Dr. Jeff Masters' WunderBlog

Florida shivers; Hot Arctic-Cold Continents pattern is back

Posted by: Dr. Jeff Masters, 5:36 PM GMT on December 14, 2010

Cold air sweeping southwards behind the fierce snowstorm that roared through the Upper Midwest over the weekend is bringing record low temperatures over much of the Southeast this morning. However, preliminary indications are that Central Florida's orange groves fared better than expected, and there were no reports of widespread damage to the orange crop. Record lows this morning included 32°F at West Palm Beach, 50°F in Key West, and 20°F in Jacksonville. Cold air flowing over the relatively warm waters of Lake Erie and Lake Ontario are creating heavy lake-effect snows, with 5 – 9 inches of new snow expected near Cleveland, OH today, and 2 – 5 inches near Syracuse, NY.

Hot Arctic-Cold Continents
I'm in San Francisco this week for the world's largest gathering of Earth scientists, the annual American Geophysical Union (AGU) conference. Over 15,000 scientists have descended upon the city, and there are a ridiculous number of fascinating talks on every conceivable aspect of Earth science, including, of course, climate change. One talk I attended yesterday was called, "Hot Arctic-Cold Continents: Hemispheric Impacts of Arctic Change.” The talk was given by Dr. Jim Overland of NOAA's Pacific Marine Environmental Laboratory, one of the world's experts on Arctic weather and climate (I spent many long months flying in the Arctic with him during the three Arctic field programs I participated in during the late 1980s.) Dr. Overland discussed the remarkable winter of 2009 – 2010, which brought record snowstorms to Europe and the U.S. East Coast, along with the coldest temperatures in 25 years, but also brought the warmest winter on record to Canada and much of the Arctic. He demonstrated that the Arctic is normally dominated by low pressure in winter, and a “Polar Vortex” of counter-clockwise circulating winds develops surrounding the North Pole. However, during the winter of 2009-2010, high pressure replaced low pressure over the Arctic, and the Polar Vortex weakened and even reversed at times, with a clockwise flow of air replacing the usual counter-clockwise flow of air around the pole. This unusual flow pattern allowed cold air to spill southwards and be replaced by warm air moving poleward. This pattern is kind of like leaving the refrigerator door ajar--the refrigerator warms up, but all of the cold air spills out into the house.

Figure 1. Conceptual diagram of how Arctic sea ice loss affects winter weather, from NOAA's Future of Arctic Sea Ice and Global Impacts web page.

The North Atlantic Oscillation (NAO)
This is all part of a natural climate pattern known as the North Atlantic Oscillation (NAO), which took on its most extreme configuration in 145 years of record keeping during the winter of 2009 – 2010. The NAO is a climate pattern in the North Atlantic Ocean of fluctuations in the difference of sea-level pressure between the Icelandic Low and the Azores High. It is one of oldest known climate oscillations--seafaring Scandinavians described the pattern several centuries ago. Through east-west oscillation motions of the Icelandic Low and the Azores High, the NAO controls the strength and direction of westerly winds and storm tracks across the North Atlantic. A large difference in the pressure between Iceland and the Azores (positive NAO) leads to increased westerly winds and mild and wet winters in Europe. Positive NAO conditions also cause the Icelandic Low to draw a stronger south-westerly flow of air over eastern North America, preventing Arctic air from plunging southward. In contrast, if the difference in sea-level pressure between Iceland and the Azores is small (negative NAO), westerly winds are suppressed, allowing Arctic air to spill southwards into eastern North America more readily. Negative NAO winters tend to bring cold winters to Europe and the U.S. East Coast, but leads to very warm conditions in the Arctic, since all the cold air spilling out of the Arctic gets replaced by warm air flowing poleward.

The winter of 2009 - 2010 had the most extreme negative NAO since record keeping began in 1865. This "Hot Arctic-Cold Continents pattern", resulting in a reversal of Polar Vortex and high pressure replacing low pressure over the Arctic, had occurred previously in only four winters during the past 160 years—1969, 1963, 1936, and 1881. Dr. Overland called the winter of 2009 – 2010 at least as surprising at the record 2007 loss of Arctic sea ice. He suspected that Arctic sea ice loss was a likely culprit for the event, since Francis et al. (2009) found that during 1979 - 2006, years that had unusually low summertime Arctic sea ice had a 10 - 20% reduction in the temperature difference between the Equator and North Pole. This resulted in a weaker jet stream with slower winds that lasted a full six months, through fall and winter. The weaker jet caused a weaker Aleutian Low and Icelandic Low during the winter, resulting in a more negative North Atlantic Oscillation, allowing cold air to spill out of the Arctic and into Europe and the Eastern U.S. Dr. Overland also stressed that natural chaos in the weather/climate system also played a role, as well as the El Niño/La Niña cycle and natural oscillations in stratospheric winds. Not every year that we see extremely high levels of Arctic sea ice loss will have a strongly negative NAO winter. For example, the record Arctic sea ice loss year of 2007 saw only a modest perturbation to the Arctic Vortex and the NAO during the winter of 2007 – 2008.

