A white Christmas will be a U.S. rarity in 2011; November the globe's 12th warmest
A white Christmas will be a rarity across most of the U.S. this year, as December temperatures have been more typical of November, and very little snow has fallen. Large portions of the eastern half of the country have been more than 4°F above average so far in December, with temperatures averaging 8°F above average over portions of North Dakota.This is quite a switch from the previous two winters, which were both much colder and snowier than average. All three winters featured La Niña conditions in the Eastern Pacific Ocean, so that cannot explain the difference. A key reason for the December warmth this year and the cold and snowy Decembers of 2010 and 2009 is a weather pattern known as the Arctic Oscillation.
Figure 1. Departure of temperature from average over the 30-day period ending on December 22, 2011. Image credit: NOAA/CPC.
Figure 2. Top: snow depth measured in the U.S. on December 22, 2011, after a month with a strong positive phase of the Arctic Oscillation (AO). Bottom: Snow depth measured in the U.S. on December 22, 2010, after a month with a strong negative phase of the Arctic Oscillation (AO). Image credit: NOAA/NOHRSC.
The Arctic Oscillation and its influence on winter weather
The Arctic Oscillation (AO), and its close cousin, the North Atlantic Oscillation (NAO), are climate patterns in the Northern Hemisphere defined by 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 AO and NAO control 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 AO/NAO) leads to increased westerly winds and mild winter in the U.S. and Western Europe. Positive AO/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 AO/NAO), westerly winds are suppressed, allowing Arctic air to spill southwards into eastern North America more readily. Negative AO/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 and AO since record keeping began in 1865; a very extreme AO/NAO also developed during the winter of 2010 - 2011. But this year, the pattern has flipped. The AO has been almost as strong, but in the opposite sense--a positive AO, leading to very warm conditions over the U.S. Unfortunately, the AO is difficult to predict more than a week or two and advance, and we don't understand why the AO can vary so much from winter to winter. The latest predictions from the ECMWF and GFS models show this positive AO pattern continuing for at least the next ten days. Real winter conditions won't arrive in the U.S. until the first week of January, at the earliest. Between now and the end of 2011, the only major winter storm the GFS model expects in the U.S. will be in the Pacific Northwest, on December 30 - 31.
This week, NOAA's ClimateWatch Magazine posted an excellent tutorial on the Arctic Oscillation and how it is affecting our winter weather this year.
Figure 3. The departure of temperature from average in Centigrade during the November - December - January period during various phases of the Arctic Oscillation (AO). Positive AO conditions lead to warm winters in the U.S., while negative AO conditions lead to cold winters. Image credit: NOAA/CPC.
November 2011: Earth's 12th warmest on record
November 2011 was the globe's 12th warmest November on record, according to the National Oceanic and Atmospheric Administration's National Climatic Data Center (NCDC). November 2011 global land temperatures were the 16th warmest on record, and ocean temperatures were the 12th warmest on record. Global satellite-measured temperatures for the lowest 8 km of the atmosphere near average, the 20th or 11th warmest in the 34-year record, according to Remote Sensing Systems and the University of Alabama Huntsville (UAH). Wunderground's weather historian, Christopher C. Burt, has a comprehensive post on the November 2011 Global Weather Extremes Summary.
Figure 4. Departure of temperature from average for November 2011. Image credit: National Climatic Data Center (NCDC).
A warm November for the U.S.
In the contiguous U.S., November ranked as the 25th warmest November in the 117-year record. Thirteen states in the Northeast and Upper Midwest recorded a top-ten warmest November, and no states had a top-ten coldest November. Eight states had a top-ten wettest November--Indiana, Ohio, Missouri,Illinois, Kentucky, Tennessee, Arkansas, and Oklahoma. One state had a top-ten driest month, Minnesota. Texas had its 39th driest November on record, keeping 76% of Texas under extreme to exceptional drought as of December 13, according to the U.S. Drought Monitor.
A weak La Niña continues
A borderline weak/moderate La Niña event continues in the equatorial Pacific, where sea surface temperatures were approximately 1.0°C below average during the first half of December. The impacts of a La Niña on U.S. weather are well-defined. It is likely that the drought in the South, especially Texas, will continue, along with above average temperatures. The Northwest can expect cooler than average temperatures, as well as the potential for another winter with a heavy snowpack across the western United States.
