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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52. Dakster 10:21 PM GMT on December 14, 2010
Wow. Hotter in Maine than in Miami... The next thing that will happen is the Dolphins will win the Superbowl. Oh wait.. That is when Hell freezes over... Member Since: March 10, 2006 Posts: 0 Comments: 4942

53. DDR 10:22 PM GMT on December 14, 2010
Just 5 mm of rain here today(Trinidad),expecting more tomorrow,closing in on 4000 mm for the year. 154 inches since May 14th. Member Since: April 27, 2007 Posts: 13 Comments: 1475

56. weatherbro 10:27 PM GMT on December 14, 2010
the dewpoint is -2 degrees F right now in Orlando. I think tonight will be colder then last night. Member Since: May 26, 2007 Posts: 47 Comments: 1155

58. TampaFLUSA 10:29 PM GMT on December 14, 2010
Quoting DoverWxwatchter: I looked back through the freezes of 1983 and 1985 and the dewpoint was lower today than in either outbreak at Tampa. During those, the dew point fell to 3. Today it hit zero. Also, the water temp off of Clearwater Beach is 47! Member Since: June 21, 2007 Posts: 10 Comments: 1656

65. Seastep 10:47 PM GMT on December 14, 2010
Quoting Neapolitan: Minnemike has asked you several times why you continue to focus on the 1998 outlier (for NOAA; NASA says 2005 was pretty much equal heat-wise to 1998, while 2010 will likely be warmer than either, or very close to it). Until you answer him, I'm inclined to hold my response. Minnemike has done an excellent job of explaining the fallacy of trying to base a scientific case--any case--on data outliers, so it would be interesting to hear your take on why you insist on doing so. Every--and I do mean every--valid and verifiable measurement shows that the planet is warming, and more rapidly than predicted. The folks who scoff at the AGW theory are going to need to do much more to convince me and millions of others than simply saying, "Well, it's not as warm now as it was two weeks ago, so clearly the theory is wrong!" 1998 is not an outlier. It was a step/jump and now the new "normal" if you will. I focus on it because it shows an apparent pattern that I believe will hold. Temps were flat prior, then a jump, then flat again from 1998 forward. Time will tell if it holds. For it to be an outlier, temps would have had to gone back down to pre-1998 levels, but they have not. Again, 1998-2009 is flat in general. As was 1979-1997. Really no need for debate about it. The data will tell. Not trying to convince anyone of anything. Just pointing out a pattern that I see. So far, it is holding through 2009, and will through 2010. We'll see how 2011, 2012, etc. turn out. Again, just an obs. Some may find it significant and/or interesting. Some may not. As for the GISS/NASA data, I mentioned earlier I will plot that for you. Still flat for 1998 forward, just that the "step" is higher. But, no matter. I use the better technology of Sat data with the greater spacial coverage. How much of the actual earth does the GISS cover with actual readings? Have tried to find it, but to no avail. Haven't looked all that hard, though. A map would be perfect. I believe the Sat data is 25km resolution of the entire planet. That resolution is exactly why it is better. You can argue that it isn't, but that's a tough sell. Higher resolution is better. Maybe why the same pattern hasn't been identified yet. Resolution wasn't there prior to 1979. As for your "every" comment, did I ever say the planet has not warmed? Nope. Quite the opposite. I clearly showed that starting in 1998, the planet is warmer than it was from 1979-1997. Again, you are free to pay no attention to it and to rely on the GISS data set. And, again, I'll plot the GISS data for you for 1998-2010 when I get home. Member Since: September 9, 2008 Posts: 6 Comments: 3406

67. Seastep 10:50 PM GMT on December 14, 2010
Quoting McBill: I can't help but thinking that if your analysis of temperature trends relies on using a single year for a point of reference - an outlier year at that - then your analysis is pretty much crap. We're talking climate change here, not weather change. Personally, I think plots of annual average temperatures are too fine grained if you want to talk about climate - sort of like the trees that obscure the view of the forest. I'm much more inclined to consider decadal temperature averages: The data for the graph comes from here. I'll also add that if you would like another take on the suitability of satellite measurements for temperature changes you can read what Jeff Masters has to say: Warmest January on record for the lower atmosphere Just so you are aware, that graph in Doc's post was changed. There was a correction to the data. The +0.72C was revised to +0.64. March was actually higher at +0.66C. OK out the door to head home. Member Since: September 9, 2008 Posts: 6 Comments: 3406

68. Neapolitan 10:55 PM GMT on December 14, 2010
Quoting Dakster: Hasn't the Earth at one point in its history been hotter than it is right now? When? and What was going on then? Yes, it's been hotter. But remember, it's not so much that it's been hotter (or colder) in the past; it's how fast the current heating has been and is taking place. With the exception of catastrophic and cataclysmic events such as large asteroid strikes and the like, the planet has never experienced such a rapid and drastic temperature change. And since civilization as we know it wasn't around for any of the previous changes, it's not at all certain how--or even whether--our population of 6,887,000,000 (and counting) will be able to cope. Member Since: November 8, 2009 Posts: 4 Comments: 11169

