Category 6™

Great earthquake rocks Chile; NYC gets 4th greatest snow ever; Xynthia batters Europe

By: JeffMasters, 5:26 PM GMT on February 27, 2010

A great earthquake with magnitude 8.8 rocked the coast of Chile at 6:34 GMT this morning, generating a potentially dangerous tsunami that is racing across the Pacific Ocean. The great quake is the 7th most powerful tremor in world history (Figure 1). Preliminary tsunami wave heights for the California coast near Santa Barbara are 2 - 2.5 feet. The wave is expected to arrive between 12:15 - 12:35 pm PST. The tsunami is expected to arrive in Hawaii between 11:05 - 11:42am HST, with a wave 8.2 feet high expected in Hilo, on the Big Island. A tsunami from the 9.5 Magnitude 1960 earthquake in Chile killed 61 people in Hilo. Today's quake was so strong, that it triggered a seiche in Lake Pontchartrain, Louisiana, over 4,500 miles (7,000 km) away. The lake sloshed back and forth, creating a wave 0.4 - 0.51 feet on either side of the lake.


Figure 1. Wikipedia's list of strongest earthquakes of all-time.

Preliminary tsunami amplitude forecasts:

La Jolla, CA 2.3 ft
Los Angeles, CA 2.0 ft
Malibu, CA 2.6 ft
Pt. San Luis, CA 2.3 ft
Half Moon Bay, CA 2.6 ft
Crescent City, CA 1.7 ft
Morro Bay, CA 2.2 ft
Santa Monica, CA 3.3 ft
San Francisco, CA 0.7 ft
Pismo Beach, CA 4.6 ft

Hilo, HI 8.2 feet 11:5am HST
Honolulu, HI 1.6 ft 11:37am HST
Kahului, HI 7.2 ft 11:26am HST
Nawiliwili, HI 3.0 ft 11:42am HST
Haleiwa 1.6 ft
Kawaihae 2.0 ft

Port Orford, OR 0.7 ft

Moclip, WA 1.3 ft

Seward, AK 1.3 ft
Stika, AK 1.3 ft
Kodiak, AK 2.3 ft

Tofino, British Columbia 1.7 ft

Today's great quake occurred at the boundary between the Nazca and South American plates about 325 km southwest of the capital Santiago (population 5.3 million). The depth was estimated at 35 km. At least four aftershocks of magnitude 6 or higher have occurred, the largest being a 6.9 aftershock. Fortunately, the area close to the epicenter is relatively sparsely populated, but there may be heavy damage in Concepción (est. pop. 300,000) and Chillan (est. pop. 170,000), which lie 115 km and 100 km to the south of the epicenter, respectively.


Figure 2. NOAA's preliminary forecast of tsunami wave energy for today's earthquake. Image credit: NOAA Tsunami Warning Center.

New York City slammed with its 4th largest snowstorm on record
The snow from the fourth extreme snowstorm to wallop the Northeast U.S. this winter dumped a remarkable 20.9" of snow on New York City's Central Park yesterday and Thursday. This is the 4th largest snowstorm for the city in recorded history. According to the National Weather Service, the top ten snowstorms on record for New York City's Central Park are:

26.9" Feb 11-12, 2006
26.4" Dec 26-27, 1947
21.0" Mar 12-14, 1888
20.9" Feb 25-26, 2010
20.2" Jan 7-8, 1996
19.8" Feb 16-17, 2003
18.1" Mar 7-8, 1941
17.7" Feb 5-7, 1978
17.6" Feb 11-12, 1983
17.5" Feb 4-7, 1920

The storm also helped New York City set a new all-time snowfall record for the most snow ever recorded in a month--36.9". The old record was 30.5", set in March 1896. However, the old Lower Manhattan WB Station recorded 37.9" in February 1894. Yesterday's snowstorm puts New York City's snow for the 2009 - 2010 season at 51.4", making it the 11th snowiest winter since 1869. Chris Burt, author of Extreme Weather, lists the city's all-time seasonal snowfall record at 81.5", set in the winter of 1867 - 1868. This measurement came before official records began in Central Park, and were done be the NY Park Commissioners (see "Annual Report NY Park Commissioners", 1868, by John B. Marie). The second snowiest winter in NYC occurred during the winter of 1995 - 1996, when 75.6" fell.

Destructive Winter Storm Xynthia battering Portugal and Spain
A powerful 969 mb low pressure system named "Xynthia" is rapidly intensifying of the coast of Spain, and stands poised to deliver a devastating blow to Portugal, Spain, and France today and tomorrow as it powers through Europe. Sustained winds of 60 mph (96 km/hr) were reported today at a Personal Weather Station in Costa del Morte, Spain. The pressure fell to 969 mb as Xynthia passed overhead. For comparison, Winter Storm Klaus had a minimum pressure of 967 mb. Klaus, which hit northern Spain and southwest France January 23 - 25, was Earth's most costly natural disaster of 2009, causing $5.1 billion in damage and killing 26. Models predict that Xynthia will continue to intensify today, reaching 962 mb as it moves into the west coast of France Sunday morning. Sustained winds of 50 - 65 mph (80 - 105 km/hr) with hurricane-force gusts up to 100 mph (160 km/hr) are possible along the north coast of Spain tonight and the west coast of France on Sunday as Xynthia barrels through. The storm is also bringing an exceptionally moist plume of tropical moisture ashore, as seen in precipitable water imagery from NOAA (Figure 4). This moisture is likely to cause moderate to severe flooding in portions of Europe over the weekend.


Figure 3. Visible satellite image at 12 GMT of Xynthia.


Figure 4. Satellite measurements show a region of extremely high atmospheric moisture is associated with Winter Storm Xynthia. This moisture will surge over Portugal and Spain today, potentially creating serious flooding. Image credit: Sheldon Kusselson, NOAA/NESDIS.

Links to follow:
Wundermap for Northwest Spain
Spanish radar
Meteo-France
Portugese radar

Jeff Masters

Winter Weather

Heavy snow, high winds, flooding for the Northeast; destructive Winter Storm Xynthia nears Europe

By: JeffMasters, 4:12 PM GMT on February 26, 2010

A major winter storm continues to pound the northern Mid-Atlantic and Northeast U.S. today, as a powerful 979 mb low pressure system stalled out over Long Island Sound brings heavy snow, flooding rains, and high winds to the region. The storm dropped more than two feet of snow over Eastern New York near Albany, and surrounding regions of Western Massachusetts and Southern Vermont. One location in Vermont, West Halifax, received over three feet of snow--38.5". Heavy rains in excess of three inches has fallen over large sections of Northeast, including 8.38" at Scarborough, Maine. Rivers have spilled out of their banks over sections of Connecticut, Rhode Island, Massachusetts, and southwestern Maine, resulting in many road closures. Sustained winds of 25 - 40 mph have been common all along the coast, with wind gusts in excess of 60 mph common in the Appalachian Mountains. The prize for most extreme weather goes to New Hampshire's Mount Washington. At midnight, the Mount Washington Observatory reported sustained winds of 104 mph, gusting to 123, visibility zero in moderate snow, and a temperature of 21°F.

Fourth greatest snow for New York City, and still accumulating
The storm has dumped 20.8" of snow on New York City's Central Park as of 1pm EST today, making it the 4th largest snowstorm for the city in recorded history. With another 1 - 3 inches likely for the city today, the storm should rank as the 3rd largest snowfall on record before it's over. According to the National Weather Service, the top ten snowstorms on record for New York City's Central Park should now read:

26.9" Feb 11-12, 2006
26.4" Dec 26-27, 1947
21.0" Mar 12-14, 1888
20.8" Feb 25-26, 2010
20.2" Jan 7-8, 1996
19.8" Feb 16-17, 2003
18.1" Mar 7-8, 1941
17.7" Feb 5-7, 1978
17.6" Feb 11-12, 1983
17.5" Feb 4-7, 1920


Figure 1. Total radar-estimated precipitation from this week's storm over Maine. A large swath of 4+ inches of precipitation has fallen on a wet snowpack, creating flooding problems.

Today's storm will linger and slowly weaken through Saturday, bringing an additional 6+ inches of snow over portions of southeast New York, western Connecticut, and western Massachusetts. The strong winds will die down by tonight, aiding the efforts of utility repair crews struggling to keep up with all the power outages created by combination of high winds and wet, heavy snow.

Next storm
The active storm pattern isn't going to change over the few weeks for the Eastern U.S. The next potential snowstorm will be Tuesday, and will affect the Southeast U.S. Although it is too early to be confident of the amount or type of precipitation this storm will bring, snow will be a possibility for northern Alabama, northern Georgia, and portions of North and South Carolina.

Destructive Winter Storm Xynthia headed for Europe
A large 1000 mb low pressure system named "Xynthia" is over the eastern Atlantic, and is expected to rapidly intensify Saturday morning into a meteorological "bomb" that will bring high winds and flooding rains to Portugal, northern Spain, and western France. The models are coming into better agreement now, and have shifted their position for the storm's maximum intensity eastwards. France is now in the bullseye, and the storm is predicted to be at maximum intensity on Sunday morning when it will be positioned over northwestern France. The storm's powerful cold front will sweep ashore south of the low, bringing sustained winds of 50 - 60 mph (80 - 95 km/hr) to the coast of France's Bay of Biscay, with gusts over hurricane force (120 km/hr). The central pressure at that time will range from 966 mb to 972 mb, according to two of our top computer models, the ECMWF and GFS. This is about the same intensify as last year's Winter Storm Klaus. Klaus, which hit northern Spain and southwest France January 23 - 25, was Earth's most costly natural disaster of 2009, causing $5.1 billion in damage and killing 26. Klaus peaked in intensity at 967 mb, and brought wind gusts of 120 mph (193 km/hr) to Formiguères, France, 125 mph (200 km/hr) to Portbou, Spain, and 134 mph (216 km/hr) to Port d'Envalira, Andorra. Meteo-France has put out a bulletin warning of the possibility of hurricane-force wind gusts on Sunday, and is recommending that residents limit travel and avoid the threatened areas if the forecasts remains on track. While the storm is not expected to be as intense when it moves over Portugal and northern Spain on Saturday, these regions will still receive tropical storm-force wind with gusts to hurricane force. The Spanish Meteorological Agency is warning of the possibility of 100 mph (160 km/hr) wind gusts over northern Spain on Saturday. The damage total from this weekend's storm over all of Europe will probably exceed $1 billion, making it the globe's second billion-dollar weather disaster of 2010. The first was the back-to-back blizzards over the U.S. Mid-Atlantic region earlier this month, which are being blamed for over $2 billion in insured losses, according to Eqecat, a risk management firm.


Figure 2. Visible satellite image of Xynthia.


Figure 3. Forecast from the 1am EST 2/26/10 run of the GFS model for 00 GMT Sunday for surface winds. The GFS is predicting that Saturday's storm will peak in intensity at this time with a pressure of 972 mb. Sustained winds just below hurricane force of 60 - 75 mph (green colors) are expected offshore from France. Image was generated using our wundermap for France with the "model" layer turned on.

Links to follow:
La Palma, Canary Islands was reporting sustained winds of 33 mph, gusting to 45 mph today.
Wundermap for Northwest Spain
Spanish radar
Meteo-France
Portugese radar
Meteored.com Spanish weather forum
Portugese weather forum
French weather forum

Portlight continues relief efforts in Haiti
The damage from last month's catastrophic earthquake in Haiti has now been estimated at $7.2 billion to $13.2 billion, according to a study released last week by the Inter-American Development Bank. This figure is 1 - 2 times the $7 billion GDP of Haiti estimated by the World Bank. In the face of such a massive disaster, every little bit of help is needed, and Portlight.org has been doing a fantastic job getting relief into Haiti for those who need it most. Below is a link to a 3-minute long piece E News did on Portlight's efforts in Haiti:



Other press:
Much-Needed Rehab Equipment Obtained through Portlight.org, from the Real Medicine Foundation Blog.

Bill Ranic's Blog

The Portlight disaster-relief effort continues in Haiti, and please visit the Portlight.org blog to learn more and to donate.

Next post
I'll have a post this weekend.

Jeff Masters

Winter Weather

Heavy snow, rain, and flooding for the Northeast U.S.

By: JeffMasters, 3:21 PM GMT on February 25, 2010

The winter of 2009-2010 continues its relentless onslaught over the U.S. today, as a powerful low pressure system intensifying along the East Coast brings heavy snow, flooding rains, and high winds to New England and the Mid-Atlantic. The storm has already dropped more than two feet of snow over Eastern New York near Albany, and surrounding regions of Western Massachusetts and Southern Vermont. These regions are now seeing rain mixed in with the snow, which will limit further accumulations to 1 - 3 inches. Farther east, flooding is a concern for most of Connecticut, Massachusetts, Rhode Island, southern New Hampshire, and portions of western Maine, where heavy rainfall of 1 - 3 inches on top of a snow pack with a high water content has created runoff that has already swollen many rivers to flood stage. Heavy snow is the main concern over southeast New York, northern New Jersey, and northeast Pennsylvania. The unusually slow-moving storm is expected to drop snow amounts of up to 18" in the Pocono Mountains of northeast Pennsylvania, and in northern New Jersey. New York City, whose 30.5" of snow so far this winter is 13" above average for this date, could get up to a foot of wet, heavy snow. Philadelphia's 73" of snow for the season will get an 8 - 12" boost from the storm, taking their record snowiest winter even further into record territory. Wind gusts of 30 - 40 mph in combination with the very wet, heavy snow will make power outages a problem over much of the region.


