peak-strength Category 5 storm with 180 mph winds. Image credit: Dan Lindsey, NOAA/NESDIS/CIRA/Colorado State.

Forecast for Hagupit: not as bad as Haiyan, but still devastating
Super Typhoon Haiyan made landfall on November 7, 2013 in Samar Island in the Philippines as the strongest landfalling tropical cyclone ever rated by the Joint Typhoon Warning Center--winds of 190 mph. Haiyan left 7,300 people dead or missing in the Philippines, destroying about 1 million houses and displacing some 4 million people. Leyte Island's city of Tacloban (population 200,000) suffered the greatest casualties, thanks to a 20+’ storm surge. With warm waters and moderate wind shear expected until landfall, but with increasing interaction with land, Hagupit will likely be a Category 4 storm with sustained winds between 135 - 155 mph at landfall. This is far weaker than Haiyan was, but no cause for celebration. Extreme damaging winds, a large and deadly storm surge, and torrential rains causing massive flooding and dangerous mudslides are all of great concern from Hagupit. Wind damage and storm surge damage are primarily of concern on Samar Island, which is likely to receive a direct hit from the eyewall of the powerful storm; Hagupit will likely make landfall about 50 - 100 miles north of where Haiyan hit last year. However, the greatest danger from the storm might be its rains. Hagupit will move very slowly though the Philippines at about 5 - 10 mph, which will allow torrential rains to fall for a long period of time. Widespread rainfall amounts of 10 - 15 inches can be expected, with some areas receiving 15 - 25 inches. Since Hagupit is likely to track very close to the capital city of Manila as a strong tropical storm or weak Category 1 typhoon, heavy rains will affect the most heavily populated part the country. In addition, Special lahar warnings have been put out for mudslides along the flanks of two volcanoes along Hagupit's path, Mayan and Bulusan, whose flanks have unstable ash deposits from recent eruptions.


Figure 3. Predicted precipitation from Super Typhoon Hagupit from the 06 UTC Friday run of the GFDL hurricane model. Widespread areas of 8 - 16" (yellow colors), with some areas of 16+ inches were predicted. Image credit: NOAA/GFDL.

Links
Storm chaser James Reynolds is in the Philippines, and reported on Friday morning (U.S. time) that high waves were already pounding the east coast of Samar, lapping at roads and houses. He will will be offering updates from Western Samar via his Twitter feed.

Storm surge expert Hal Needham has a new blog post: The Philippines Has a History of Catastrophic, Fast-Moving Storm Surges.



Matching donation challenge: Portlight's "Giving Tuesday and Beyond" campaign
The Portlight.org disaster relief charity, founded and staffed by members of the wunderground community, has launched a month-long fundraising campaign called "Giving Tuesday and Beyond". They aim to raise $20,000 this month. I challenge the wunderground community to show their generosity this giving season: for each dollar donated between now and Monday, I pledge to make a matching donation. Here’s a sampling of what the money will go towards in 2015:

- Holding more Getting It Right conferences, starting in Hampton Roads, Virginia, in late February.

- Launching a traveling photo exhibit – “Disastrous: Left Behind” – in the lobby of FEMA’s headquarters in late January, with many more venues to follow around the country.

- Celebrating the 25th anniversary of the ADA on July 26th, 2015.

- Continuing to streamline their disaster response process in order to immediately respond better, faster, and smarter.

Portlight Strategies’ mission is to provide disaster services to the disability community, and to foster inclusive disaster planning and response for people with all types of disabilities. You can donate at the "Giving Tuesday and Beyond" campaign page. As always, you can visit the Portlight Blog or Portlight website to stay current on their latest efforts.

Jeff Masters

Hurricane

Cat 5 Super Typhoon Hagupit Poised to Hit Philippine Islands Devastated by Haiyan

By: JeffMasters, 4:32 PM GMT on December 04, 2014

Super Typhoon Hagupit has exploded into mighty Category 5 storm with 175 mph winds and a central pressure of 905 mb, and is threatening the same portion of the Philippine Islands devastated by Super Typhoon Haiyan in November 2013. The spiral bands of the massive storm are already bringing gusty winds and heavy rain showers to Samar and Leyte Islands, which bore the brunt of Haiyan’s massive storm surge and incredible winds--rated at 190 mph at landfall on November 7, 2013 by the Joint Typhoon Warning Center. Haiyan killed over 7,000 people in the Philippines, with Tacloban (population 200,000) suffering the greatest casualties, thanks to a 20+’ storm surge. Thousands of people still live in tents in Tacloban in the wake of Haiyan, and mass evacuations have begun to get these vulnerable people to safety.


