Arctic sea ice loss tied to unusual jet stream patterns
Earth has seen some highly unusual weather patterns over the past three years, and three new studies published this year point to Arctic sea loss as a potential important driver of some of these strange weather patterns. The record loss of sea ice the Arctic in recent years may be increasing winter cold surges and snowfall in Europe and North America, says a study by a research team led by Georgia Institute of Technology scientists Jiping Liu and Judith Curry. The paper, titled "Impact of declining Arctic sea ice on winter snowfall", was published on Feb. 27, 2012 in the online early edition of the journal Proceedings of the National Academy of Sciences. "Our study demonstrates that the decrease in Arctic sea ice area is linked to changes in the winter Northern Hemisphere atmospheric circulation, said Judith Curry, chair of the School of Earth and Atmospheric Sciences at Georgia Tech, in a press release. "The circulation changes result in more frequent episodes of atmospheric blocking patterns, which lead to increased cold surges and snow over large parts of the northern continents."
Figure 1. Arctic sea ice in September 2007 reached its lowest extent on record, approximately 40% lower than when satellite records began in 1979. Sea ice loss in 2011 was virtually tied with the ice loss in 2007, despite weather conditions that were not as unusual in the Arctic. Image credit: University of Illinois Cryosphere Today.
Figure 2. The extent of Arctic sea ice loss in the summer July - August - September period in 2007 was about 1.4 million square miles (3.6 million square kilometers) greater than in 1980, according to the University of Illinois Cryosphere Today. For comparison, the lost ice coverage (orange colors) was equal to an area about 44% of the size of the contiguous U.S., or 71% of the non-Russian portion of Europe.
Summertime Arctic sea ice loss: 40% since 1980
The Arctic has seen a stunning amount of sea ice loss in recent years, due to melting and unfavorable winds that have pushed large amounts of ice out of the region. Forty percent of the sea ice was missing in September 2007, compared to September of 1980. This is an area equivalent to about 44% of the contiguous U.S., or 71% of the non-Russian portion of Europe. Such a large area of open water is bound to cause significant impacts on weather patterns, due to the huge amount of heat and moisture that escapes from the exposed ocean into the atmosphere over a multi-month period following the summer melt. The Georgia Tech study found that Arctic sea ice loss had caused a 20 - 60% weakening of the west-to-east belt of winds circling the pole in recent years, producing broader meanders in the jet stream that allowed it to get "stuck" in place 20 - 60% more often. When the jet stream gets stuck in place for a long period of time, we say a "blocking pattern" has set up. Since the jet stream marks the boundary between cold, Arctic air to the north, and warmer subtropical air to the south, areas on both sides of the jet are subjected to extended periods of unusually warm or cold weather during a blocking episode. Such a blocking pattern began on January 26, 2012 and lasted until February 11, bringing and exceptionally cold and snowy conditions to much of Europe, which lay on the cold side of an elongated loop of the jet stream that got stuck in place. Conversely, most of North America and northern Siberia saw unusually warm temperatures during this period, since they were on the warm side of the jet stream. Lead author Jiping Liu, a senior research scientist in the School of Earth and Atmospheric Sciences at Georgia Tech, added, "We think the recent snowy winters could be caused by the retreating Arctic ice altering atmospheric circulation patterns by weakening westerly winds, increasing the amplitude of the jet stream and increasing the amount of moisture in the atmosphere. These pattern changes enhance blocking patterns that favor more frequent movement of cold air masses to middle and lower latitudes, leading to increased heavy snowfall in Europe and the Northeast and Midwest regions of the United States." The paper concludes: "if Arctic sea ice continues as anticipated by climate modeling results, we speculate that episodes of the aforementioned circulation change will become more frequent, along with more persistent snowstorms over northern continents during winter."
Figure 3. Waiting for the warm-up after a rare snowfall in Italy during the February, 2012 European cold blast. Image credit: wunderphotographer cathykiro.
Two other studies link Arctic sea ice loss to atmospheric circulation changes
"The question is not whether sea ice loss is affecting the large-scale atmospheric circulation...it's how can it not?" That was the take-home message from Dr. Jennifer Francis of Rutgers University, in her talk "Evidence Linking Arctic Amplification to Extreme Weather in Mid-latitudes, presented at December's American Geophysical Union meeting in San Francisco. Dr. Francis presented new research that has just been published in the journal Geophysical Research Letters, which shows that Arctic sea ice loss may significantly affect the upper-level atmospheric circulation, slowing its winds and increasing its tendency to make contorted high-amplitude loops. High-amplitude loops in the upper level wind pattern (and associated jet stream) increases the probability of persistent weather patterns in the Northern Hemisphere, potentially leading to extreme weather due to longer-duration cold spells, snow events, heat waves, flooding events, and drought conditions. Dr. Francis describes her work in a March 5, 2012 post on the Yale environment360 web site.