Figure 1. Visible satellite image at 9:30am EST Thursday, February 25, 2010 showing today's Northeast U.S. snowstorm. Image credit: NASA GSFC GOES project.

Some selected storm-total snowfall amounts, from Tuesday morning through 10am EST today, courtesy of the National Weather Service:

...CONNECTICUT...
BURLINGTON 10.0
NEW HARTFORD 3.8 W 9.0

...KENTUCKY...
OVEN FORK 1 NE 5.0
BLEDSOE 2 SE 4.0

...MASSACHUSETTS...
SAVOY 28.5
ROWE 25.0
CHESTERFIELD 24.0
ASHFIELD 23.6
HEATH 22.0
SHELBURNE 22.0
PLAINFIELD 21.5
PITTSFIELD 20.0
BECKET 19.8
CHESTER 19.5
BLANDFORD 19.0
ASHBURNHAM 16.8
LANESBOROUGH 16.0
NORTH OTIS 16.0
NEW ASHFORD 13.0
WORCESTER 10.7

...NEW HAMPSHIRE...
EAST LEMPSTER 20.0
WASHINGTON 18.5
PETERBOROUGH 18.0
RANDOLF 17.6
GREENFIELD 16.0
NEWPORT 15.3
WILTON 14.0
BENNINGTON 13.0
WAPOLE 12.9
WEST CHESTERFIELD 10.8
LEMPSTER 10.0

...NEW YORK...
ALTAMONT 26.5
WESTERLO 26.0
WILLARD MTN BASE 25.0
NORTH HEBRON 24.0
MEDUSA 23.0
MORIAH 22.5
TABORTON 22.0
DURHAM 20.0
PORTER CORNERS 20.0
ROXBURY 18.9
PHOENICIA 18.5
CHATHAM CENTER 18.0
SCHENECTADY 15.0
ALBANY 12.4
BINGHAMTON 10.5

...OHIO...
CARROLOTON 5.5

...PENNSYLVANIA...
PONOCO PEAK LAKE 13.0
HAWLEY 3.8 NE 11.0
WANTAGE 11.0
PLEASANT MOUNT 10.0
DINGMANS FERRY 3.9 WSW 9.2
MILANVILLE 1.5 SE 8.9
SAYLORSBURG 8.5
BEEMERVILLE 8.0
EAST STROUDSBURG 8.0
THOMPSON 8.0

...RHODE ISLAND...
BURRILLVILLE 6.5
WEST GLOCESTER 5.1
WOONSOCKET 0.3 W 3.4

...TENNESSEE...
APPALACHIA 3.0
ROAN MOUNTAIN 3.0

Update on this Saturday's major winter storm in Europe
Computer forecast models continue to forecast the development of a powerful winter storm that will rapidly intensify Saturday morning into a meteorological "bomb" that will bring high winds and flooding rains to Portugal, northern Spain, and possibly France. However, today's model runs are less aggressive in deepening the storm, and no longer call for the storm to be as intense as last year's Winter Storm Klaus. Klaus, which hit northern Spain and southwest France January 23 - 25, was Earth's most costly natural disaster of 2009, causing $5.1 billion in damage and killing 26. Klaus peaked in intensity at 967 mb, and brought wind gusts of 120 mph (193 km/hr) to Formiguères, France, 125 mph (200 km/hr) to Portbou, Spain, and 134 mph (216 km/hr) to Port d'Envalira, Andorra. Last night's 00Z (7pm EST) run of the ECMWF model and GFS model called for Saturday's storm to have 974 - 976 mb central pressure. Saturday's storm still has the potential to be plenty damaging, as winds of tropical storm force with gusts to hurricane force should affect a large swath of Portugal and northern Spain.


Figure 2. Forecast from the 1am EST 2/25/10 run of the GFS model for 18 GMT Saturday for surface winds. The GFS is predicting that Saturday's storm will peak in intensity at this time with a pressure of 974 mb. Sustained winds just below hurricane force of 60 - 75 mph (green colors) are expected offshore from Portugal. Image was generated using our wundermap for Spain with the "model" layer turned on.

Next post
My next post will be Friday.

Jeff Masters

Winter Weather

Europe braces for destructive weekend winter storm

By: JeffMasters, 3:05 PM GMT on February 24, 2010

A large but disorganized extratropical storm located over the middle-Atlantic Ocean is expected to move rapidly eastwards towards Spain over the next two days. As the storm approaches Spain on Friday, it is expected to tap into a cold polar airmass to its north and rapidly intensify into a meteorological "bomb"--a mighty winter cyclone with hurricane force winds. Though sea surface temperatures off the coast of Spain are about 1°C below average, the waters of 12 - 16°C will provide plenty of moisture and energy to the powerful storm, which may end up rivaling last year's Winter Storm Klaus in intensity. Klaus, which hit northern Spain and southwest France January 23 - 25, was Earth's most costly natural disaster of 2009, causing $5.1 billion in damage and killing 26. Klaus peaked in intensity at 967 mb, and brought wind gusts of 120 mph (193 km/hr) to Formiguères, France, 125 mph (200 km/hr) to Portbou, Spain, and 134 mph (216 km/hr) to Port d'Envalira, Andorra.


Figure 1. Visible satellite image of the Atlantic at 8am EST Wednesday, February 24, 2010. A developing extratropical cyclone over the middle Atlantic threatens to bring hurricane-force wind gusts to Spain and Portugal on Saturday. Meanwhile, a snowstorm over the New England is dumping heavy snows there. Image credit: NASA GSFC GOES project.

This Saturday's storm is expected to follow a track very similar to Klaus, reaching maximum intensity at 18 GMT Saturday as it passes just north of Spain and Portugal (Figure 2). If the storm tracks near or over the northwest corner of Spain as most of the models are predicting, the cyclone's powerful cold front will likely bring sustained winds of 50 - 60 mph with damaging hurricane-force wind gusts and flooding rains to northern Spain and Portugal. The latest 06Z (1am EST) run of the GFS model predicts that this weekend's storm will bottom out at a pressure of 968 mb, about the same minimum pressure achieved by last year's destructive Winter Storm Klaus (967 mb). The latest 06Z run of the Navy NOGAPS model is more aggressive, deepening the storm into a 948 mb monster that misses Spain by several hundred miles, but comes ashore over Ireland Sunday morning with a pressure of 956 mb. This is a central pressure typically found in Category 2 hurricanes! (Note, though, that extratropical systems generally do not generate winds as strong as a hurricane with a similar central pressure, since extratropical storms do not form an eyewall with extreme winds like a hurricane does). The NOGAPS is currently an outlier, though, and the other models such as the ECMWF, Canadian, and UKMET do not foresee the storm getting that intense. Even so, this weekend's storm has the potential to be a multi-billion dollar weather disaster for Europe.




Figure 2. Forecast from the 1am EST 2/24/10 run of the GFS model for 18 GMT Saturday for mean sea level pressure and 6-hour precipitation (top) and surface winds (bottom). The GFS is predicting that Saturday's storm will peak in intensity at this time with a pressure below 968 mb. Sustained winds of 70 - 75 mph (yellow green colors in bottom plot) are expected just offshore of Portugal. Images generated using our wundermap for Spain with the "model" layer turned on.

The winter storm-fest continues for the U.S.
This winter's relentless winter storm-fest over the U.S. continues this week, with a powerful cyclone over the Northeast U.S. expected to bring 2 - 3 feet of snow to the mountains of New Hampshire and Vermont. The storm is wrapping in too much warm air to bring heavy snow to the major cities along the coast, where most of the precipitation will fall as rain. Next Tuesday, a powerful low pressure system is expected to bring heavy rains to Florida, with the possibility of snow falling in northern Georgia and surrounding regions.

Next post
My next post will be Thursday or Friday.

Jeff Masters

Winter Weather

Russia's Pole of Cold hits -70°F: Europe's 2nd coldest reading of all-time

By: JeffMasters, 4:48 PM GMT on February 22, 2010

The notorious Russian winter, bane of the armies of Napoleon and Hitler, has been in classic form during the winter of 2010 . Brutal cold has been the rule this winter in the European portion of Russia, and at 9am local time on Friday, February 19, the town of Hoseda-Hard, Russia hit a remarkable -70°F (-56.4°C)--the second coldest temperature ever measured in Europe. Hoseda-Hard is located in extreme northeastern Europe, 90 miles (145 km) south of the Arctic Ocean and about 150 miles (240 km) west of the Ural Mountains and the boundary of Asia. The town lies in a shallow river valley (elevation 84 meters) where cold air tends to pool. The surrounding region is known as Europe's "Pole of Cold". The coldest temperature ever recorded in Europe was an extraordinary -72.6°F (-58.1°C) in the Pole of Cold's Ust'Schugor (64.15°N 57.45°) on December 31, 1978. The nearby city of Pechora, the largest city in the region (population: 50,000), is also well-known for its extreme temperatures. Pechora boasts Europe's third coldest temperature, a -68.8°F (-56.0°C) reading observed on February 9, 1946. It is likely that Hoseda-Hard got a degree or two colder than the remarkable -70°F measured on Friday, since the station only reported temperatures once every three hours. The high temperature Friday in Hoseda-Hard was a not-so-balmy -49°F (-45°C)!


Figure 1. Departure of surface temperature from average for February 19, 2010. Temperatures at Europe's "Pole of Cold" (dark purple colors) were more than 40°F (22°C) below average. The white dot marks the location of Hoseda-Hard, Russia, which recorded a remarkable -70°F (-56.4°C) at 9am local time that day--the second coldest temperature ever measured in Europe. Image credit: NOAA/ESRL.


Figure 2. A monument in Europe's "Pole of Cold" near Hoseda-Hard, Russia, marking the location of the Arctic Circle. Image credit: Mactak.

Exceptional February heat in Africa
I credit weather historian and extreme weather expert Chris Burt, author of Extreme Weather, for pointing out the incredible cold in Russia on Friday. Chris also noted that on Saturday, February 20, the temperature in Birni-N'Konni, Niger hit 112°F (44.3°C). This is just 3°F (1.7°C) below the warmest temperature ever recorded in the Northern Hemisphere in February--the 115°F reading from Abeche, Chad (date unknown).

Next post
My next post will be Tuesday or Wednesday.

Jeff Masters

Winter Weather

January 2010: extremes and monthly summary

By: JeffMasters, 2:33 PM GMT on February 19, 2010

The globe recorded its fourth warmest January since record keeping began in 1880, according to NOAA's National Climatic Data Center. NASA's Goddard Institute for Space Studies rated January 2010 as the 2nd warmest January on record, behind January 2007. January 2010 global ocean temperatures were the 2nd warmest on record, next to 1998. Land temperatures in the Southern Hemisphere were the warmest on record, but in the Northern Hemisphere, they were the 18th warmest. The relatively cool Northern Hemisphere land temperatures may have been due to the well-above average amount of snow on the ground--January 2010 snow cover in the Northern Hemisphere was the 6th highest in the past 44 years. Global satellite-measured temperatures for the lowest 8 km of the atmosphere were the warmest on record in January, according to both the University of Alabama Huntsville (UAH) and RSS data sets. This was the second time in the past three months that the UAH data set has shown a record high global atmospheric temperature.


Figure 1. Departure of surface temperature from average for January 2010. Image credit: National Climatic Data Center.

A few notable global weather highlights from January 2010:

According to the United Kingdom's Met Office, the U.K. as a whole had its coolest January since 1987 and the eighth coolest January since records began in 1914. Scotland had its coolest January since 1979. During the first two weeks of January, the Irish Republic experienced a spell of extreme cold weather that began in mid-December, resulting in the most extreme cold spell over Ireland since early 1963, according to the Irish Meteorological Service. Most places of the Irish Republic had its coolest January since 1985 and the coolest January since 1963 in the Dublin area.

A rare summer snowfall occurred on January 18th in the town of Bombala, New South Wales, Australia. The town received a light dusting of accumulation, marking the first summer snow in the high terrain of southeast Australia since records began in 1965. The town has an elevation of around 3,000 feet (900 meters) above sea-level. Forecasters said that snow at such low elevations is unusual at any time of year, especially summer. Six days before the snow, temperatures had hit 37°C (99°F) in Bombala.

Eleven inches (28 cm) of snow fell in Seoul, South Korea on the 3rd, marking the greatest snowfall amount for that city since records began in 1937 (Source: BBC).