Figure 1. An infrared VIIRS image of Super Typhoon Hagupit from the Suomi satellite at 15:55 UTC December 3, 2014, revealed a structure very similar to that of the standard hurricane symbol (lower right.) At the time, Hagupit was an intensifying Category 4 storm with 150 mph winds. Image credit: Dan Lindsey, NOAA/NESDIS/CIRA/Colorado State.

Forecast for Hagupit
Hagupit is over very warm ocean waters of 29 - 30°C (84 - 86°F) and is under moderate wind shear of 15 - 20 knots. Satellite loops show that Hagupit has a prominent 14-mile diameter eye, and a large area of very intense eyewall thunderstorms with cold cloud tops. The eyewall is lopsided, due to winds on the east side of the storm causing wind shear of 15 - 20 knots and and interfering with development of the thunderstorms on the east side of the storm. Thursday morning microwave images indicate that Hagupit is likely undergoing an eyewall replacement cycle, where the inner eyewall shrinks, collapses, and is replaced by an outer eyewall with larger diameter. This process will likely cause a modest weakening of Hagupit, to perhaps 150 mph winds, by Friday. But with warm waters and moderate wind shear expected until landfall, Hagupit should be able to make landfall as a very dangerous Category 4 typhoon in the Central Philippines. The ridge of high pressure steering Hagupit has weakened since Wednesday, forcing the storm to slow its forward speed from 21 mph to 14 mph. The trough of low pressure passing to the north that is weakening the ridge will move eastwards past the Philippines on Friday, which will potentially allow the ridge to build back in stronger than before, and force Hagupit on a more westerly path—or even west-southwesterly path—as it approaches landfall on Samar or Leyte Island near 12 UTC Saturday. Most of the models that had shown Hagupit recurving to the north and missing the Philippines have now followed the lead of the reliable European model, which has been consistently showing landfall in the Central Philippines. The latest 12Z Thursday runs of our two most reliable models, the GFS and European, are now very close, showing a landfall in southern Samar Island, just north of where Haiyan hit in November 2013. If this track hold true, it would avoid a major storm surge disaster in Tacolban like Haiyan brought. Extreme winds, a large and deadly storm surge, and torrential rains causing massive flooding and dangerous mudslides are all of great concern for where Hagupit makes landfall.


Figure 2. MODIS satellite image of Typhoon Hagupit at 02:10 UTC on Thursday December 4, 2014. At the time, Hagupit was a Category 5 storm with 180 mph winds. Image credit: NASA.

Hagupit is Earth's seventh Category 5 storm of 2014
Hagupit is Earth's seventh Category 5 storm of the year, making it the busiest year for these most extreme of tropical cyclones since 2005. In that year, eleven Category 5s were recorded (4 in the Atlantic, 2 in the Western Pacific, 3 in the South Indian, and 2 in the South Pacific.) Hagupit is the fifth Category 5 in the Western Pacific in 2014, and the fourth with a pressure of 915 mb or lower, as rated by the Japan Meteorological Agency. The last time four or more typhoons reached that intensity was 1997, when five did so. The other Category 5 storms of 2014:

Super Typhoon Nuri hit 180 mph winds east of Japan on November 3. The Japan Meteorological Agency put Nuri's lowest central pressure at 910 mb. The extratropical remounts of Nuri went on to bomb into one of the most intense extratropical storms ever observed in the waters near Alaska, with a central pressure of 924 mb.

Super Typhoon Vongfong also had 180 mph winds south of Japan. Vongfong battered Japan's Okinawa Island on October 9 - 10, killing 11 and doing $58 million in damage. The Japan Meteorological Agency put Vonfong's central pressure at 900 mb at the storm's peak intensity, the lowest pressure it has given to a storm since Super Typhoon Haiyan's 895 mb pressure in November 2013.

Super Typhoon Halong topped out at 160 mph winds with a central pressure of 920 mb on August 3, eventually making landfall in Japan on August 10 as a tropical storm. Halong killed 12 and did $4 million in damage.

Super Typhoon Genevieve (160 mph winds, 915 mb pressure) did not affect land.

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 be 2014’s eighth Category 5 storm in post-season reanalysis.