"Even if the current weather situation may seem to speak against it, the probability of cold winters with much snow in Central Europe rises when the Arctic is covered by less sea ice in summer." That was the opening sentence of a January 26, 2012 press release by a group of European scientists, led by Ralf Jaiser of the Alfred Wegener Institute in Germany. The words proved prescient, because that day marked the beginning of a brutal two-week cold air outbreak over Central and Eastern Europe that killed 823 people and did over $660 million in damage, according to preliminary estimates by insurance broker Aon Benfield. Dr. Jaiser's team, using modeling studies, showed that Arctic sea ice loss weakens upper-level winds over the Arctic in winter, allowing an increased chance of cold air surges over Europe.
Figure 4. Digging out in Maryland after "Snowmageddon" on February 4, 2010. Image credit: wunderphotographer chills.
Why was the winter of 2011 - 2012 so warm in the U.S.?
The winter of 2011 - 2012 in North America was unusually warm--the fourth warmest on record. The cold air spilling out of the Arctic during the winter was confined to Europe, unlike that previous two winters, which were unusually cold and snowy in the Eastern U.S. Obviously, loss of Arctic sea ice is not having the same impact each winter; such factors as El Niño/La Niña, the phase of the 11-year sunspot cycle, and the amount of snow cover in Siberia also have strong influences on the winter weather pattern that sets up. Cold air is less likely to spill out of the Arctic during a solar maximum, as we are now headed towards, so this factor may tend to reduce the odds of getting big cold blasts in the U.S. during the coming two winters. However, cold air may be more likely to spill out of the Arctic in winter due to the decades-long pattern of warming and cooling of Atlantic Ocean waters known as the Atlantic Multidecadal Oscillation (AMO). A 2012 study by NASA scientists found that the warm phase of the AMO (like we have been in since 1995) causes more instances of atmospheric blocking, where the jet stream gets "stuck" in place, leading to long periods of extreme weather. It will be interesting to see how all these factors play out in the coming years. If these three newly-published studies are correct, the U.S. should see more winters like 2010 - 2011 and 2009 - 2010 in coming decades, as Arctic sea ice continues to melt and affect global atmospheric circulation patterns more strongly.
References
Francis, J.A., and S.J. Vavrus (2012), "Evidence linking Arctic amplification to extreme weather in mid-latitudes," Geophysical Research Letters, 21 February, 2012.
Jaiser, R., K. Dethloff, D. Handorf, A. Rinke, J. Cohen (2012), Impact of sea ice cover changes on the Northern Hemisphere atmospheric winter circulation, Tellus A 2012, 64, 11595, DOI: 10.3402/tellusa.v64i0.11595
Liu et al. (2012), "Impact of declining Arctic sea ice on winter snowfall", Proc. Natl. Academy of Sciences, Published online before print February 27, 2012, doi: 10.1073/pnas.1114910109
Jeff Masters
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showing damage right now
new tornado warning in the line to the west.
Euless storm with Baseball Hail. Euless storm looking VERY DANGEROUS on radar near Irving!
000
WFUS54 KFWD 031903
TORFWD
TXC121-031945-
/O.NEW.KFWD.TO.W.0007.120403T1903Z-120403T1945Z/
BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE FORT WORTH TX
203 PM CDT TUE APR 3 2012
THE NATIONAL WEATHER SERVICE IN FORT WORTH HAS ISSUED A
* TORNADO WARNING FOR...
DENTON COUNTY IN NORTH CENTRAL TEXAS...
* UNTIL 245 PM CDT
* AT 203 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO 6 MILES
SOUTHWEST OF JUSTIN...MOVING NORTHEAST AT 40 MPH.
* THE TORNADO WILL BE NEAR...
JUSTIN...NORTHLAKE AND CORRAL CITY AROUND 210 PM CDT...
PONDER AROUND 215 PM CDT...
DENTON AROUND 225 PM CDT...
KRUM AROUND 230 PM CDT...
SANGER AROUND 240 PM CDT...
RAY ROBERTS PARK ISLE DU BOIS AROUND 245 PM CDT...