Central Beijing, China received 3 inches (8 cm) of snow on the 2nd, the most for a single day since January 1951, while suburbs of the city reported 13 inches (33 cm). Over 90 percent of flights at Beijing.s International Airport were affected. On January 6th, temperatures in Beijing dropped to -16.7°C (1.9°F), the lowest minimum temperature in the first ten days of January since 1971.


Figure 2. An unusual sight: Virtually all of Britain was covered by snow on January 7, 2010. Image credit: NASA.

January 2010: near-average temperatures in the U.S.
For the contiguous U.S., the average January temperature was 0.3°F above average, making it the 55th coolest January in the 115-year record, according to the National Climatic Data Center. The U.S. has been on quite a roller coaster of temperatures over the past four months--the nation recorded its third coldest October on record, followed by its third warmest November, followed by its 14th coolest December, followed by an average January. The coolest January temperature anomalies were in Florida, which had its 10th coldest such month. The Pacific Northwest was very warm, with Oregon and Washington recording their 4th warmest January on record. Seattle experienced its warmest January since records began in 1891.


Figure 3. Ranking of temperatures by state for January 2010. Florida had its 10th coldest January on record, while Washington and Oregon had their 4th warmest. Image credit: National Climatic Data Center.

U.S. drought
Precipitation across the U.S. was near average in January. Notably, Arizona had its 5th wettest January and New Mexico its 7th wettest. The only state much drier than average was Michigan, which had its 8th driest January. At the end of January, 3% of the contiguous United States was in severe-to-exceptional drought, a decrease of 4% from the previous month. This is the lowest drought footprint for the country since detailed drought statistics began in 1999.

U.S. records
A few notable records set in the U.S. during January 2010, courtesy of the National Climatic Data Center::

All-time low pressure records were set across most of California, Arizona, Nevada, and southern Oregon on January 20 - 21. This was approximately 10 - 15% of the area of the U.S.

Arizona set its all-time 24-hour state snowfall record: 48" at Sunrise Mountain Jan. 21 - 22.

The 50.7 inches (129 cm) that fell in Flagstaff, AZ Jan. 16 - 23 was the third highest five-day total ever recorded there.

Yuma, Arizona's total of 2.44 inches of rain (62 mm) was their 2nd greatest January total ever, narrowly missing the record of 2.49 (63 mm) set in 1949. Their daily total of 1.95 (50 mm) inches on the 21st was the greatest one-day January total ever.

Near Wikieup, AZ, the Big Sandy River crested at 17.9 feet, washing away numerous roads and setting a new all-time record crest, breaking the previous record of 16.4 feet set back in March 1978.

Burlington, VT had its largest single snowstorm on record, 33.1" on Jan. 1 - 3.

Sioux City, IA tied its all-time max snow depth record (28" on Jan. 7).

Beckley, WV had its snowiest January on record (40.9"; old record 37.3" in 1996)

Bellingham, Washington tied its record highest January temperature of 65°F on January 11.

Hondo, Texas tied its record coldest January temperature of 12°F on January 9.

Cotulla la Salle, Texas tied its record coldest January temperature of 16°F on January 9.

Records were broken or tied at Daytona Beach, Orlando, Melbourne, and Vero Beach Florida for the greatest number of consecutive days in which the daily high temperature remained below 60 degrees F (15.5 C). Daytona Beach's string was twelve days.

Jackson, KY and London, KY tied their record for longest streak of consecutive days falling below 32°F (11 days). Pensacola, FL had its 2nd longest such streak (10 days), and Mobile, AL its 3rd longest (10 days).

Key West, FL had its 2nd coldest temperature ever measured, 42°F. The record is 41°F, set in 1981 and 1886.

Moderate El Niño conditions continue
Moderate El Niño conditions continue over the tropical Eastern Pacific. Ocean temperatures in the area 5°N - 5°S, 120°W - 170°W, also called the "Niña 3.4 region", were at 1.2°C above average on February 10, in the middle of the 1.0°C - 1.5°C range for a moderate El Niño, according to the Australian Bureau of Meteorology. The strength of El Niño has been roughly constant for the first two weeks of February. A burst of westerly winds that developed near the Date Line in January has pushed eastwards towards South America over the past month, and this should keep the current El Niño at moderate strength well into March. All of the El Niño models forecast that El Niño has peaked and will weaken by summer. Most of the models predict that El Niño conditions will last into early summer, but cross the threshold into neutral territory by the height of hurricane season.

January sea ice extent in the Arctic 4th lowest on record
January 2010 Northern Hemisphere sea ice extent was the 4th lowest since satellite measurements began in 1979. Ice extent was lower than in 2009 and 2008, but greater than in 2005, 2006, and 2007, according to the National Snow and Ice Data Center (NSIDC). The weather pattern over the Arctic in the first half of January 2010 featured a strongly negative Arctic Oscillation (AO). This pattern tends to slow the winds that typically flush large amounts of sea ice out of the Arctic between Greenland and Iceland. In this way, a negative AO could help retain some the second- and third-year ice through the winter, and potentially rebuild some of the older, multi-year ice that has been lost over the past few years. However, the ice pack is the thinnest on record for this time of year, and much above average temperatures this summer would likely cause a new record summertime sea ice loss.

Next post
My next post will be Monday or Tuesday.

Jeff Masters

Climate Summaries

Warmest January on record for the lower atmosphere

By: JeffMasters, 2:37 PM GMT on February 17, 2010

Earth's lower atmosphere recorded its warmest January on record last month, according to data from both the University of Alabama, Hunstville (UAH) and Remote Sensing Systems (Figure 1). The satellite measurements used to take the global temperature of the lower atmosphere began in December 1978, using the Microwave Sounding Unit (MSU) on polar-orbiting satellites. The January 2010 temperature anomaly was an impressive 0.72°C above the 1979 - 1998 average, easily beating the previous record of 0.59°C set in January 2007. Last month's anomaly was the 3rd warmest anomaly for any month, falling just 0.04°C cooler than the record warmest anomalies of 0.76°C from February and April 1998. The January 2010 satellite-measured temperatures continued a trend of very warm conditions we've seen in the lower atmosphere since the current El Niño event began in June 2009. Record high temperatures occurred in November 2009, and were the second highest on record in both July and September 2009, according to UAH. The record-breaking temperatures in the lower atmosphere are due to the heating of the atmosphere by the strong El Niño event that has been heating the waters of the Central and Eastern Pacific since June 2009, combined with the global warming trend of the past few decades. Since we are currently at the lowest level of solar output in decades, the Earth is currently about 0.1°C cooler than if we were near the maximum of the 11-year sunspot cycle. Had we been near solar maximum, we would have set an all-time warmest lower atmosphere temperature anomaly record last month.(Note, though, that there is about a 2-year time lag between solar maximum and when Earth's global temperature responds). It will be interesting to see if the current El Niño event, which is quite a bit weaker than the record-strongest El Niño of 1998, is capable of making 2010 beat 1998 for honors as the warmest year on record in the lower atmosphere.


Figure 1. Temperature of the lowest 8km of the atmosphere measured by satellite via the MSU instrument flown on polar-orbiting satellites between 1979 - 2010. Image credit: Dr. Roy Spencer, University of Alabama, Hunstville.

Real-time display of atmospheric temperatures measured by satellite
The University of Alabama, Huntsville has a handy interactive plotting page that lets one plot up the historical and near-real-time satellite measurements of Earth's global average temperature at various levels of the atmosphere. These temperatures are measured by the MSU instrument on the polar-orbiting NOAA-15 satellite. Note that this is a different instrument than the AQUA satellite's MSU instrument used by UAH to formulate their official monthly global temperature anomaly data set. The two satellites give similar results, although NOAA-15 requires an additional correction to account for drift of the satellite.


Figure 2. Temperature of the global atmosphere at 14,000 feet (4.4 km) as measured by the MSU instrument on the polar-orbiting NOAA-15 satellite. This instrument has been flying since August 1998. The 20-year average (yellow line) and 20-year record highs (pink line) are for the period 1979 - 1998, using versions of the MSU instrument that flew on older satellites. The most recent data (green line), as of February 15, 2010, are marked by a white square, and have now fallen below the record for the date set in 1998. Note that during July 2009, November 2009, and January 2010, record high temperatures were measured at 14,000 feet altitude. A full description of the data is available from the University of Alabama, Hunstville.

Error sources in global atmospheric temperatures measured by satellite
Satellite-measured temperatures of Earth's atmosphere, in my judgment, are inferior to using the surface based system of ground stations and ocean buoys for measuring global temperature changes. I have two reasons for saying this:

1) The satellite temperatures show large global increases when there is an El Niño event. While the surface also experiences an upward spike in temperatures during an El Niño, it is much less pronounced than the atmospheric heating that occurs. Since we live at the surface, those temperatures are more relevant.

2) According to a description of the MSU data available on the Remote Sensing Systems web site where the data is archived,


"The instruments in the MSU series were intended for day to day operational use in weather forecasting and thus are not calibrated to the precision needed for climate studies. A climate quality dataset can be extracted from their measurements only by careful inter-calibration of the eleven distinct MSU instruments."


In other words, it's very tricky to make an accurate measurement of Earth's temperature going back to 1979, when satellite measurements began. You have to merge data from eleven separate satellites, whose instruments were never designed to make the kind of precise long-term climate measurements that are being asked of them. While surface stations also have error sources, I believe that the uncertainty in the satellite-based global temperature measurements are higher.

Dr. John Christy of the University of Alabama, Huntsville, made a series of efforts to perform the careful inter-calibration needed beginning in the 1990s, and for over a decade successfully defended his conclusion that the MSU instruments were showing a much lower level of tropospheric warming than what climate models predicted. Christy was probably the most quoted scientist by the "greenhouse skeptics" during that period, and testified numerous times before Congress about his findings. This discrepancy was a prime argument Senator James Inhofe (R-Oklahoma) used in his famed 2003 speech when he referred to the threat of catastrophic global warming as the "greatest hoax ever perpetrated on the American people." Greenhouse contrarian Dr. S. Fred Singer, who has probably more Congressional testimony about global warming under his belt than any other scientist, headlined his SEPP website for many years with the quote, "Computer models forecast rapidly rising global temperatures, but data from weather satellites and balloon instruments show no warming whatsoever. Nevertheless, these same unreliable computer models underpin the Global Climate Treaty." Michael Crichton also used the tropospheric warming discrepancy to give climate models a bad rap in his State of Fear novel. However, a series of papers published in 2004 and 2005 showed that the satellite inter-calibration methods used by Christy were incorrect. Christy conceded that his analysis had been in error, and participated in writing a statement put out by NOAA's Climate Change Science Program that detailed the error.

Climate change contrarians continue to prefer using the UAH satellite data to look at global temperature trends, since that data set shows less warming than the regular surface station data sets, and rates 1998 as the warmest year on record. The UAH data shows that in the 31-year period from 1979 - 2009, Earth's lower atmospheric temperature warmed by 0.13°C per decade. A separate analysis of the satellite data by Remote Sensing Systems (RSS) puts this number at 0.15°C per decade. For comparison, NASA's GISS and the UK HadCRUT surface data sets (which don't use satellite data) show warming of 0.16°C and 0.15°C per decade, respectively. You can generate these numbers yourself, using the excellent woodfortrees.org plotting tools. The amount of global warming predicted in the 2007 IPCC report for the period 2010 - 2030 was 0.20°C per decade, so we are running about 25% below this predicted level of warming, when averaging over the past 31 years.

For further reading: I have a 2006 blog post on this, and realclimate.org has a technical discussion.

Portlight continues relief efforts in Haiti
The Portlight.org disaster-relief effort continues in Haiti, with another container of specifically-requested medical supplies being shipped today. At the request of Portlight's on-site coordinator, Richard Lumarque, Portlight is committed to sending another container with 500 tents plus food and water. The cost of each shipment is $4300, so your donations are greatly appreciated! Please visit the Portlight.org blog to learn more and to donate. Floodman's blog has the latest info on Portlight's plan for Haitian relief.


Figure 3. Richard Lumarque, Portlight's on-site coordinator in Haiti, poses with double-amputee Darline Exidor, who received a wheelchair from Portlight. Portlight's team of ten relief workers has been laboring full-time the past two weeks to deliver donated supplies and assess the needs of the earthquake survivors.

Next post
I'll have a new post on Thursday or Friday.

Jeff Masters

Climate Change

Winter Olympics forecast: near-record warmth

By: JeffMasters, 3:28 PM GMT on February 15, 2010

Under sunny skies and warm southwest winds the temperature in Vancouver, British Columbia climbed to 54°F (12.4°C) yesterday, just missing the record of 12.9°C (55°F) for the date, set in 1991 (records in Vancouver go back to 1937). That was marvelous weather for all the joggers that were out in t-shirts and shorts in Vancouver yesterday, but is lousy weather if you're trying to hold a Winter Olympics. The men's downhill was postponed yesterday and rescheduled for today, because of rain and bad snow. The women's combined, originally scheduled to run Saturday, has been postponed until Thursday. The mountain has been getting snow at the top, a mix of snow and rain along the middle section, and rain at the bottom, making for very difficult skiing conditions. Practice runs have been mostly been canceled. In West Vancouver, where the moguls competition was held yesterday, snow had to be trucked and helicoptered in because there wasn't enough on the ground. The snow-making machines weren't any help, because it was too warm to make snow. Too bad Philadelphia or Washington D.C. didn't make a bid for the Winter Olympics! It's an upside-down winter when Canada has trouble getting snow, and Washington D.C. gets five feet.