The Eastern Pacific had one Cat 5 in 2014 that did not affect land: Marie (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. Since 1996, only two years have had more than eight Category 5 storms in one year: 1997 (thirteen) and 2005 (eleven.)

Our database of these most extreme of tropical cyclones is of poor quality and there are not enough of them to say if they are showing climate-related trends yet or not, but the forecast is for more of these high-end tropical cyclones to occur in a warmer climate. The 2013 IPCC report predicts that there is a greater than 50% chance (more likely than not) that we will see a human-caused increase in intense hurricanes by 2100 in some regions, and the 2014 U.S. National Climate Assessment said “Hurricane-associated storm intensity and rainfall rates are projected to increase as the climate continues to warm.”

Jeff Masters



Hurricane

Category 3 Typhoon Hagupit Threatening Philippine Islands Hit by Haiyan

By: JeffMasters, 4:22 PM GMT on December 03, 2014

Category 3 Typhoon Hagupit put on a respectable burst of rapid intensification over the past day, and is steaming west-northwest at 21 mph towards the same portion of the Philippine Islands devastated by Super Typhoon Haiyan in November 2013. Hagupit is over very warm ocean waters of 30°C (86°F) and is under light wind shear around 10 knots--conditions which favor intensification into a 150-mph super typhoon by Thursday. The ridge of high pressure steering Hagupit will weaken late this week, putting the typhoon into a region of weak steering currents, making the threat to the Philippines uncertain. The storm will slow down and potentially turn north, keeping the core of the typhoon well out to sea, as predicted by this morning's 00Z and 06Z runs of the GFS model. Most concerning are the recent runs of the usually-reliable European model, which has been consistently showing a landfall near 18 UTC Saturday very close to Tacloban on Leyte Island, which endured the brunt of Super Typhoon Haiyan's fury. However, if Hagupit does hit the Philippines, it will be a much weaker storm than Haiyan was. There is less heat energy available in the ocean for Hagupit, and wind shear is expected to rise to the high range on Friday as strong upper-level winds tear at the storm. Heavy rains, not high winds and storm storm surge, will likely be the greatest threat for the Philippines from Hagupit.


Figure 1. MODIS satellite image of Typhoon Hagupit at 04:30 UTC on Wednesday December 3, 2014. At the time, Hagupit was a Category 3 storm with 115 mph winds. Image credit: NASA.

Less ocean heat energy available to Hagupit compared to Haiyan
As I discussed in my November 13, 2013 post, Super Typhoon Haiyan's Intensification and Unusually Warm Sub-Surface Waters, when Super Typhoon Haiyan exploded into one of the most powerful storms ever recorded on Earth, the mighty storm took advantage of some unusually warm sub-surface waters. Haiyan intensified into a Category 5 super typhoon with 195 mph sustained winds, as rated by the Joint Typhoon Warning Center on November 7, 2013. Haiyan tracked over surface waters that were of near-average warmth, 29.5 - 30.5°C (85 - 87°F), but the waters at a depth of 100 meters (328 feet) beneath Haiyan during its rapid intensification phase were a huge 3°C above average, according to Professor I-I Lin of the Department of Atmospheric Science at the National Taiwan University. The sub-surface waters east of the Philippines have warmed dramatically over the past twenty years. According to Pun et al. (2013), "Recent increase in high tropical cyclone heat potential area in the Western North Pacific Ocean", the depth to where ocean temperatures of at least 26°C (79°F) penetrates has increased by 17% since the early 1990s, and the Tropical Cyclone Heat Potential has increased by 13%. The warm-up is due to an increase in the surface winds blowing across the region--the trade winds--which have caused a southward migration and strengthening of the North Equatorial Current (NEC) and the North Equatorial Counter Current (NECC). However, during the past few months, the trade winds have weakened in the Western Pacific, as the ocean has moved towards an El Niño-like state (as of this week, ocean temperatures in the Eastern Pacific had reached the threshold of "moderate" El Niño conditions.) Weaker east-to-west blowing surface winds means that warm water in the Western Pacific can slosh eastwards towards South America, resulting in a weaker North Equatorial Current in the waters east of the Philippines, and less warm water and heat energy to fuel typhoons threatening those islands.