THIS WILL IMPACT I-35 BETWEEN MILE MARKERS 473 AND 482.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
MOVE TO AN INTERIOR BATHROOM...CLOSET...OR HALLWAY ON THE LOWEST
FLOOR OF YOUR BUILDING. COVER YOURSELF WITH BLANKETS...PILLOWS...OR A
MATTRESS FOR PROTECTION.
&&
LAT...LON 3341 9688 3300 9731 3299 9740 3319 9740
3342 9736
TIME...MOT...LOC 1903Z 208DEG 33KT 3306 9735
$$
BUNTING
TXC085-113-397-032015-
/O.NEW.KFWD.TO.W.0008.120403T1913Z-120403T2015Z/
BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE FORT WORTH TX
213 PM CDT TUE APR 3 2012
THE NATIONAL WEATHER SERVICE IN FORT WORTH HAS ISSUED A
* TORNADO WARNING FOR...
SOUTHEASTERN COLLIN COUNTY IN NORTH CENTRAL TEXAS...
NORTHEASTERN DALLAS COUNTY IN NORTH CENTRAL TEXAS...
WESTERN ROCKWALL COUNTY IN NORTH CENTRAL TEXAS...
* UNTIL 315 PM CDT
* AT 212 PM CDT...A SEVERE THUNDERSTORM WITH A HISTORY OF PRODUCING
DAMAGING TORNADOES WAS 6 MILES WEST OF SUNNYVALE...MOVING
NORTHEAST AT 30 MPH. THIS IS A DANGEROUS STORM! SEEK SHELTER NOW!
* THE TORNADO WILL BE NEAR...
GARLAND...ROWLETT AND HEATH AROUND 220 PM CDT...
PARKER AROUND 235 PM CDT...
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A TORNADO HAS BEEN CONFIRMED WITH THIS STORM! THIS IS AN EXTREMELY
DANGEROUS SITUATION. IF YOU ARE IN THE PATH OF THIS DESTRUCTIVE
STORM...TAKE COVER IMMEDIATELY.
&&
LAT...LON 3323 9629 3299 9637 3281 9650 3281 9652
3279 9652 3277 9666 3280 9676 3326 9658
3326 9630
TIME...MOT...LOC 1912Z 205DEG 28KT 3286 9664
$$
DUNN
Everything is bigger in Texas.
Soooo not funny right now.
That's nice.......
Classic stovepipe tornado.
Welcome to the party my friend! Several news outlets have reported fatalities.
URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 135
NWS STORM PREDICTION CENTER NORMAN OK
235 PM CDT TUE APR 3 2012
THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF
FAR SOUTHWEST ARKANSAS
NORTHWEST LOUISIANA
EASTERN TEXAS
EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 235 PM UNTIL
1000 PM CDT.
TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.
THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 65 STATUTE
MILES EAST AND WEST OF A LINE FROM 75 MILES NORTH NORTHWEST OF
SHREVEPORT LOUISIANA TO 25 MILES SOUTHWEST OF LUFKIN TEXAS. FOR
A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU5).
REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.
OTHER WATCH INFORMATION...CONTINUE...WW 132...WW 133...WW 134...
DISCUSSION...SEVERE STORMS IN PROGRESS OVER N-CNTRL TX ARE EXPECTED
TO MOVE/DEVELOP EWD ACROSS THE WATCH AREA THIS AFTERNOON INTO
EVENING IN ADVANCE OF MIDLEVEL VORTICITY MAXIMUM LIFTING NEWD
THROUGH THE RED RIVER VALLEY. AMBIENT WARM SECTOR AIR MASS
/CHARACTERIZED BY MLCAPE OF 2000-2500 J PER KG/ WILL REMAIN BOUND ON
THE N BY AN W-E ORIENTED OUTFLOW BOUNDARY SITUATED JUST N OF THE
I-20 CORRIDOR. BOTH LOW AND DEEP-LAYER SHEAR WILL STRENGTHEN WITH
THE EWD PROGRESSION OF THE VORTICITY MAXIMUM...RESULTING IN AN
ENVIRONMENT SUPPORTIVE OF SUPERCELLS. THE GREATEST RISK FOR
TORNADOES WILL EXIST WITH STORMS INTERACTING WITH OUTFLOW BOUNDARY
WHERE LOW-LEVEL SHEAR/VORTICITY IS ENHANCED. IN ADDITION TO THE
TORNADO THREAT...VERY LARGE HAIL WILL BE POSSIBLE AS WILL LOCALLY
DAMAGING STRAIGHT-LINE WINDS.
AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 22030.