As we can see from a plot of the temperature departure from average for the month of January (Figure 1), most of Canada has seen very unusual warmth, with temperatures over 5°C (9°F) covering large swathes of the country.


Figure 1. Departure of January temperature from average for the strong to moderate strength El Niño year of 2010 (left), and a composite of the last five years that had a moderate to strong El Niño (right). Note that typically, an El Niño event brings much warmer than average temperatures to Vancouver, and cooler than average conditions to Florida. This year has seen an extreme amplification of this pattern. The impact of the Arctic Oscillation (AO) is evident over eastern Canada and Greenland, where exceptionally warm temperatures were recorded. Image credit: NOAA/ESRL.

Why all the warmth in Vancouver? El Niño partly to blame
So, what's going on? The average high temperature in Vancouver this time of year is typically 8°C (46°F). Vancouver has seen above-average temperatures every day this month, and tied one daily record so far. This unusual February warmth follows a record warm month of January, which averaged 3°C (5.4°F) above average, beating the previous record set in 2006 by a pretty significant margin, 0.9°C (1.6°F). Nearby Seattle, Washington had its warmest January in 120 years of record keeping, and both Oregon and Washington recorded their 4th warmest January. As we can see from a plot of the temperature departure from average for the month of January (Figure 1), most of Canada saw very unusual warmth, with temperature anomalies over 5°C (9°F) covering large swathes of the country. Record warm January temperatures were observed not only over British Columbia, but also over Manitoba and over much of Quebec, where half of the province's twelve largest cities experienced their warmest or second warmest January on record. Unusual Canadian warmth is to be expected during a moderate to strong El Niño episode, which is what we've had this winter in the Eastern Pacific Ocean. The pattern we've seen during the previous five moderate to strong El Niños dating back to 1987 (Figure 1, right) shows this trend, and also the trend towards colder than average conditions in Florida. However, the pattern for January 2010 shows an extreme amplification of this El Niño pattern. We had record warmth over much of Canada, and Florida got socked with its 10th coldest January on record. The extreme amplification of the January temperature pattern was due in part to the influence of the Arctic Oscillation/North Atlantic Oscillation, a natural wind pattern over the North Atlantic measured by the difference in pressure between Iceland and ocean areas to the south. That difference in pressure was remarkably small in the first half of January, leading to the weakest Arctic Oscillation pattern in 60 years of record keeping. This allowed cold air to spill southwards into Florida, and helped bring very warm temperatures to Greenland and Eastern Canada. El Niño, combined with the Arctic Oscillation, all superimposed upon exceptionally warm global temperatures, is probably the best explanation for the record January warmth in Canada. Globally, January 2010 was the 4th warmest January on record, with global ocean temperatures the 2nd warmest on record, according to NOAA.

The forecast: near-record warmth for Vancouver
The forecast for Vancouver for the remainder of the week calls for temperatures above 10°C (50°F) each day. Today's forecast high of 10°C (50°F) will approach the record high for the date of 12.6°C (55°F). The long range forecast through the remainder of the Winter Olympics promises continued near-record warmth, as the jet stream is projected to stay in its current El Niño-type pattern. In this configuration, a strong ridge of high pressure stays anchored over the Pacific coast, allowing plenty of warm air from the southwest into British Columbia. Unfortunately for the winter games, I expect that Vancouver will end up experiencing its 1st or 2nd warmest February on record.

No major snowstorms in sight
Today's snowstorm for the mid-Atlantic has shifted northwards, meaning the that the maximum 4 - 8 inches of snow from this storm will pass north of snow-weary Philadelphia, Washington D.C., and Baltimore. The computer models are showing that this will be the last significant snow storm to affect the eastern half of the U.S. for at least a week, and residents of the Mid-Atlantic can look forward to a slow but steady melting of their huge piles of snow. This is exactly what is needed to avoid a serious flooding situation--a rapid thaw or large rainstorm would have been a major problem.

Next post
I'll have a new post on Wednesday at the latest. I did an interview with the Washington Post weather blog by the "Capital Weather Gang", for those interested.

Jeff Masters

Winter Weather

The United States of Snow

By: JeffMasters, 5:51 PM GMT on February 13, 2010

We live in the United States of Snow. A rare Deep South heavy snowstorm whipped across the southern tier of states yesterday, dumping six-plus inches of snow over portions of Louisiana, Mississippi, Alabama, Georgia, South Carolina, and North Carolina. Even Florida got into the act, with up to two inches recorded in the extreme northwestern Panhandle. The snowstorm left 49 of the 50 states with snow cover, according to an article by Associated Press. Hawaii was the lone hold-out. David Robinson, head of the Rutgers Global Snow Lab, said that 67.1% of the U.S. had snow cover on Friday morning, with the average depth a respectable 8 inches. Normally, the U.S. has about 40 - 50% snow coverage during the 2nd week of February. January had the 6th greatest snow cover in the 44-year record over the contiguous U.S., and December 2009 had the most snow cover of any December on record. The current pattern of record heavy snows over the the Eastern U.S. is primarily due to a natural oscillation in the Earth's climate system called the North Atlantic Oscillation (NAO). (Some prefer to discuss this in terms of the Arctic Oscillation, which is as a close cousin of the NAO, and one can use either). I discussed the NAO's influence on winter weather in a post last month. Another contributing factor is probably the current moderate El Niño event.

An all-time record snow for Dallas
The most recent storm clobbered Dallas with 12.5" of snow, the heaviest snow on record for the Dallas-Fort Worth Airport. Dallas' previous record was 7.4", set on January 15 - 16, 1964. The 15.7" of snow that has now fallen on Dallas this winter eclipses the previous record seasonal snowfall for the city--14.1" during the winter of 1977 - 1978. The snowstorm dumped over a foot of snow along a narrow region just north of Dallas and Fort Worth, with the towns of Haslet and Duncanville receiving 14.2" and 14.9", respectively.


Figure 1. Dallas' all-time record snowfall made for an un-inviting swim at this pool in nearby Flower Mound. Image credit: wunderphotographer texasdog.

A few selected snow amounts from the storm, courtesy of the National Weather Service:

...NORTH CAROLINA ...
HARKERS ISLAND 3.2 NE 8.8
HAVELOCK 2.7 S 8.5
BEAUFORT 7.0
NEWPORT 7.0
SEA LEVEL 7.0
OUTLAND 4 S 6.8
WINTERVILLE 3.5 W 6.4
CAPE CARTERET 6.2
BETTIE 6.0
BURGAW 6.0
JACKSONVILLE 6.0
MOREHEAD CITY 6.0
GREENVILLE 5.8

...ALABAMA...
BELLEVILLE 6.0
BRANTLEY 5.0
EVERGREEN 5 N 5.0
THOMASVILLE 5.0
EUFAULA 4 S 4.5
LOTTIE 4.5
MONROEVILLE 0.6 SSW 4.1
ARITON 4.0
PINSON 4.0
RAMER 4.0
TROY 4.0
WARD 4.0

...ARKANSAS...
FOREMAN 4.0
TEXARKANA 1 N 4.0

...FLORIDA...
BERRYDALE 2.0
MUNSON 2.0
JAY 1.0

...GEORGIA...
LUMPKIN 6.0
WASHINGTON 1.9 NE 5.8
LOGANVILLE 4 SSE 5.3
NICHOLSON 4.9 SE 4.8
ATHENS 3.2 NW 4.6
LA GRANGE 10.6 ESE 4.5
WATKINSVILLE 1.6 ENE 4.4
ROCKMART 9.6 SSE 4.3
TALBOTTON 4.0
HAMILTON 5 W 3.5
VILLA RICA 3.5
SENOIA 2 N 3.0
DACULA 2.5
CUTHBERT 2.0
MACON 2.0
ROME 2.0

...LOUISIANA...
SHREVEPORT 9.1 SE 6.1
NATCHITOCHES 0.9 NE 6.0
SHONGALOO 5 N 6.0
SICILY ISLAND 3.3 WNW 6.0
GOLDONNA 8.8 SSW 5.6
MONROE 5.0
PLAIN DEALING 3.3 ESE 5.0
HOMER 1.2 N 3.7
WEST MONROE 6.1 WSW 3.5

...MISSISSIPPI...
DE KALB 8.0
BUDE 6.5
VICKSBURG 6.3
BROOKHAVEN 6.0
NATCHEZ 6.0
PETAL 6.0
BRANDON 5.0
CATAHOULA 5.0
MADISON 5.0
BRANDON 1.9 NE 4.6
MERIDIAN 4.5
MCCALL CREEK 5 W 4.0

...OKLAHOMA...
HAWORTH 4 SW 7.5
IDABEL 8 SE 7.5

...SOUTH CAROLINA...
SUMMERVILLE 3.8 NE 8.2
COLUMBIA 7.3
BAMBERG 7.0
BOWMAN 7.0
EVANS 1 SE 7.0
LEXINGTON 1.6 WNW 7.0
OAK GROVE 1 SE 7.0
OATLAND 8 N 7.0
SMOAKS 7.0
HEMINGWAY 6.8
SANGAREE 6.5
ORANGEBURG 6.0
DARLINGTON 5.0
BLYTHE 4.0
CHARLESTON 3.3
BEAUFORT 3.0

...TEXAS...
DUNCANVILLE 1.7 NNW 14.9
HASLET 14.2
FORT WORTH 12.6
DALLAS 12.5
MANSFIELD 2.6 NNE 12.2
BRIDGEPORT 12.0
ROYSE CITY 12.0
SANGER 1.8 WSW 12.0
MESQUITE 3.3 ESE 11.4
NORTH RICHLAND HILLS 1.9 NE 11.3

As we can see from a plot of the frequency of U.S. snowstorms between 1900 - 2001 (Figure 2), heavy snow events of 6+ inches occur about once every ten years for Dallas, and between once every ten years and once every 100 years for the portions of Louisiana, Mississippi, Alabama, Georgia, South Carolina, and North Carolina that received 6+ inches of snow from this storm.


Figure 2. The annual average number of snowstorms with a 6 inch (15.2 cm) or greater accumulation, from the years 1901 - 2001. A value of 0.1 means an average of one 6+ inch snowstorm every ten years. Image credit: Changnon, S.A., D. Changnon, and T.R. Karl, 2006, Temporal and Spatial Characteristics of Snowstorms in the Contiguous United States, J. Applied Meteorology and Climatology, 45, 8, pp. 1141-1155, DOI: 10.1175/JAM2395.1.

More heavy snowstorms occur in warmer-than-average years
I made this point in yesterday's blog post, but it's worth repeating. Another interesting result from the Changnon et al. (2006) paper of Figure 2 is the relationship between heavy snowstorms and the average winter temperature. For the contiguous U.S. between 1900 - 2001, the authors found that 61% - 80% of all heavy snowstorms of 6+ inches occurred during winters with above normal temperatures. In other words, the old adage, "it's too cold to snow", has some truth to it. The authors also found that 61% - 85% of all heavy snowstorms of 6+ inches occurred during winters that were wetter than average. The authors conclude, "a future with wetter and warmer winters, which is one outcome expected (National Assessment Synthesis Team 2001), will bring more heavy snowstorms of 6+ inches than in 1901 - 2000. The authors found that over the U.S. as a whole, there had been a slight but significant increase in heavy snowstorms of 6+ inches than in 1901 - 2000. So, there is evidence that the average climate of the U.S. over the past 100 years is colder than optimal for heavy snow events to occur. If the climate continues to warm, we should expect an increase in heavy snow events for a few decades, until the climate grows so warm that we pass the point where winter temperatures are at the optimum for heavy snow events. However, a study by Houston and Changnon (2009) on the most severe types of snowstorms--the "top ten" heaviest snows on record for each of 121 major U.S. cities--shows no upward or downward trend in the very heaviest snowstorms for the contiguous U.S. between 1948 - 2001.

A new snowstorm for the mid-Atlantic and New York City on Monday
The extreme amounts of snow on the ground in the Mid-Atlantic thanks to back-to-back blizzards over the past week will get a fresh layer on top Monday night, when a new snowstorm will probably dump another 3 - 6 inches of snow on Washington D.C., Baltimore, and Philadelphia. The new storm is called an "Alberta Clipper", due to its fast motion and genesis location in Canada's Alberta Province. These storms are relatively dry and tend to bring lighter, fluffier snow. Once the Clipper moves out over the Atlantic off the coast of Maryland, it will pick up some Atlantic moisture and bring some heavier snows to the New York City region, potentially 6 - 10 inches.