71. KEEPEROFTHEGATE (Mod) 11:02 PM GMT on December 14, 2010
Member Since: July 15, 2006 Posts: 144 Comments: 40651

75. EnergyMoron 11:09 PM GMT on December 14, 2010
Quoting JFLORIDA: That is the blog I needed to see. Thanks, it puts thing is clearer perspective. Unlike most Florida freezes these last few have involved a significant amount of wind and real temperatures are trending significantly warmer than projected. Although it "feels" colder. That is important in agriculture. Ditto. Any idea anybody on why? I myself do use these forecasts on when to plant and in general they have been very good... except this time. Member Since: December 8, 2009 Posts: 0 Comments: 3

76. KEEPEROFTHEGATE (Mod) 11:11 PM GMT on December 14, 2010
Quoting DoverWxwatchter: It will just be the same thing. 5 years from now, the deniers will just say "but their's been no global warming since 2010!" And anyway, 2005 was hotter than 1998. So the whole "but the world stopped warming in 1998" mantra is false. in five years we will be in a full climate shift which by the way has begun almost six years now as we approach 2015 2020 the arctic ice in summer will be pretty much be gone and a full climate shift will have taken place Member Since: July 15, 2006 Posts: 144 Comments: 40651

77. Orcasystems 11:13 PM GMT on December 14, 2010
Special Notice to Floridians.... Make sure you have anti Freeze in your car radiator... I "think" one of our members did not, and right now they (she) is trying to figure out why her vehicle over heated 5 minutes after she left the house. Member Since: October 1, 2007 Posts: 77 Comments: 26077

79. KEEPEROFTHEGATE (Mod) 11:16 PM GMT on December 14, 2010
Quoting Orcasystems: Special Notice to Floridians.... Make sure you have anti Freeze in your car radiator... I "think" one of our members did not, and right now they (she) is trying to figure out why her vehicle over heated 5 minutes after she left the house. because it was a block of ice which is now a hunk of junk till its fixed anyway Member Since: July 15, 2006 Posts: 144 Comments: 40651

81. EnergyMoron 11:31 PM GMT on December 14, 2010
Quoting KEEPEROFTHEGATE: in five years we will be in a full climate shift which by the way has begun almost six years now as we approach 2015 2020 the arctic ice in summer will be pretty much be gone and a full climate shift will have taken place I think you are correct on this... when this happens there will be the immediate conversions occur as when the ozone hole was discovered. However, with CFC's, there is a rather disturbing article from a Yale prof that came out today about CFC's and European cap-and-trade Yale work on cap and trade The gist of it is that most of the EU carbon money (about a billion dollars) is going to China to destroy CFC's (at about 10x the price) that they manfacture (some of which make it onto the black market anyway). Energy tax needed. Anyway, from Gore's list himself Gore's Repower List I am not a Gore fan. But his list is at least a good start. Renewables will take about 30 years in a market cycle so forget that for right now (it is going as fast as it can be expected). But... As a conservative there is nothing conservative about wasting energy. America wastes 1/2 of the energy in their homes, about $1,500 per year on average. We not only need to worry about government waste but our own personal waste. Stop all waste. Second, Goldman-Sachs (ya I know and am not a fan of them either) has recently reported that the global oil supply/demand picture has been running a 600,000 barrel per day deficit. Come on. Mass transit. Flex hours. Stop spending this money on roads. I am not a fan of the smart grid given what I have seen (have very low energy use house, solar, what do you want?) and don't think it will make much difference. When you go into the utility companies statements anyway they talk about 2 to 3 percent anyway. Ugh on that. Efficiency and transport are things that should be argued now. Member Since: December 8, 2009 Posts: 0 Comments: 3

83. Orcasystems 11:34 PM GMT on December 14, 2010
Quoting DoverWxwatchter: Better to have a garage. Better to move up North where its warm :) Member Since: October 1, 2007 Posts: 77 Comments: 26077

85. Neapolitan 11:46 PM GMT on December 14, 2010
Quoting Seastep: 1998 is not an outlier. It was a step/jump and now the new "normal" if you will. I focus on it because it shows an apparent pattern that I believe will hold. Temps were flat prior, then a jump, then flat again from 1998 forward. 1998 was an outlier, even by your own definition. Now, you can keep claiming that the global temperature has flatlined since then, but there are reams of valid and verified data that say otherwise. 1998 was a hot year, yes. 2003 was only slightly cooler. 2005 was as warm as 1998 (and actually warmer according to NASA), and 2010 has been the warmest meteorological year ever recorded. How anyone can look at those numbers and try to claim that it's not getting warmer is completely beyond me. In short, the 1970s were warmer than the 1960s; the 1980s were warmer than the 1970s; the 1990s were warmer than the 1980s; the 2000s were warmer than the 1990s, and--if this year is any indication (and it is), the 2010s will be warmer than the 2000s were. (And I'll go out on a very short limb here: unless things change drastically, the 2020s will be substantially warmer than the 2010s.) Click for larger image: Member Since: November 8, 2009 Posts: 4 Comments: 11169