However, the strongly negative NAO is back again this winter. High pressure has replaced low pressure over the North Pole, and according to NOAA, the NAO index during November 2010 was the second lowest since 1950. This strongly negative NAO has continued into December, and we are on course to have a top-five most extreme December NAO. Cold air is once again spilling southwards into the Eastern U.S. And Europe, bringing record cold and fierce snowstorms. At the same time, warm air is flowing into the Arctic to replace the cold air spilling south--temperatures averaged more than 10°C (18°F) above average over much of Greenland so far this month. The latest 2-week forecast from the GFS model predicts that the Hot Arctic-Cold Continents pattern will continue for the next two weeks. However, the coldest air has sloshed over into Europe and Asia, and North America will see relatively seasonable temperatures the next two weeks.

For more information
The NOAA web page, Future of Arctic Sea Ice and Global Impacts has a nice summary of the “Hot Arctic-Cold Continents” winter pattern.

NOAA's Arctic Report Card is also a good source of information.

Francis, J. A., W. Chan, D. J. Leathers, J. R. Miller, and D. E. Veron, 2009: Winter northern hemisphere weather patterns remember summer Arctic sea-ice extent. Geophys. Res. Lett., 36, L07503, doi:10.1029/2009GL037274.

Honda, M., J. Inoue, and S. Yamane, 2009: Influence of low Arctic sea-ice minima on anomalously cold Eurasian winters. Geophys. Res. Lett., 36, L08707, doi:10.1029/2008GL037079.

Overland, J. E., and M. Wang, 2010: Large-scale atmospheric circulation changes associated with the recent loss of Arctic sea ice. Tellus, 62A, 1.9.

Petoukhov, V., and V. Semenov, 2010: A link between reduced Barents-Kara sea ice and cold winter extremes over northern continents. J. Geophys. Res.-Atmos., ISSN 0148-0227.

Seager, R., Y. Kushnir, J. Nakamura, M. Ting, and N. Naik (2010), Northern Hemisphere winter snow anomalies: ENSO, NAO and the winter of 2009/10, Geophys. Res. Lett., 37, L14703, doi:10.1029/2010GL043830.

Jeff Masters

Peeking Christmas Lights in Snowy Shrub (UnobtrusiveTroll10)

At my house. Their little heat has created a tiny viewing hole.

Berry Cold Strawberries (lshunter)

Astin Farms in Plant City, FL waters their strawberry crop to prevent damage from frost as temperatures drop into the 20s overnight on December 14, 2010. More cold temperatures expected tonight.

Categories: Climate Change Sea Ice Winter Weather

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251. JRRP 2:15 PM GMT on December 15, 2010
Member Since: August 16, 2007 Posts: 0 Comments: 4305

253. RipplinH2O 2:34 PM GMT on December 15, 2010
Howdy all. A brisk but beautiful blue sky Wednesday morning on the beach. Back in the high 60's tomorrow. Boat trip and golfable this weekend... Member Since: July 30, 2010 Posts: 0 Comments: 491

256. Orcasystems 3:13 PM GMT on December 15, 2010
Complete Update For those of you on the cold side.. this will help. A recipe for CANADIAN NAVY Moose Milk: Give vehicle keys to a party staying sober Add: 1.14 litre (40 oz for my American friends) DARK Rum 1.14 litre Kahlua 1.14 litre Vodka 4 litres of Vanilla soft scoop ice cream 4 litres of partly skimmed milk (have to be health conscience) Mix gently until frothy with still a few ice cream lumps Liberally sprinkle nutmeg over top Enjoy Member Since: October 1, 2007 Posts: 77 Comments: 26077