Media coverage by the Washington Post
I did a phone-in press call with 20 media outlets on Thursday, to discuss how record snowstorms do not imply that global warming is not occurring. Participating on the call with me was Dr. Joe Romm, who blogs on climate-related issues for climateprogress.org. The audio is posted there if you want to listen.

The Washington Post highlighted a portion of the call where I said, "there's a huge amount of natural variability in the climate system", not enough years of measurements to know exactly what's going on, and "Unfortunately we don't have that data so we are forced to make decisions based on inadequate data." The article said that my statements shot down the statement by Joe Romm that "the overwhelming weight of the scientific literature" points to human-caused warming and that doubters "don't understand the science." Let me clarify that there will always be considerable uncertainty in our understanding of a chaotic system like the atmosphere. We should not demand certainty where it cannot exist, always using uncertainty as an excuse for taking no action. Keep in mind that the uncertainty goes both ways--climate change could be far worse than the IPCC is predicting, and it would be wise to buy an intelligent amount of insurance to protect ourselves. I agree with Dr. Romm's statement, and the official Statement on Climate Change from the American Meteorological Society, "Despite the uncertainties...there is adequate evidence from observations and interpretations of climate simulations to conclude that the atmosphere, ocean, and land surface are warming; that humans have significantly contributed to this change; and that further climate change will continue to have important impacts on human societies, on economies, on ecosystems, and on wildlife through the 21st century and beyond." The official statement from the UK Royal Society and UK Met Office is also one I agree with, "The 2007 IPCC Assessment, the most comprehensive and respected analysis of climate change to date, states clearly that without substantial global reductions of greenhouse gas emissions we can likely expect a world of increasing droughts, floods and species loss, of rising seas and displaced human populations. However even since the 2007 IPCC Assessment the evidence for dangerous, long-term and potentially irreversible climate change has strengthened. The scientific evidence which underpins calls for action at Copenhagen is very strong. Without coordinated international action on greenhouse gas emissions, the impacts on climate and civilization could be severe.".

Next post
Looks like the winter onslaught will slow down for a day, so I'll be back Monday with a new post.

Jeff Masters

Winter Weather

A rare Deep South snow event breaks Dallas' all-time snowfall record

By: JeffMasters, 3:55 PM GMT on February 12, 2010

A rare Deep South heavy snow event is in full swing today, thanks to a powerful 1000 mb extratropical storm centered just south of Alabama. The storm clobbered Dallas with 11.2" of snow yesterday, the heaviest snow on record for the Dallas-Fort Worth Airport. Dallas' previous record was 7.4", set on January 15 - 16, 1964. The 14.4" of snow that has now fallen on Dallas this winter eclipses the previous record seasonal snowfall for the city--14.1" during the winter of 1977 - 1978. Yesterday's snowstorm dumped over a foot of snow along a narrow region just north of Dallas and Fort Worth, with the town of Haslet receiving 14.2".


Figure 1. The Deep South snow event of February, 12, 2010 in a visible satellite image taken at 9 am EST. Image credit: NASA GOES project.

As the storm races eastwards across the Gulf today, a wide area of snowfall in excess of four inches will affect Arkansas, Louisiana, Mississippi, and Alabama, with lesser amounts in South Carolina, North Carolina, and the extreme northwestern corner of the Florida Panhandle. As of 7am this morning, here are some selected snow amounts reported by National Weather Service:

...ALABAMA...
CUBA 1.5
THOMASVILLE 1.0

...ARKANSAS...
FOREMAN 4.0
TEXARKANA 1 N 4.0

...LOUISIANA...
NATCHITOCHES 6.0
SHONGALOO 5 N 6.0
SHREVEPORT 5.4
MONROE 5.0
NATCHITOCHES 4.0

...MISSISSIPPI...
DE KALB 8.0
CATAHOULA 5.0
VICKSBURG 5.0
RAYVILLE 4.2
BROOKHAVEN 4.0
MCCALL CREEK 5 W 4.0
SICILY ISLAND 4.0
JACKSON 3.2

...OKLAHOMA...
HAWORTH 4 SW 7.5
IDABEL 8 SE 7.5
RATTAN 13 E 4.5

...TEXAS...
HASLET 14.2
FORT WORTH 12.6
DALLAS 12.5
BRIDGEPORT 12.0
ROYSE CITY 12.0
POINT 3.7 ESE 11.0
EAGLE MOUNTAIN 10.5
ENNIS 10.3
FRISCO 1.9 N 10.3
JACKSBORO 6.2 SW 10.0
LINDALE 10.0
NORTH RICHLAND HILLS 10.0
COTTONDALE 9.5
OAK CLIFF 9.5
PRINCETON 3 N 9.5
FORT WORTH 14 N 9.0
ARLINGTON 8.0

As we can see from a plot of the frequency of U.S. snowstorms between 1900 - 2001 (Figure 2), heavy snow events of 6+ inches occur about once every ten years for Dallas, and between once every ten years and once every 100 years for the portions of Louisiana, Mississippi, and Alabama that may end up getting 6+ inches from this storm.


Figure 2. The annual average number of snowstorms with a 6 inch (15.2 cm) or greater accumulation, from the years 1901 - 2001. A value of 0.1 means an average of one 6+ inch snowstorm every ten years. Image credit: Changnon, S.A., D. Changnon, and T.R. Karl, 2006, Temporal and Spatial Characteristics of Snowstorms in the Contiguous United States, J. Applied Meteorology and Climatology, 45, 8, pp. 1141-1155, DOI: 10.1175/JAM2395.1.

More heavy snowstorms occur in warmer-than-average years
Another interesting result from the Changnon et al. (2006) paper (Figure 2) is the relationship between heavy snowstorms and the average winter temperature. For the contiguous U.S. between 1900 - 2001, the authors found that 61% - 80% of all heavy snowstorms of 6+ inches occurred during winters with above normal temperatures. In other words, the old adage, "it's too cold to snow", has some truth to it. The authors also found that 61% - 85% of all heavy snowstorms of 6+ inches occurred during winters that were wetter than average. The authors conclude, "a future with wetter and warmer winters, which is one outcome expected (National Assessment Synthesis Team 2001), will bring more heavy snowstorms of 6+ inches than in 1901 - 2000. The authors found that over the U.S. as a whole, there had been a slight but significant increase in heavy snowstorms of 6+ inches between 1901 - 2000. However, a separate paper by Houston and Changnon (2009), "Characteristics of the top ten snowstorms at First-Order Stations in the U.S.", found that there was no upward or downward trend in the very heaviest snowstorms for the contiguous U.S. between 1948 - 2001, as evaluated by looking at the top ten snowstorms for 121 major cities.

More snow headed for the mid-Atlantic next week
The extreme amounts of snow on the ground in the Mid-Atlantic from back-to-back blizzards over the past week will get some more company on Monday night, when a new snowstorm will hit the region. I'm thinking that the new storm will drop another 2 - 6 inches of snow on the Baltimore-D.C.-Philadelphia region. The computer forecast models have not yet come into agreement on where Monday's storm will hit, or how much moisture it will be able to tap into, so there is still high uncertainty over how much snow will fall.

A historical precedent for "Snowmageddon": the "Great Snow" of 1717
I've commented several times this week that there is no precedent in the historical record, going back to the late 1800s, to the incredible snow blitz the Mid-Atlantic has endured. Well, it turns out there is a comparable winter, at least for Philadelphia, if one goes back in time nearly 300 years. According to Chris Burt, author of the excellent book, Extreme Weather, in 1717 four storms between February 27 and March 9 dropped a total of 3 - 5 feet of snow from Philadelphia to Boston. Snow drifts as much as 25' deep occurred in the Boston area. An account of the 1717 event was one of the first journal entries of the Massachusetts Historical Society by Cotton Mather. Chris told me he wasn't aware of any comparable events affecting Washington D.C. or Baltimore, however. Chris will be joining wunderground this April as a featured blogger, and I greatly look forward to having him put our modern weather records into historical context.

Next post
I'll probably do a short post on Saturday.

Jeff Masters

Winter Weather

Mid-Atlantic sets all-time snow records

By: JeffMasters, 12:15 PM GMT on February 11, 2010

The second ferocious blizzard in a week to pound the Mid-Atlantic continues to intensify, but has now moved out to sea away from the coast. That's a very good thing, because with a central pressure of 969 mb, the storm is as intense as a Category 1 hurricane. The blizzard brought wind gusts as high as 51 mph at Massachusetts' Nantucket Island last night. The snow has pretty much ended over the Northeastern U.S., but the mighty blizzard dumped 1 - 2 feet of snow over much of the Mid-Atlantic and Northeast, with a peak snowfall of 27.5" recorded at Ortanna, Pennsylvania. When combined with the 1 - 2 feet of snow still on the ground from last weekend's blizzard, the snow depths in the Mid-Atlantic are reaching ridiculous proportions. This morning, Baltimore reported 35" of snow on the ground, which would break their previous all-time record of 30" on snow on the ground, set on February 13, 1899. The 19.8" that fell on Baltimore from the blizzard was that city's 10th greatest snowfall on record. Philadelphia's 15.8" was its ninth greatest snowfall. The winter of 2009 - 2010 now has three spots on the top ten all-time heaviest snowfall list for those cities. Record keeping began in the late 1800s, and I'm not aware of any major city in the U.S. that has that many record snowfalls in one winter. If there is, I want to hear about it! Washington D.C.'s 10.8" snowfall from the storm missed making its top ten list of heaviest snows, so that city has only two storms from the winter of 2009 - 2010 on the list. The snow blitz that the Mid-Atlantic has endured with the three record-setting Nor'easters of the 2009 - 2010 is truly a rare event that has no parallel in the historic record.


Figure 1. The Nor'easter of February, 11, 2010 in a infrared satellite image taken at 9:40 pm EST. Image credit: NASA GOES project.

Top 10 snowstorms on record for Philadelphia:

1. 30.7", Jan 7-8, 1996
2. 28.5", Feb 5-6, 2010 (Snowmageddon)
3. 23.2", Dec 19-20, 2009 (Snowpocalypse)
4. 21.3", Feb 11-12, 1983
5. 21.0", Dec 25-26, 1909
6. 19.4", Apr 3-4, 1915
7. 18.9", Feb 12-14, 1899
8. 16.7", Jan 22-24, 1935
9. 15.8", Feb 10-11, 2010
10. 15.1", Feb 28-Mar 1, 1941

The top 10 snowstorms on record for Baltimore:

1. 28.2", Feb 15-18, 2003
2. 26.5", Jan 27-29, 1922
3. 24.8", Feb 5-6, 2010 (Snowmageddon)
4. 22.8", Feb 11-12, 1983
5. 22.5", Jan 7-8, 1996
6. 22.0", Mar 29-30, 1942
7. 21.4", Feb 11-14, 1899
8. 21.0", Dec 19-20, 2009 (Snowpocalypse)
9. 20.0", Feb 18-19, 1979
10. 19.5", Feb 10-11, 2010

The top 10 snowstorms on record for Washington, D.C.:

1. 28.0", Jan 27-28, 1922
2. 20.5", Feb 11-13, 1899
3. 18.7", Feb 18-19, 1979
4. 17.8" Feb 5-6, 2010 (Snowmageddon)
5. 17.1", Jan 6-8, 1996
6. 16.7", Feb 15-18, 2003
7. 16.6", Feb 11-12, 1983
8. 16.4", Dec 19-20, 2009 (Snowpocalypse)
9. 14.4", Feb 15-16, 1958
10. 14.4", Feb 7, 1936

Snowiest winter on record for Baltimore, Washington D.C., Philadelphia, Atlantic City, and Wilmington
The snow from this latest blizzard have pushed snow totals for the 2009 - 2010 winter season to a new record for Baltimore, Washington D.C., Wilmington, Philadelphia, and Atlantic City. As of midnight last night, here were the snowfall numbers so far for the 2009 - 2010 winter, and the records they have broken:

Baltimore, MD, 79.9". Old record: 62.5", winter of 1995 - 1996.
Washington D.C. National Airport, 55.9". Old record: 54.4", winter of 1898 - 1899.
Washington Dulles Airport, VA, 75.0". Old record: 61.9", winter of 1995 - 1996.
Wilmington, DE, 66.7". Old record: 55.9", winter of 1995 - 1996.
Philadelphia, PA, 71.6". Old record: 65.5", winter of 1995 - 1996.
Atlantic City, NJ, 49.9". Current record: 46.9", winter of 1966 - 1967.

For comparison, the average snowfall amounts for a season for these cities ranges from 16 - 22". This winter's snowfall amounts are similar to what Anchorage, Alaska and Portland Maine typically receive (about 70"). All this comes with the end of winter still more than a month away--and more snow is likely to fall yet this winter. The latest runs of the GFS and ECMWF models show yet another Nor'easter hitting the D.C./Baltimore/Philadelphia region next Monday. However, next Monday's storm is likely to be much weaker than the last two Nor'easters, with perhaps 2 - 8 inches of snow falling. It is too early to be confident of this prediction, though, and it is possible that the storm will miss.