86. WxLogic 11:48 PM GMT on December 14, 2010
Good evening... tonight will be trouble. With light WND and low DWPT currently in the 7F... I see my location in Central FL definitely being in the lower 20s. @7PM yesterday I was at this time at 39F with brisk WNDs... now I'm at 37.8F and is only 6:47PM. Member Since: August 14, 2008 Posts: 4 Comments: 4667

88. WxLogic 11:52 PM GMT on December 14, 2010
Quoting JFLORIDA: Its dead still tonight in north central Fla and we are forecast to hit 16. There will be significant crop damage in s fla tomorrow unless wind or clouds move in. I take you're in far N CFL to get the ~16F. Currently no CLD in site: Winds are light upstream... a mainly 5MPH to 10MPH is you're lucky on non WND protected areas: Member Since: August 14, 2008 Posts: 4 Comments: 4667

89. WxLogic 11:55 PM GMT on December 14, 2010
Quoting JFLORIDA: I think its going to be FAR worse than last night. In my opinion it will be worst... unless the High pressure moves quicker offshore and brings modified maritime airmass into our area which I unfortunately don't see happening quite just yet. Member Since: August 14, 2008 Posts: 4 Comments: 4667

90. PensacolaDoug 11:55 PM GMT on December 14, 2010
Quoting Dakster: Wow. Hotter in Maine than in Miami... The next thing that will happen is the Dolphins will win the Superbowl. Oh wait.. That is when Hell freezes over... Saints won the Super Bowl last year. Hell has already frozen over at least once for sure! Member Since: July 25, 2006 Posts: 0 Comments: 4828

91. RipplinH2O 11:56 PM GMT on December 14, 2010
@81: The problem with listing Al Gore as a source is the issue with the prime question: did he do Inconvenient Truth and then set himself up to make millions from the effect or did he set himself up to make the millions then create the effect? It's a given, i.e. congressional testimony, that he is set up to make the millions, just a question of chicken and egg... Member Since: July 30, 2010 Posts: 0 Comments: 491

96. EnergyMoron 12:18 AM GMT on December 15, 2010
Quoting RipplinH2O: @81: The problem with listing Al Gore as a source is the issue with the prime question: did he do Inconvenient Truth and then set himself up to make millions from the effect or did he set himself up to make the millions then create the effect? It's a given, i.e. congressional testimony, that he is set up to make the millions, just a question of chicken and egg... I actually can appreciate that sentiment BUT that doesn't negate the fact that oil supply is less than demand right now NOR the fact that the Chinese are aiming to double their efficiency. And looking forward to their resource strapped future they are ramping up renewables. My smart meter is a rip off (Gore is heavily invested in those). Actually has increased what I and others pay in electric bills (unlike Gore's hype). See Link I have an okay plan (ain't perfect) but it turned out that efficiency improvements I have made to reduce 18% base use... some of those... benefit the retail electric provider. These smart meters if not structured properly can actually give disincentives to efficiency improvements. But what do you expect from something mandated by the government? 2005 energy bill to be precise, but it turns out that the smart meter provisions were by a coal state dem. Member Since: December 8, 2009 Posts: 0 Comments: 3

97. RipplinH2O 12:19 AM GMT on December 15, 2010
@95. Nope, congressional testimony. I don't have it handy, but look for it on U-Tube. The Senator currently in his old seat asked him during sworn testimony about his interest in a certain company. His response is entertaining no matter where you stand on the issue. If a link doesn't show up shortly by someone else, I'll find it and post it...again. Member Since: July 30, 2010 Posts: 0 Comments: 491

98. RipplinH2O 12:25 AM GMT on December 15, 2010
EM, concur with all but just pointing out that the good ex-VP ain't the best poster child for the pro-AGW crowd. He's got the carbon footprint of Guatamala and is set to profit large if mandates are legislated... Member Since: July 30, 2010 Posts: 0 Comments: 491

99. EnergyMoron 12:26 AM GMT on December 15, 2010
Quoting RipplinH2O: EM, concur with all but just pointing out that the good ex-VP ain't the best poster child for the pro-AGW crowd. He's got the carbon footprint of Guatamala and is set to profit large if mandates are legislated... I definitely agree with that. I just wanted to point out, since a lot of folks do think he is great, that some of his stuff makes sense. But when somebody installs solar, gets a smart meter, and then gets nothing for generated electricity, that is wrong. Dead wrong. Member Since: December 8, 2009 Posts: 0 Comments: 3

101. severstorm 12:31 AM GMT on December 15, 2010
Evening all,My dewpoint is at 10.5 The temp has dropped 6 degrees in the last hour. Going down to 20 tonight. Member Since: November 25, 2007 Posts: 0 Comments: 916

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