...MEAD
MSZ019-025-027-034>036-041-032010-
WASHINGTON MS-SUNFLOWER MS-SHARKEY MS-LEFLORE MS-HUMPHREYS MS-
HOLMES MS-CARROLL MS-
230 PM CDT TUE APR 3 2012
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE JACKSON MS
230 PM CDT TUE APR 3 2012
A LINE OF STRONG THUNDERSTORMS CAPABLE OF PRODUCING PEA TO DIME SIZE
HAIL AND 40 TO 50 MPH WINDS WAS LOCATED FROM 5 MILES NORTH OF ITTA
BENA TO DELTA CITY AT 231 PM CDT...MOVING SOUTHEAST AT 40 MPH.
VERY HEAVY RAIN ALONG WITH CONTINUOUS CLOUD TO GROUND LIGHTNING ARE
ALSO POSSIBLE WITH THESE STORMS.
PEOPLE IN SOUTHWESTERN CARROLL...WESTERN HOLMES...HUMPHREYS...
LEFLORE...NORTHEASTERN SHARKEY...SOUTHEASTERN SUNFLOWER AND CENTRAL
WASHINGTON COUNTIES SHOULD MONITOR THESE STORMS CLOSELY.
LAT...LON 3348 8985 3309 9004 3298 9026 3301 9033
3302 9034 3301 9036 3301 9044 3293 9045
3292 9057 3309 9099 3331 9057 3369 9038
TIME...MOT...LOC 1931Z 296DEG 35KT 3356 9031 3326 9046
3309 9078
$$
JC
Look at those storms on the Arkansas Louisiana border- they are not moving at all- flash flooding is a major concern there, and the NWS does have warnings out...
Big tornado in city =/= monthly tornado activity
Yikes!
I can pick out a couple hooks on that image- no tornado warnings though
You can "expect" a hurricane but not a tornado. This is what tornadoes do, how they are and always have been and how they will be as long as Earth has an atmosphere. And... pure and simple, it is Spring on the Southern Plains.
People die when they don't pay attention or think it won't happen to them. Some die, many of them in lower economic ranges, because they have no shelter. Some even die when they stay alert, pay attention and do everything they can to protect themselves.
I am sorry for those neighbors across Red River affected by these storms today.
Looks like two hooks. More twins?
NATIONAL WEATHER SERVICE FORT WORTH TX
315 PM CDT TUE APR 3 2012
THE NATIONAL WEATHER SERVICE IN FORT WORTH HAS ISSUED A
* TORNADO WARNING FOR...
EASTERN DALLAS COUNTY IN NORTH CENTRAL TEXAS...
NORTHWESTERN KAUFMAN COUNTY IN NORTH CENTRAL TEXAS...
ROCKWALL COUNTY IN NORTH CENTRAL TEXAS...
* UNTIL 400 PM CDT
* AT 314 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO 6 MILES WEST OF
SEAGOVILLE...MOVING NORTHEAST AT 30 MPH. THERE IS ANOTHER STORM
WHICH MAY PRODUCE A TORNADO JUST EAST OF DALLAS...ALSO MOVING
NORTHEAST AT 30 MPH. THESE TWO STORMS ARE VERY DANGEROUS AND BOTH
CAPABLE OF PRODUCING TORNADOES...IF YOU ARE IN THE PATH OF THESE
STORMS...TAKE COVER IMMEDIATELY!
* THE TORNADO WILL BE NEAR...
SEAGOVILLE AROUND 320 PM CDT...
BALCH SPRINGS AROUND 325 PM CDT...
MESQUITE AROUND 330 PM CDT...
FORNEY AND SUNNYVALE AROUND 335 PM CDT...
GARLAND AROUND 340 PM CDT...
HEATH...LAWRENCE AND ROWLETT AROUND 345 PM CDT...
THIS WILL IMPACT THE FOLLOWING INTERSTATES...
I-35E BETWEEN MILE MARKERS 48 AND 61...
I-20 BETWEEN MILE MARKERS 473 AND 476...
I-30 BETWEEN MILE MARKERS 42 AND 66...
I-45 BETWEEN MILE MARKERS 276 AND 284...
I-635 BETWEEN MILE MARKERS 1 AND 24.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TO PROTECT YOUR LIFE...TAKE COVER NOW! MOVE UNDERGROUND OR TO AN
INTERIOR ROOM ON THE LOWEST FLOOR OF A STURDY BUILDING. AVOID
WINDOWS. IF IN A MOBILE HOME...A VEHICLE OR OUTDOORS...MOVE TO THE
CLOSEST SUBSTANTIAL SHELTER AND PROTECT YOURSELF FROM FLYING DEBRIS.
Viewing: 701 - 751
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