The extreme amounts of snow on the ground in the Mid-Atlantic will melt only slowly over the coming week, as temperatures are expected to climb only into the low to mid-thirties. That is a good thing, because a sudden thaw could create significant flooding problems. The latest long-range forecast from the GFS model predicts continued below-average temperatures for the mid-Atlantic region for at least the next week, with a possible significant thaw occurring the last week of February.

A new winter storm takes aim at the Deep South
A powerful and fast-moving low pressure system is developing over the Gulf of Mexico today, and will pull in a significant amount of Gulf moisture over the very cold air mass in place over the Deep South today and Friday. A band of moderate snow will develop over Louisiana, Mississippi, and Alabama, bringing 4 - 6" of snow to the southern portions of those states. Florida's Panhandle will see mostly rain, but some snow is expected to mix in, with accumulations around an inch possible in the extreme northwest Panhandle near the Alabama border, away from shore. Among the major cities likely to get 2+ inches of snow are Mobile, Jackson, and Montgomery. The record heaviest snowfalls for those cities are 6", 11.7", and 11", respectively.

Snow avalanches in Afghanistan kill 172
The U.S. isn't the only part of the world with heavy snow problems this winter. Heavy snow in Afghanistan triggered avalanches Monday that killed at least 172 people traveling along the road over 12,700 foot high Salang Pass through the Hindu-Kush Mountains, according to media reports. The death toll makes this avalanche one of the ten deadliest in world history. The ten deadliest world avalanche disasters, as compiled using Scientific American and the book, Natural Disasters and How We Cope, are:

1) 218 B.C. Avalanches decimate Hannibal's army as it crosses the Alps with elephants. Twenty thousand soldiers and many elephants are lost.

2) 1970. The Huascaran Mountain, Peru avalanche of May 31, 1970. A magnitude 8.0 earthquake caused a huge chunk of snow-covered glacier to collapse and roar down the mountain, killing up to 20,000 people.

3) 1916. A series of avalanches during a WW I battle kills at least 10,000 Austrian and Italian soldiers over a 48-hour period. Many of these avalanches were triggered by artillery fire.

4) 1962. Huascaran Mountain, Peru avalanche of January 10, 1962. Avalanches from heavy snows killed up to 4,000.

5) 1618. Plurs, Switzerland: the Rodi avalanche buries the town of Plurs, claiming 2,427 victims. Note: since this avalanche occurred in August, it is likely that is was actually a rock avalanche, and therefore does not belong on this list. Thanks go to Randy Head for pointing out this error that has made it into many Internet locations.

6) 1951. A January avalanche in the Alps' The "Winter of Terror" kills 275.

7) 1991. Bingol, Turkey: an avalanche hits several towns, killing 255 people.

8) 1954. Vovarlberg disaster of January 12, 1954, killed 225 in the Austrian Alps. Nine hours later, a second avalanche killed 115 survivors and rescue workers.

9) 1979. Lahaul Valley, India. A series of avalanches bury the valley, leaving at least 200 victims .

10) 2010. Salang Pass, Afghanistan avalanche kills 166.

The worst avalanche in U.S. history is the Wellington, Washington avalanche of March 1, 1910, which killed 96 people on a train and at a train station.

Jeff Masters

Winter Weather

Second ferocious Nor'easter in a week pounds U.S. East Coast

By: JeffMasters, 2:57 PM GMT on February 10, 2010

A ferocious blizzard likely to be even more intense that last weekend's crippling Mid-Atlantic "Snowmageddon" snowstorm is rapidly intensifying off the Northeast U.S. coast, just south of New York City today. Blizzard conditions with heavy snow, high winds, and near zero visibility have hit or are expected to hit portions of West Virginia, Virginia, Maryland, Washington D.C., Pennsylvania, Delaware, New Jersey, and New York, including the cities of New York, Newark, Wilmington, Atlantic City, Philadelphia, Baltimore, and Washington D.C. The storm responsible tracked across the center of the country yesterday, leaving a wide swath of snow amounts of 4 - 16" across Texas, Tennessee, South Dakota, Oklahoma, Mississippi, Missouri, Minnesota, Kansas, Iowa, Arkansas, Alabama, Wisconsin, Illinois, Michigan, Ohio, Indiana, and Kentucky. The storm is now centered over Lake Erie, with a new 989 mb low pressure center developing off the coast of Delaware. This new low is predicted to "bomb" into a mighty Nor'easter with a central pressure below 970 mb, the kind of pressure typically found in a Category 1 hurricane. This will bring strong winds, gusting over 40 mph, to a large portion of the Mid-Atlantic and Northeast U.S. today, causing a larger region of blizzard conditions with blowing and drifting snow than was experienced during last weekend's "Snowmageddon" Nor'easter. Fortunately, today's Nor'easter will be far enough from the coast during its peak intensity that coastal flooding from storm surges will not be a concern. In addition, today's blizzard has a lower moisture content than "Snowmageddon", and the snowfall totals will not be as great. The storm has also wrapped in some warmer air from the south, resulting in a change-over to freezing rain and sleet near the coast this morning, which will limit accumulations. Nevertheless, most of the Mid-Atlantic that received two feet of snow from "Snowmageddon" last weekend will receive another foot of snow today, and there is a significant risk of roof collapses from the weight of all this snow.


Figure 1. The Nor'easter of February, 11, 2010 in a visible satellite image taken at 9:01 am EST. Image credit: NASA GOES project.

Snowiest winter on record for Baltimore, Wilmington, and Dulles
The snow from this latest blizzard have pushed snow totals for the 2009 - 2010 winter season to a new record for Baltimore, Wilmington, and Dulles Airport, and will likely set a new seasonal snowfall record in Philadelphia, Atlantic City, and Washington National Airport later today. As of midnight last night, here are the snowfall numbers so far for the 2009 - 2010 winter, and the records they have broken:

Baltimore, MD, 64.4". Old record: 62.5", winter of 1995 - 1996.
Washington Dulles Airport, VA, 65.7". Old record: 61.9", winter of 1995 - 1996.
Wilmington, DE, 59.5". Old record: 55.9", winter of 1995 - 1996.

Cities close to breaking their seasonal snowfall record:

Philadelphia, PA, 62.3". Current record: 65.5", winter of 1995 - 1996.
Washington D.C. National Airport, 48.8". Current record: 54.4", winter of 1898 - 1899.
Atlantic City, NJ, 45.5". Current record: 46.9", winter of 1966 - 1967.

All this comes with the end of winter still more than a month away. The latest runs of the GFS and ECMWF models show yet another Nor'easter hitting the D.C./Baltimore/Philadelphia region next Monday. However, next Monday's storm is likely to be much weaker than the last two Nor'easters, with perhaps 4 - 8 inches of snow falling. It is too early to be confident of this prediction, and a Mid-Atlantic snowstorm may not materialize at all on Monday--or the storm could grow stronger than currently forecast, with more than a foot of snow falling.

Heavy snow events--a contradiction to global warming theory?
As I discussed in my previous post, record-breaking snowstorms are not an indication that global warming is not occurring. In fact, we can expect there may be more heavy snowstorms in regions where it is cold enough to snow, due to the extra moisture global warming has added to the atmosphere--an extra 4% since 1970. Snow is not the same as cold, and we have to look at global temperatures, not snowfall, to evaluate whether global warming is occurring. Heavy snow can act to bring down global temperatures, as occurred in December 2009, when the Northern Hemisphere experienced its second greatest snow extent on record (only 1985 saw greater December snow cover since reliable snow records began in 1967). Global average land temperatures, as a result, were just 31st warmest on record, even though global ocean temperatures were the 2nd warmest on record. It will be interesting to see what global temperatures did in January, when the statistics are released next week. The global temperature of the lower atmosphere as measured by satellites was the warmest on record in January, and by a considerable margin. I'll discuss this finding in more detail once the blizzard is over. It's also of interest to note that December temperatures in the U.S. were the 18th coldest in the historical record, but January temperatures were 0.3°F above average, according to the National Climatic Data Center. As a whole, it's been a colder than average winter in the U.S., but not greatly so. However, December snow cover was the greatest on record in the contiguous U.S., and January's ranked sixth. Snow cover records go back 44 years, to 1967.

Portlight continues relief efforts in Haiti
Portlight.org disaster-relief continues to be more effective than some of the traditional large aid agencies in getting much-needed crutches, walkers, and other medical supplies to disabled victims of the Haitian earthquake. So, please visit the Portlight.org blog to learn more and to donate. Floodman's blog has the latest info on Portlight's plan for Haitian relief. A few highlights from his blog:

The latest shipment arrived at Quisqueya University in Port-au-Prince on Friday morning; the shipment was unloaded and a portion of the supplies distributed to the St Nicholas Hospital in Sainte-Marc north of Port-au-Prince. This shipment included wheelchairs, crutches and canes in addition to clinical supplies. It was a busy day at Quisqueya; Susan Eitel, representative of USAID met with Richard this morning and Dr. Amy Nguyen of ACTS World Relief took delivery of DME at the Quisqueya campus.

We have several additional shipments queued up for transport, one of which shipped on Saturday; these shipments include the remainder of the donation from H&H Wholesalers. We are hoping to have another shipment out in the next few days.

We are concentrating on distribution for the next few days as storage is currently at a premium at Quisqueya; we are also concentrating on expanding our storage capabilities to allow for larger shipments to be handled, allowing us to help a larger segment of the disabled community.



Figure 2. The Portlight Relief Team unloads crutches shipped from Portlight's warehouse in Atlanta to a staging area at University Quisqeya, Port-au-Prince, Haiti. The relief team consists of ten Haitians being coordinated by Haitian-American Richard Lumarque, Portlight's on-site coordinator in Haiti. The relief team has been working full-time over the past week doing aid work.

Next post
I'll have a new post on Thursday.

Jeff Masters

Winter Weather

Heavy snowfall in a warming world

By: JeffMasters, 3:29 PM GMT on February 08, 2010

A major new winter storm is headed east over the U.S. today, and threatens to dump a foot or more of snow on Philadelphia, New York City, and surrounding regions Tuesday and Wednesday. Philadelphia is still digging out from its second top-ten snowstorm of recorded history to hit the city this winter, and the streets are going to begin looking like canyons if this week's snowstorm adds a significant amount of snow to the incredible 28.5" that fell during "Snowmageddon" last Friday and Saturday. Philadelphia has had two snowstorms exceeding 23" this winter. According to the National Climatic Data Center, the return period for a 22+ inch snow storm is once every 100 years--and we've had two 100-year snow storms in Philadelphia this winter. It is true that if the winter pattern of jet stream location, sea surface temperatures, etc, are suitable for a 100-year storm to form, that will increase the chances for a second such storm to occur that same year, and thus the odds have having two 100-year storms the same year are not 1 in 10,000. Still, the two huge snowstorms this winter in the Mid-Atlantic are definitely a very rare event one should see only once every few hundred years, and is something that has not occurred since modern records began in 1870. The situation is similar for Baltimore and Washington D.C. According to the National Climatic Data Center, the expected return period in the Washington D.C./Baltimore region for snowstorms with more than 16 inches of snow is about once every 25 years. This one-two punch of two major Nor'easters in one winter with 16+ inches of snow is unprecedented in the historical record for the region, which goes back to the late 1800s.


Figure 1. Car buried in Virginia by "Snowmageddon" on February 8, 2010. Image credit: wunderphotographer Brabus Cave.

Top 9 snowstorms on record for Philadelphia:

1. 30.7", Jan 7-8, 1996
2. 28.5", Feb 5-6, 2010 (Snowmageddon)
3. 23.2", Dec 19-20, 2009 (Snowpocalypse)
4. 21.3", Feb 11-12, 1983
5. 21.0", Dec 25-26, 1909
6. 19.4", Apr 3-4, 1915
7. 18.9", Feb 12-14, 1899
8. 16.7", Jan 22-24, 1935
9. 15.1", Feb 28-Mar 1, 1941

The top 10 snowstorms on record for Baltimore:

1. 28.2", Feb 15-18, 2003
2. 26.5", Jan 27-29, 1922
3. 24.8", Feb 5-6, 2010 (Snowmageddon)
4. 22.8", Feb 11-12, 1983
5. 22.5", Jan 7-8, 1996
6. 22.0", Mar 29-30, 1942
7. 21.4", Feb 11-14, 1899
8. 21.0", Dec 19-20, 2009 (Snowpocalypse)
9. 20.0", Feb 18-19, 1979
10. 16.0", Mar 15-18, 1892

The top 10 snowstorms on record for Washington, D.C.:

1. 28.0", Jan 27-28, 1922
2. 20.5", Feb 11-13, 1899
3. 18.7", Feb 18-19, 1979
4. 17.8" Feb 5-6, 2010 (Snowmageddon)
5. 17.1", Jan 6-8, 1996
6. 16.7", Feb 15-18, 2003
7. 16.6", Feb 11-12, 1983
8. 16.4", Dec 19-20, 2009 (Snowpocalypse)
9. 14.4", Feb 15-16, 1958
10. 14.4", Feb 7, 1936

Heavy snow events--a contradiction to global warming theory?
Global warming skeptics regularly have a field day whenever a record snow storm pounds the U.S., claiming that such events are inconsistent with a globe that is warming. If the globe is warming, there should, on average, be fewer days when it snows, and thus fewer snow storms. However, it is possible that if climate change is simultaneously causing an increase in ratio of snowstorms with very heavy snow to storms with ordinary amounts of snow, we could actually see an increase in very heavy snowstorms in some portions of the world. There is evidence that this is happening for winter storms in the Northeast U.S.--the mighty Nor'easters like the "Snowmageddon" storm of February 5-6 and "Snowpocalypse" of December 19, 2009. Let's take a look at the evidence. There are two requirements for a record snow storm:

1) A near-record amount of moisture in the air (or a very slow moving storm).
2) Temperatures cold enough for snow.