257. Minnemike 3:18 PM GMT on December 15, 2010
Quoting Orcasystems: Complete Update For those of you on the cold side.. this will help. A recipe for CANADIAN NAVY Moose Milk: Give vehicle keys to a party staying sober Add: 1.14 litre (40 oz for my American friends) DARK Rum 1.14 litre Kahlua 1.14 litre Vodka 4 litres of Vanilla soft scoop ice cream 4 litres of partly skimmed milk (have to be health conscience) Mix gently until frothy with still a few ice cream lumps Liberally sprinkle nutmeg over top Enjoy that's now on the menu for this year's get together :D Member Since: July 31, 2008 Posts: 0 Comments: 1255

259. Orcasystems 3:22 PM GMT on December 15, 2010
Quoting RIDGES: I'm glad you are looking out for my health Orca. Yes, I will be trying it. KOG missed out on snow again. Inquiring minds would like to know how you feel about that. :) I would not mind seeing KOG under about 3 feet of snow. We have been getting hammered by the pineapple express... 3 in a row... Caution on the Moose Milk... it sneaks up very very quietly...and fast. Member Since: October 1, 2007 Posts: 77 Comments: 26077

261. HurricaneKatrina 3:52 PM GMT on December 15, 2010
Its annoying when people use cold to say gw is a hoax. This is the new normal. If the gulf stream shuts off we are in big trouble! Member Since: August 19, 2008 Posts: 27 Comments: 267

262. HurricaneKatrina 3:55 PM GMT on December 15, 2010
Global superstorm kind of trouble? Maybe... http://library.thinkquest.org/04apr/00420/introduction/team_superstorm2.htm http://www.terracycles.com/joomla/index.php?option=com_content&view=article&id=3:superstormexplanat ion&catid=1:earth&Itemid=5 http://library.thinkquest.org/C006494/html/superstorm.htm Member Since: August 19, 2008 Posts: 27 Comments: 267

264. NRAamy 4:02 PM GMT on December 15, 2010
SQUAWK!!!!! Member Since: January 24, 2007 Posts: 315 Comments: 31937

265. HurricaneKatrina 4:02 PM GMT on December 15, 2010
Quoting NavarreMark: If the corn doesn't polinate were in even bigger trouble. I worry about that at night. We would be. but there is no sign of that happening. Member Since: August 19, 2008 Posts: 27 Comments: 267

266. KEEPEROFTHEGATE (Mod) 4:02 PM GMT on December 15, 2010
Quoting Orcasystems: I would not mind seeing KOG under about 3 feet of snow. We have been getting hammered by the pineapple express... 3 in a row... Caution on the Moose Milk... it sneaks up very very quietly...and fast. are you asking for 3 feet of snow orca is that what you are sayin Member Since: July 15, 2006 Posts: 143 Comments: 40497

267. HurricaneKatrina 4:03 PM GMT on December 15, 2010
http://www.globalsuperstorm.bravehost.com/whatis.html Member Since: August 19, 2008 Posts: 27 Comments: 267

268. NRAamy 4:04 PM GMT on December 15, 2010
three feet of snow works for me.... Member Since: January 24, 2007 Posts: 315 Comments: 31937

269. HurricaneKatrina 4:04 PM GMT on December 15, 2010
Quoting KEEPEROFTHEGATE: are you asking for 3 feet of snow orca is that what you are sayin Imagine 10x that amount. http://www.globalsuperstorm.bravehost.com/whatis.html http://library.thinkquest.org/04apr/00420/introduction/team_superstorm2.htm http://www.terracycles.com/joomla/index.php?option=com_content&view=article&id=3:superstormexplanat ion&catid=1:earth&Itemid=5 http://library.thinkquest.org/C006494/html/superstorm.htm Cut and paste the links. Member Since: August 19, 2008 Posts: 27 Comments: 267

272. HurricaneKatrina 4:08 PM GMT on December 15, 2010
Quoting NavarreMark: Exactly. The effects of GW are everywhere. You would have to be living under a rock to not notice. Hope that rock protects against global superstorms! http://www.globalsuperstorm.bravehost.com/prevention.html Member Since: August 19, 2008 Posts: 27 Comments: 267

273. HurricaneKatrina 4:10 PM GMT on December 15, 2010
Quoting HurricaneKatrina: The effects of GW are everywhere. You would have to be living under a rock to not notice. Hope that rock protects against global superstorms! http://www.globalsuperstorm.bravehost.com/prevention.html http://www.globalsuperstorm.bravehost.com/whyshouldyoulisten.html 2 billion could freeze. Member Since: August 19, 2008 Posts: 27 Comments: 267