Figure 2. Ocean temperatures at a depth of 100 meters (328 feet) on December 1, 2013 (top), shortly after the passage of Super Typhoon Haiyan, and on December 1, 2014 (bottom.) Note how weaker east-to-west trade winds near the surface in 2014 have led to a weaker North Equatorial Current, resulting in much cooler waters to the east of the Philippines compared to in 2013. Image credit: Japan Meteorological Agency.

Jeff Masters

Hurricane

The 2014 Atlantic Hurricane Season Ends With Below-Average Activity

By: JeffMasters, 4:36 PM GMT on December 01, 2014

The 2014 Atlantic hurricane season is officially in the books, ending up with below average activity--8 named storms, 6 hurricanes, 2 intense hurricanes, and an Accumulated Cyclone Energy (ACE) that was 63% of the 1981 - 2010 median. The 2014 numbers were below the 1981 - 2010 average of 12 named storms, 6 hurricanes, and 3 major hurricanes, and way below the averages from the active hurricane period 1995 - 2013: 15 named storms, 8 hurricanes, and 4 major hurricanes, with an ACE index 151% of the median. The death and damage statistics for the 2014 Atlantic hurricane season were gratifyingly low: there were only five deaths (four from Hurricane Gonzalo in the Lesser Antilles and one from Tropical Storm Dolly in Mexico), and total damages from all storms were less than $500 million. The quiet season was due to an atmospheric circulation that favored dry, sinking air over the tropical Atlantic, and high wind shear over the Caribbean. Sea Surface Temperatures were also near-average--considerably cooler than what we've gotten used to since the active hurricane period that began in 1995.


Figure 1. Tracking chart for the 2014 Atlantic hurricane season. Image credit: NHC.

Some notable facts from the 2014 Atlantic hurricane season, as provided by Philip Klotzbach and Bill Gray of Colorado State:

- For the ninth consecutive year, no major hurricanes hit the U.S., marking the first time since records began in 1851 the U.S. has gone that long without a Category 3 or stronger hurricane hitting. The previous record was eight years, set in 1861 - 1868. Wilma of 2005 was the last major hurricane to hit the U.S., and was also the last hurricane to hit Florida.

- For the ninth consecutive year, Florida went without a hurricane strike. This is Florida's longest hurricane-free stretch since records began in 1851. The previous longest hurricane-free streak in Florida was five years, set in 1980 - 1984.

- Arthur was the strongest storm (Category 2 at landfall) to hit the U.S. since Hurricane Ike (also Category 2 at landfall) in 2008.

- Strongest hurricane: Hurricane Gonzalo, 145 mph winds, 940 mb pressure.

- Most damaging hurricane: Hurricane Gonzalo, $200 - $400 million damage in Bermuda.

- Longest-lived named storm: Edouard, 7.75 days as a named storm.

- The eight named storms were the fewest since 1997.

- Vertical wind shear (200-850-mb) during July-September in the Caribbean (10-20°N, 90-60°W) was 11.3 meters per second, which was the strongest since 1986 (11.6 meters per second).

- More ACE was accrued during October (30 units) than during August and September combined (29 units). The last time that this happened was 1963.

- The pre-season forecasts made by the major forecast groups at NOAA, Colorado State, TSR, Penn State, Florida State, WSI, the UKMET office, and NC State all did well. These forecasts called for a near-average to below-average Atlantic hurricane season.


Figure 2. Hurricane Gonzalo as seen from the International Space Station on October 16, 2014. At the time, Gonzalo was at peak strength, with 145 mph winds. Gonzalo was the first Atlantic hurricane to reach sustained winds of at least 145 mph since Hurricane Igor of 2010, and made it all the way to 50.7°N latitude as a hurricane, which is the farthest north a hurricane has made it since Hurricane Debby of 1982 (50.8°N.) Its remnants battered the United Kingdom on October 21 with wind gusts exceeding 100 mph, and killed three people there. Image credit: Alexander Gerst.

Tropical Storm Hagupit forms in the Western Pacific
Over in the Western Pacific, typhoon season is still in swing, as Tropical Storm Hagupit has formed about 1500 miles east of the Philippines. Hagupit is expected to take advantage of very warm waters and low wind shear to intensify into a major Category 3 typhoon later this week. Hagupit may be a threat to the Philippines this weekend, as suggested by the 00Z Monday morning run of the European model, but the GFS model predicts that the storm will recurve to the north and miss the Philippines.

Wunderground member CycloneOz has put together a 15-minute YouTube animation of all of the IR satellite imagery from the Atlantic this hurricane season.

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.

Category 6™

About

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