It's not hard at all to get temperatures cold enough for snow in a world experiencing global warming. According to the 2007 Intergovernmental Panel on Climate Change (IPCC) report, the globe warmed 0.74°C (1.3°F) over the past 100 years. There will still be colder than average winters in a world that is experiencing warming, with plenty of opportunities for snow. The more difficult ingredient for producing a record snowstorm is the requirement of near-record levels of moisture. Global warming theory predicts that global precipitation will increase, and that heavy precipitation events--the ones most likely to cause flash flooding--will also increase. This occurs because as the climate warms, evaporation of moisture from the oceans increases, resulting in more water vapor in the air. According to the 2007 Intergovernmental Panel on Climate Change (IPCC) report, water vapor in the global atmosphere has increased by about 5% over the 20th century, and 4% since 1970. This extra moisture in the air will tend to produce heavier snowstorms, assuming it is cold enough to snow. Groisman et al. (2004) found a 14% increase in heavy (top 5%) and 20% increase in very heavy (top 1%) precipitation events in the U.S. over the past 100 years, though mainly in spring and summer. However, the authors did find a significant increase in winter heavy precipitation events have occurred in the Northeast U.S. This was echoed by Changnon et al. (2006), who found, "The temporal distribution of snowstorms exhibited wide fluctuations during 1901-2000, with downward 100-yr trends in the lower Midwest, South, and West Coast. Upward trends occurred in the upper Midwest, East, and Northeast, and the national trend for 1901-2000 was upward, corresponding to trends in strong cyclonic activity."

The strongest cold-season storms are likely to become stronger and more frequent for the U.S.
The U.S. Global Change Research Program (USGCRP) began as a presidential initiative in 1989 and was mandated by Congress in the Global Change Research Act of 1990 (P.L. 101-606), which called for "a comprehensive and integrated United States research program which will assist the Nation and the world to understand, assess, predict, and respond to human-induced and natural processes of global change." This program has put out some excellent peer-reviewed science on climate change that, in my view, is as authoritative as the U.N.-sponsored Intergovernmental Panel on Climate Change (IPCC) reports. In 2009, the USGCRP put out its excellent U.S. Climate Impacts Report, summarizing the observed and forecast impacts of climate change on the U.S. The report's main conclusion about cold season storms was " Cold-season storm tracks are shifting northward and the strongest storms are likely to become stronger and more frequent".

The report's more detailed analysis: "Large-scale storm systems are the dominant weather phenomenon during the cold season in the United States. Although the analysis of these storms is complicated by a relatively short length of most observational records and by the highly variable nature of strong storms, some clear patterns have emerged (Kunkel et al., 2008).

Storm tracks have shifted northward over the last 50 years as evidenced by a decrease in the frequency of storms in mid-latitude areas of the Northern Hemisphere, while high-latitude activity has increased. There is also evidence of an increase in the intensity of storms in both the mid- and high-latitude areas of the Northern Hemisphere, with greater confidence in the increases occurring in high latitudes (Kunkel et al., 2008). The northward shift is projected to continue, and strong cold season storms are likely to become stronger and more frequent, with greater wind speeds and more extreme wave heights".
The study also noted that we should expect an increase in lake-effect snowstorms over the next few decades. Lake-effect snow is produced by the strong flow of cold air across large areas of relatively warmer ice-free water. The report says, "As the climate has warmed, ice coverage on the Great Lakes has fallen. The maximum seasonal coverage of Great Lakes ice decreased at a rate of 8.4 percent per decade from 1973 through 2008, amounting to a roughly 30 percent decrease in ice coverage. This has created conditions conducive to greater evaporation of moisture and thus heavier snowstorms. Among recent extreme lake-effect snow events was a February 2007 10-day storm total of over 10 feet of snow in western New York state. Climate models suggest that lake-effect snowfalls are likely to increase over the next few decades. In the longer term, lake-effect snows are likely to decrease as temperatures continue to rise, with the precipitation then falling as rain".


Figure 2. The annual average number of snowstorms with a 6 inch (15.2 cm) or greater accumulation, from the years 1901 - 2001. A value of 0.1 means an average of one 6+ inch snowstorm every ten years. Image credit: Changnon, S.A., D. Changnon, and T.R. Karl, 2006, Temporal and Spatial Characteristics of Snowstorms in the Contiguous United States, J. Applied Meteorology and Climatology, 45, 8, pp. 1141-1155, DOI: 10.1175/JAM2395.1.

More heavy snowstorms occur in warmer-than-average years
Another interesting result from the Changnon et al. (2006) paper (Figure 2) is the relationship between heavy snowstorms and the average winter temperature. For the contiguous U.S. between 1900 - 2001, the authors found that 61% - 80% of all heavy snowstorms of 6+ inches occurred during winters with above normal temperatures. In other words, the old adage, "it's too cold to snow", has some truth to it. The authors also found that 61% - 85% of all heavy snowstorms of 6+ inches occurred during winters that were wetter than average. The authors conclude, "a future with wetter and warmer winters, which is one outcome expected (National Assessment Synthesis Team 2001), will bring more heavy snowstorms of 6+ inches than in 1901 - 2000. The authors found that over the U.S. as a whole, there had been a slight but significant increase in heavy snowstorms of 6+ inches between 1901 - 2000. However, a separate paper by Houston and Changnon (2009), "Characteristics of the top ten snowstorms at First-Order Stations in the U.S.", found that there was no upward or downward trend in the very heaviest snowstorms for the contiguous U.S. between 1948 - 2001, as evaluated by looking at the top ten snowstorms for 121 major cities.

Commentary
One can "load the dice" in favor of events that used to be rare--or unheard of--if the climate is changing to a new state. It is quite possible that nature's weather dice have been loaded in favor of more intense Nor'easters for the U.S. Mid-Atlantic and Northeast, thanks to the higher levels of moisture present in the air due to warmer global temperatures. It's worth mentioning that heavy snow storms should be getting increasingly rare for the extreme southern portion of the U.S. in coming decades. There's almost always high amounts of moisture available for a potential heavy snow in the South--just not enough cold air. With freezing temperatures expected to decrease and the jet stream and associated storm track expected to move northward, the extreme southern portion of the U.S. should see a reduction in both heavy and ordinary snow storms in the coming decades.

The CapitalClimate blog has a nice perspective on "Snowmageddon", and Joe Romm of climateprogress.org has some interesting things to say about snowstorms in a warming climate.

References
Changnon, S.A., D. Changnon, and T.R. Karl, 2006, , "Temporal and Spatial Characteristics of Snowstorms in the Contiguous United States", J. Appl. Meteor. Climatol., 45, 1141.1155.

Groisman, P.Y., R.W. Knight, T.R. Karl, D.R. Easterling, B. Sun, and J.H. Lawrimore, 2004, "Contemporary Changes of the Hydrological Cycle over the Contiguous United States: Trends Derived from In Situ Observations," J. Hydrometeor., 5, 64-85.

Kunkel, K.E., P.D. Bromirski, H.E. Brooks, T. Cavazos, A.V. Douglas, D.R. Easterling, K.A. Emanuel, P.Ya. Groisman, G.J. Holland, T.R. Knutson, J.P. Kossin, P.D. Komar, D.H. Levinson, and R.L. Smith, 2008: Observed changes in weather and climate extremes. In: Weather and Climate Extremes in a Changing Climate: Regions of Focus: North America, Hawaii, Caribbean, and U.S. Pacific Islands [Karl, T.R., G.A. Meehl, C.D. Miller, S.J. Hassol, A.M. Waple, and W.L. Murray (eds.)]. Synthesis and Assessment Product 3.3. U.S. Climate Change Science Program, Washington, DC, pp. 35-80.

Congratulations, New Orleans!
Congratulations to everyone in New Orleans, for the Saints' Super Bowl victory! It's great to the see the city celebrating after enduring so many years of hardship in the wake of Hurricane Katrina.

Jeff Masters

Winter Weather

Snowmageddon storm clobbers the Mid-Atlantic with 2 - 3 feet of snow

By: JeffMasters, 11:08 PM GMT on February 06, 2010

It's a very white world in the Mid-Atlantic today, where the historic blizzard of 2010 has buried residents under a record-breaking two to three feet of snow. The storm, which President Obama referred to as "Snowmageddon" in a speech before the Democratic National Committee winter meeting, set the all-time record for heaviest snowfall in Delaware history, thanks to the 26.5" that fell in Wilmington (old state record: 25" in the President's Day storm of 2003). "Snowmageddon" dumped the second heaviest at Philadelphia 28.5"), second heaviest at Atlantic City (18.2"), third heaviest at Baltimore (24.8"), and the 4th heaviest at Washington D.C. (17.8"). Several locations in Maryland have seen over three feet of snow, with the northern Washington D.C. suburb of Colesville receiving 40", and the southern Baltimore suburb of Elkridge receiving 38.3". While the blizzard was not an exceptionally strong storm--the central pressure was a rather unimpressive 986 mb at the height of the blizzard, at 9am EST Saturday--it was an exceptionally wet storm. The melted equivalent precipitation for the blizzard exceeded three inches along its core snow belt. That's an phenomenal amount of moisture for a winter storm. The blizzard formed a very unstable region aloft where thunderstorms were able to build, and there were many reports of thundersnow during the height of the storm. These embedded thunderstorms were able to generate very heavy snow bursts of 2 - 3 inches per hour.

A new storm expected to affect the area Tuesday may add to the immense pile of snow on the ground, though the precipitation may partially fall as rain. With only a slow warm up in store for the mid-Atlantic over the next ten days, the snow will stick around for a while. This is a good thing, since a sudden thaw or heavy rain event could generate considerable flooding, if the three inches of precipitation locked in the snow is suddenly released.

Today's blizzard is the second major snowstorm of 16+ inches to affect the Washington D.C./Baltimore region this winter--the other being the 16.4" storm of December 19 - 20. According to the National Climatic Data Center, the expected return period in the Washington D.C./Baltimore region for snowstorms with more than 16 inches of snow is about once every 25 years. Thus, a one-two punch of two major Mid-Atlantic Nor'easters with 16+ inches of snow in one winter is something that should happen only once every 625 years. Such an event has not happened since the beginning of the historical record in 1870. The numbers are even more impressive for Philadelphia, which has had two snowstorms exceeding 23" this winter. According to the National Climatic Data Center, the return period for a 22+ inch snow storm is once every 100 years--and we've had two 100-year snow storms in Philadelphia this winter. That should happen only once every 10,000 years, in today's climate. Of course, the last ice age was just ending around 12,000 years ago, so this probability number has to be viewed with a some skepticism. Still, the two huge snowstorms this winter in the Mid-Atlantic are definitely a very rare event one should see only once every few hundred years.


Figure 1. "Snowmageddon", the Nor'easter of February 5 - 6, just off the Mid-Atlantic coast, at 12:01 pm EST Saturday 2/6/10. Image credit: NASA GOES project.

The top 10 snowstorms on record for Baltimore:

1. 28.2", Feb 15-18, 2003
2. 26.5", Jan 27-29, 1922
3. 24.8", Feb 5-6, 2010
4. 22.8", Feb 11-12, 1983
5. 22.5", Jan 7-8, 1996
6. 22.0", Mar 29-30, 1942
7. 21.4", Feb 11-14, 1899
8. 21.0", Dec 19-20, 2009
9. 20.0", Feb 18-19, 1979
10. 16.0", Mar 15-18, 1892

The top 10 snowstorms on record for Washington, D.C.:

1. 28.0", Jan 27-28, 1922
2. 20.5", Feb 11-13, 1899
3. 18.7", Feb 18-19, 1979
4. 17.8" Feb 5-6, 2010
5. 17.1", Jan 6-8, 1996
6. 16.7", Feb 15-18, 2003
7. 16.6", Feb 11-12, 1983
8. 16.4", Dec 19-20, 2009 (Snowpocalypse)
9. 14.4", Feb 15-16, 1958
10. 14.4", Feb 7, 1936

Top 9 snowstorms for Philadelphia:

1. 30.7", Jan 7-8, 1996
2. 28.5", Feb 5-6, 2010
3. 23.2", Dec 19-20, 2009
4. 21.3", Feb 11-12, 1983
5. 21.0", Dec 25-26, 1909
6. 19.4", Apr 3-4, 1915
7. 18.9", Feb 12-14, 1899
8. 16.7", Jan 22-24, 1935
9. 15.1", Feb 28-Mar 1, 1941

I'll have a new blog on Monday, when I'll discuss if record snow storms are inconsistent with a world experiencing warming. Have a great Super Bowl weekend, everyone!