274. hurricanejunky 4:11 PM GMT on December 15, 2010
The good old Davis Weather Station registered 27 this morning here in North Fort Myers, FL. It was COLD!!! Frost galore...not sure how much more the plants can take! It's GREAT holiday weather though....I hope you all fared well last evening. Not sure of the crop damage...any word on that yet? Member Since: August 28, 2006 Posts: 6 Comments: 2875

275. Neapolitan 4:13 PM GMT on December 15, 2010
It's come to light just this morning just why some TV viewers--that is, those who get their news and information primarily/solely from one particular cable network--may be less inclined to believe the overwhelming evidence supporting the theory of AGW. Story I personally accept input from many different sources. Some I agree with, some I don't, but mostly I try not to judge either way until and unless a particular source proves to be manipulative and untrustworthy, at which point I tend to ignore it for the most part. Where science is concerned--or, for that matter, just about anything else: politics, religion, sports, art, whatever--I'd like to politely suggest that everyone stretch their intellectual horizons a bit by reading books and magazines and websites they normally wouldn't, and listening to or watching TV and radio stations they normally wouldn't. You're doing yourself--and the world--a huge disservice by not doing so. Member Since: November 8, 2009 Posts: 4 Comments: 11153

276. HurricaneKatrina 4:14 PM GMT on December 15, 2010
Quoting Neapolitan: It's come to light just this morning just why some TV viewers--that is, those who get their news and information primarily/solely from one particular cable network--may be less inclined to believe the overwhelming evidence supporting the theory of AGW. Story I personally accept input from many different sources. Some I agree with, some I don't, but mostly I try not to judge either way until and unless a particular source proves to be manipulative and untrustworthy, at which point I tend to ignore it for the most part. Where science is concerned--or, for that matter, just about anything else: politics, religion, sports, art, whatever--I'd like to politely suggest that everyone stretch their intellectual horizons a bit by reading books and magazines and websites they normally wouldn't, and listening to or watching TV and radio stations they normally wouldn't. You're doing yourself--and the world--a huge disservice by not doing so. Some people will be in denial even after the global superstorm freezes 2 billion day after tomorrow style. Member Since: August 19, 2008 Posts: 27 Comments: 267

277. atmoaggie 4:15 PM GMT on December 15, 2010
Quoting HurricaneKatrina: http://www.globalsuperstorm.bravehost.com/whatis.html That's absurd. So some layman thinks that everything they see in the movie is real. So what? Member Since: August 16, 2007 Posts: 6 Comments: 12461

278. Minnemike 4:15 PM GMT on December 15, 2010
Hey HurricaneKatrina... ever hear of a superstorm? :P Member Since: July 31, 2008 Posts: 0 Comments: 1255

280. HurricaneKatrina 4:17 PM GMT on December 15, 2010
Quoting atmoaggie: That's absurd. So some layman think that everything they see in the movie is real. So what? Ever heard of a downdraft? It COOLS dramatically. Member Since: August 19, 2008 Posts: 27 Comments: 267

281. HurricaneKatrina 4:19 PM GMT on December 15, 2010
It would start like this http://www.spc.noaa.gov/coolimg/nc_storm/index.html http://www.ask.com/wiki/Downburst?qsrc=3044 Member Since: August 19, 2008 Posts: 27 Comments: 267

282. JRRP 4:27 PM GMT on December 15, 2010
Quoting Jeff9641: Hard to believe that the Euro is showing EL-Nino by October 2011. The Euro has seemed to be nailing everything lately and wouldn't be surprised if that pans out. Next years Winter season could be a strong EL-Nino. Very wacky wx patterns again for next Winter. -1 :P Member Since: August 16, 2007 Posts: 0 Comments: 4305

283. RipplinH2O 4:28 PM GMT on December 15, 2010
Nea, open your link and click on the "about us" link in the upper right. It says "Media Matters for America is a Web-based, not-for-profit, 501(c)(3) progressive research and information center dedicated to comprehensively monitoring, analyzing, and correcting conservative misinformation in the U.S. media." You obviously think FOX is biased but countering perceived bias with bias? Really?... Member Since: July 30, 2010 Posts: 0 Comments: 491

284. lightningbolt73 4:31 PM GMT on December 15, 2010
Good morning all! I don't think it got as cold as forecast here, which is good thing! Great we're supposed to be 70 tomorrow! A friend of mine was bragging how it got up in the 60s yesterday in Dallas where he lives, but I told him that on Friday when we'll be 76 he'll have highs in the 40s! Member Since: October 19, 2010 Posts: 0 Comments: 112

285. eddye 4:33 PM GMT on December 15, 2010
jeff 9641 how cold does the gfs show after christmas Member Since: August 12, 2008 Posts: 0 Comments: 983