Jeff Masters

Winter Weather

Powerful Nor'easter poised to pound Washington D.C. with 2 feet of snow

By: JeffMasters, 3:16 PM GMT on February 05, 2010

A powerful Nor'easter is winding up along the Mid-Atlantic coast of the U.S. this morning, and stands poised to deliver the Washington D.C. region its second huge winter storm of the season tonight and Saturday. While the Nor'easter will affect a relatively small portion of the coast compared to other historic storms, a narrow region of Virginia, Maryland, Washington D.C., Delaware, and New Jersey should see two feet of snow, and three feet are possible in the higher elevation areas to the west of Washington D.C. If the snow amounts top 20.5" in Washington D.C., it will rank as that city's second largest snowstorm on record. Blizzard warnings are posted for Delaware and southern New Jersey, including Atlantic City, where winds will increase to 30 - 35 mph on Saturday, with gusts to 50 mph. Snowfall rates of 2 - 3 inches per hour will create whiteout blizzard conditions near the coast, and snowfall amounts should approach two feet. Lesser snow amounts near a foot are expected in Philadelphia and Pittsburgh, and 4 - 8 inches is expected in New York City.


The top 10 snowstorms on record for Washington, D.C.:

1. January 27-28, 1922 ... 28 inches
2. February 11-13, 1899 ... 20.5 inches
3. February 18-19, 1979 ... 18.7 inches
4. January 6-8, 1996 ... 17.1 inches
5. February 15-18, 2003 ... 16.7 inches
6. February 11-12, 1983 ...16.6 inches
7. December 19-20, 2009 ... 16.4 inches (Snowpocalypse)
8. February 15-16, 1958 ... 14.4 inches
9. February 7, 1936 ... 14.4 inches
10. February 16-18, 1900 ... 14.3 inches


Figure 1. The Nor'easter of February 5 - 6 winds up in this 9:30 am EST image from 2/5/10. Image credit: NASA GOES project.

This weekend's Nor'easter is the second huge winter storm to affect the nation's capital this winter. The December 19, 2009 Nor'easter produced a record 24-hour snowfall in Washington, D.C. and Clifton Forge, Virginia, where nearly 2 feet (61 cm) of snow accumulated. Some interior areas of West Virginia saw 30 inches (76 cm) of snow. The storm broke the record for the amount of snow in a single event in December at Ronald Reagan Washington National Airport, where 16.3 inches (41 cm) of snow accumulated. The storm was the 6th-greatest snowfall in D.C. history. In Philadelphia, snowfall reached 23.2 inches (59 cm), surpassing the 21 inches (53 cm) snowfall of February 11 - 12, 1983, as the city's second-largest, and breaking a 100-year-old record for the largest single December storm, set on December 25 - 26, 1909 (20.2 inches). The largest storm in Philadelphia history was the North American blizzard of 1996, which produced 30.7 inches (78 cm) of snow.

Have a great Super Bowl weekend, everyone!

Jeff Masters

Winter Weather

El Niño weakens from strong to moderate

By: JeffMasters, 2:32 PM GMT on February 03, 2010

El Niño is weakening. Ocean temperatures over the Eastern and Central Pacific have gradually cooled over the past few weeks, and it now appears that the El Niño event of 2009 - 2010 has peaked. Ocean temperatures in the area 5°N - 5°S, 120°W - 170°W, also called the "Niña 3.4 region", crossed below the 1.5°C threshold for a strong El Niño into the "moderate" range in mid-January, and were 1.2°C above average on January 31, according to the Australian Bureau of Meteorology. If temperatures decline further into the 0.5°C - 1.0°C above average range, this will be a "weak" El Niño. The peak warmth of this event appears to have been late December - early January (Figure 1).


Figure 1. Departure of sea surface temperature from average for the Equatorial Pacific Ocean from March 2009 (when La Niña conditions were present) to January 2010. The strongest El Niño conditions were observed December 2009 - January 2010, when temperatures as much as 2 - 2.5°C (dark orange colors) were observed between longitudes 150°W - 170°W. Image credit: NOAA Climate Prediction Center.

The El Niño forecast
Though El Niño appears to have peaked, the decline in SSTs over the Equatorial Pacific may slow and possibly reverse in February, thanks to a burst of stronger-than-average surface westerly winds that has developed near the Date Line. This westerly wind burst is driving a new Kelvin wave of sub-surface warm water towards the coast of South America, which will act to reinforce El Niño over the next month or so. This new Kelvin wave is not as strong as the previous one that propagated eastward over the last few months of 2009, which pushed El Niño over the "strong" threshold. Once the new Kelvin wave subsides in March, it is possible that there will be more westerly wind bursts that will act to drive new Kelvin waves that will reinforce El Niño into the summer. However, El Niño events typically die out in the spring, and most of the El Niño computer forecast models (Figure 2) are predicting an end to El Niño by summer. Note that the last time we had a strong El Niño event--the record El Niño of 1997 - 1998--the event ended very abruptly in May, and a La Niña event developed by the 1998 hurricane season. This resulted in a very active 1998 hurricane season (14 named storms, 10 hurricanes, and 3 major hurricanes, including Category 5 Hurricane Mitch). The recent weakening of El Niño is a likely sign that there will not be El Niño conditions for the coming hurricane season. Only once since 1950 has an El Niño event lasted through two full hurricane seasons, and I don't expect that will occur this time, either. Given that since 1995, the Atlantic has been in an active hurricane period, except for in El Niño years, a more active than normal hurricane season is likely in 2010.


Figure 2. Forecasts made in late January of El Niño from a suite of high-powered global dynamical models and simpler statistical models. Of the dynamical models, 5 are forecasting neutral El Niño conditions by hurricane season (ASO, August-September-October), 2 are forecasting La Niña, and only 1 is forecasting El Niño. For the statistical models, these numbers are 4 neutral, 1 La Niña, and 3 El Niño. Image credit: Columbia University's IRI.

Portlight looking for tents for Haiti
Portlight.org disaster-relief continues to make great progress in Haiti getting aid to those who need it. Portlight has managed to get $100,000 in donated durable medical equipment into Haiti so far, at a cost of just $4500. Paul Timmons, leader of the Portlight relief efforts, wrote this in the latest Portlight.org blog:

OK...gonna make this quick...but we...and by 'we' I mean all of us....have done something that the Federal government has not been able to do: we have opened a direct pipeline for the shipment, delivery and distribution of goods from our Atlanta warehouse directly to our secured location near Port-au-Prince...I have had two calls from USAID officials this morning asking "How'd ya do it?"...and "Can we use it?"

we are making a difference, y'all....



Figure 3. Paul Timmons of Portlight surveys medical beds and crutches being readied for shipment to Haiti.

So, please visit the Portlight.org blog to learn more and to donate. Floodman's blog has the latest info on Portlight's plan for Haitian relief. A few highlights:

Paul Timmons, head of Portlight, has been interviewed by NBC Nightly News at our Atlanta location for a story that will follow one of our shipments from the Atlanta warehouse to its distribution in Haiti. This story will be aired in several parts starting late this week. When scheduling information is given to us we will post it here; tune in and see Paul!

Ron will be on The Barometer Bob Show Thursday night outlining our ongoing efforts in Haiti. We here at Portlight want to thank Bob for his continuing support; he has been a good friend to Portlight and we appreciate his efforts!

On site:
Our primary site coordinator, Richard Lumarque, has been in Haiti for 5 days and has been moving fairly freely from the base at the Quisqueya University; he has been looking at properties that have been offered for tent cities in the Leogane area as well as making contact with a number of people that have been in contact with us here in the US about specific issues. He has contacted the village leaders at Dufort and is working to arrange food deliveries to them.

Further, the latest shipment is expected to be in the Dominican Republic on Thursday. Given the overland route required by the damage in Haiti, we hope to have this shipment in Haiti late in the day on Friday. The delivery and distribution of this shipment will be covered by NBC Nightly News as a part of the aforementioned piece.

We have several additional shipments queued up for transport, including the remainder of the donation from H&H Wholesalers and these will be sent in the next several days; we are investigating a number of additional shipping opportunities that will facilitate quicker lead and delivery times.


Paul will also be on KFPA radio in Berkley, CA at 2pm PST Friday. Tune into http://www.kpfa.org/pushing-limits to hear the show. Paul also appeared on WBAI in New York City on January. Check out their archives to hear the interview.

Next post
I'll have a new post on Friday.

Jeff Masters

Six more weeks of winter!

By: JeffMasters, 3:27 PM GMT on February 02, 2010

Punxsutawney Pennsylvania's famous prognosticating rodent, Punxsutawney Phil, saw his shadow this morning. According to tradition, this means that a solid six more weeks of winter can be expected across the U.S. From the official web site of the Punxsutawney Groundhog Club, groundhog.org:

Here Ye! Here Ye! Here Ye!

On Gobbler's Knob on this fabulous Groundhog Day, February 2nd, 2010
Punxsutawney Phil, the Seer of Seers, Prognosticator of all Prognosticators,
Awoke to the call of President Bill Cooper
And greeted his handlers, Ben Hughes and John Griffiths

After casting a joyful eye toward thousands of his faithful followers,
And a bright sky above me
Showed my shadow beside me.

Six more weeks of winter it will be.


How did this this crazy tradition start?
It all started in Europe, centuries ago, when February 2 was a holiday called Candlemas. On Candlemas, people prayed for mild weather for the remainder of winter. The superstition arose that if a hibernating badger woke up and saw its shadow on Candlemas, there would be six more weeks of severe winter weather. When Europeans settled the New World, they didn't find any badgers. So, they decided to use native groundhogs (aka the woodchuck, land beaver, or whistlepig) as their prognosticating rodent.

What the models say
The latest long-range runs of the ECMWF and GFS models show the jet stream following a typical El Niño winter configuration. A northern branch dipping down over the Northeast U.S. will bring seasonably cold temperatures to the eastern half of the country, with a compensating ridge of high pressure bringing milder temperatures to the Northwest U.S. (and the Winter Olympics in Vancouver, Canada). A second branch of the jet stream will be active across Southern California, Texas, and the Southeast U.S., bringing cooler and rainier weather than average. There are no indications that the jet stream will get "stuck" in a high-amplitude pattern that will bring long-lived record cold to any portion of the country, such as occurred over Florida in early January. At this point, I don't see any reason to disagree with Punxsutawney Phil's fearless forecast of a normal six more weeks of winter.


Figure 1. Departure of winter temperature from average for February. This is a very typical pattern for an El Niño winter. Image credit: NOAA Climate Prediction Center.

Next post
My next post will be Wednesday, when I plan to talk about the status of this year's El Niño.

Jeff Masters

Winter Weather

Interesting hybrid low set to drench Spain's Canary Islands

By: JeffMasters, 3:04 PM GMT on February 01, 2010

An interesting 1002 mb low pressure system with some characteristics of a tropical storm has developed off the coast of Africa, a few hundred miles west-southwest of the Canary Islands. An ASCAT pass from last night revealed top winds of 40 mph near the center, so the low is probably near tropical storm strength. This low is moving east-northeast towards the Canaries, and will likely bring sustained winds of 30 - 35 mph, gusting to 50 mph, to the islands tonight. The storm formed over the weekend from an isolated cold-cored low that was wandering over the Atlantic, and phase space analyses from Florida State University revealed that the low developed a partial warm core over the weekend. A respectable amount of heavy thunderstorm activity has built near the storm's center, characteristic of a tropical storm. The low is over cool 21 - 22°C water, far colder than the typical 26°C needed for a tropical storm to form. These SSTs are about 1 - 2°C warmer than usual for this time of year. Wind shear is marginal for tropical storm formation, about 20 knots. The comma-shaped structure of the storm's spiral bands is characteristic of an extratropical cyclone, and it is pretty unlikely that NHC will view this hybrid storm as being sufficiently tropical to warrant naming it a subtropical depression or subtropical storm. The low is headed towards colder waters of 20°C that lie near the Canary Islands, and the system should become less tropical today.


Figure 1. Hybrid 1002 mb low approaches the Canary Islands, in this visible METEOSAT image from 7am EST 2/1/10.

You can use our wundermap for the Canary Islands to watch the storm roll through the islands. There are two web cams to watch (currently showing thick clouds) that might be interesting. EUMETSAT satellite images loops will also be interesting.

Next post
My next post will be Tuesday (Groundhog's Day), when I plan to discuss Punxsutawney Phil's forecast for the rest of winter. I'll throw in my two cents worth, too.

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