286. SQUAWK 4:34 PM GMT on December 15, 2010
AMY!!!!! Member Since: December 9, 2008 Posts: 0 Comments: 2497

289. atmoaggie 4:47 PM GMT on December 15, 2010
Quoting HurricaneKatrina: Ever heard of a downdraft? It COOLS dramatically. ? Go ask someone along the front range of the rockies what really happens when air descends. (And see today's temps in Colorado) Without torrential rainfall. And if you want something with actual science behind it, look up adiabatic heating. Member Since: August 16, 2007 Posts: 6 Comments: 12461

290. reedzone 4:47 PM GMT on December 15, 2010
12Z GFS back on board with the snowstorm as the 06Z DGEX (NAM) takes it out to sea. However, it showed a nice storm on the 18Z last night. Not sure what to make out but I am confident that Long Island will get some snowfall with this one! Member Since: July 1, 2008 Posts: 13 Comments: 7247

292. Neapolitan 4:50 PM GMT on December 15, 2010
Quoting RipplinH2O: Nea, open your link and click on the "about us" link in the upper right. It says "Media Matters for America is a Web-based, not-for-profit, 501(c)(3) progressive research and information center dedicated to comprehensively monitoring, analyzing, and correcting conservative misinformation in the U.S. media." You obviously think FOX is biased but countering perceived bias with bias? Really?... Hey, I said nothing about conservative or progressive; I merely pointed at a story about a particular source of real disinformation. But if you want to kill the messenger while ignoring the message, that's fine; just choose any of the many other websites reporting the same story. Here, try this handy URL. I can understand the discomfort some have with Media Matters; if I were a "journalist" doing sketchy things, I, too, would be nervous about an organization that exists to analyze and correct media misinformation. ;-) Member Since: November 8, 2009 Posts: 4 Comments: 11153

294. JRRP 4:53 PM GMT on December 15, 2010
Quoting Jeff9641: Let me guess you don't know how to read your graph which shows what appears to be an EL-Nino building come September. Depending on strength could have a big impact at the peak of next years hurricane season. could be... but no necessary Member Since: August 16, 2007 Posts: 0 Comments: 4305

295. RipplinH2O 4:57 PM GMT on December 15, 2010
You miss my point: Media Matters isn't watchdogging "journalist(s) doing sketchy things", they watch the conservative press. Now, had they left out the word "conservative" in their mission statement and stated "Media Matters for America is a Web-based, not-for-profit, 501(c)(3) progressive research and information center dedicated to comprehensively monitoring, analyzing, and correcting misinformation in the U.S. media.", now that would be worth reading. Member Since: July 30, 2010 Posts: 0 Comments: 491

298. SQUAWK 5:05 PM GMT on December 15, 2010
Quoting RipplinH2O: You miss my point: Media Matters isn't watchdogging "journalist(s) doing sketchy things", they watch the conservative press. Now, had they left out the word "conservative" in their mission statement and stated "Media Matters for America is a Web-based, not-for-profit, 501(c)(3) progressive research and information center dedicated to comprehensively monitoring, analyzing, and correcting misinformation in the U.S. media.", now that would be worth reading. Spot On!!!!! Member Since: December 9, 2008 Posts: 0 Comments: 2497

299. Neapolitan 5:07 PM GMT on December 15, 2010
Quoting RipplinH2O: You miss my point: Media Matters isn't watchdogging "journalist(s) doing sketchy things", they watch the conservative press. Now, had they left out the word "conservative" in their mission statement and stated "Media Matters for America is a Web-based, not-for-profit, 501(c)(3) progressive research and information center dedicated to comprehensively monitoring, analyzing, and correcting misinformation in the U.S. media.", now that would be worth reading. It seems you miss my point, so I'll repeat it: it's not the messenger, but the message. Any group that challenges any media--right, left, or middle--in an effort to keep them honest, and that does so in an honest way, is perfectly alright by me. Member Since: November 8, 2009 Posts: 4 Comments: 11153

300. RipplinH2O 5:07 PM GMT on December 15, 2010
@297. I don't know that they have posted anything dishonest. Why? Member Since: July 30, 2010 Posts: 0 Comments: 491

301. RipplinH2O 5:10 PM GMT on December 15, 2010
Any group that challenges ONLY media on the right, as professed publicly in their mission statement, is NOT doing so in an honest way. Bias does not counter bias, it only adds to the pile... Member Since: July 30, 2010 Posts: 0 Comments: 491

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