Arctic sea ice extent third lowest on record
Arctic sea ice extent was at its third lowest on record in November, behind 2006 and 2010, according to the National Snow and Ice Data Center. Sea ice records date back to 1979.
Donations sought for the East Africa famine
Weather Underground has partnered with the International Rescue Committee (IRC) to help the Horn of Africa region during the ongoing famine. With the help of the Weather Underground community, we hope to raise $10,000 that will go toward helping the refugees survive the crisis. Weather Underground will match the community's donation dollar-for-dollar up to $10,000 for a total donation of $20,000. Please visit the East Africa famine donation page to help out. Ninety cents of every dollar donated goes directly to the people in need.
Posts looking back at the remarkable weather events of 2011
Deadliest weather disaster of 2011: the East African drought
Tropical Storm Lee's flood in Binghamton: was global warming the final straw?
Wettest year on record in Philadelphia; 2011 sets record for wet/dry extremes in U.S.
Hurricane Irene: New York City dodges a potential storm surge mega-disaster
This will be my last post until Tuesday. Have a great holiday, everyone!
Jeff Masters
Reader Comments
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ESPANOL!!!!
They are now 364 Giorni Day's until the 2012 Winter Solstice.
Enjoy your Thursday evening.
Oh and, Feliz Navidad
I just started taking an evening Spanish class....give me a few weeks and maybe I'll know something ;-)
365leap year buddy
tengo una clasede espanol ppara la escuela, es horible, no me gusta, no me gusta, no me gusta!!!
No you're both wrong, it's September 10...
hey, Press,you and I are in dat un.
The DeQuincy tornado was the 1,881st U.S. tornado reported in 2011, but the first confirmed during the month of December, 2011
More on the Dec 20, 2011 Dequincy tornado at the addy above. Pics and stuff. A link to it can be found on the NWS Lake Charles, La. page.
Said I, to the Bishop of Charleston: "The Diocese oughta offer Spanish lessons free of charge to people active in parishes with high numbers of Spanish speaking parishioners...in order that we may build stronger relationships."
Said he to me: "That's a fine damned idea! And I appoint you in charge of making that happen! And be sure to enroll yourself as the first student!"
So...I'm sorta stuck....
I've garnered nuff Fresca for a Few Years on the New Planet.
The cyclones there are Much Bigger than here definitely they say.
yea....but ....Who writes the weather blog?
Good luck its boring or that could be my teacher i dont know, i hate when people screw you over like that
Funny, dat still comes outta Boca/Jax for some reason,,
trolls and LOTS OF CROW
Yuck! I just saw that. Not a pretty picture.
Percentage of Counties/Parishes covered by Drought
Yes, 1970 was 41 years ago. The baseline is for the first 30 years.
Those are images from space, hydrus. Not weather satellites but, nice images regardless. It is kinda like taking your first look in a mirror. Sadly, for me, my first look was much better than my last look. sigh .... who IS that old man?!?!?!
So is your Spanish! j/k
From the TV transmission around 56:33 GET. Earth was reported to be at a distance of around 177 000 nautical miles at the time.
Houston comments on the ITCZ at 3:15
Who remembers this? We thought we were hot stuff back then.
So far, nothing that seems to make it easier to forecast next season's NS total...
[g]
Just imagine yourself being interviewed for a company doing business in LAmerica and getting the position.... because of your ability to comunicate.... Learn to master Spanish.... Ahh, Include also Mandarin....
One can check the archives,, as Apollo 11 Flew from July 16-24 1969.
Way to go and i thought it was flat.
I forgot to take my Prozac. Leave me alone! LOL ... OK, I'm better noooooow. .... OH! Hi, hydrus! .. When did you get here?
They are nice images. Our first look back at our planet. Truly, an amazing view. Before this we could see no more of the planet than from what we view from an airplane.
How long has this been active?
The Osmonds?
Do you remember this one? ... I only ask because I know what old timers disease is like.
Link
Hello, Grothar! ... Yes, I am fine now. I found the Prozac!
One thing for certain, hydrus. Earth is certainly one of a kind and a crown jewel it is.
Added -
I also see an EPAC system there. Looking at the weather patterns around it, it is going to hit ... wait for it .... FLORIDA!
Give me a break. The Prozac has not taken full effect yet. LOL .... Any minute now. fingers crossed
Pic is from the crew of Apollo 17, better known as AS17-148-22727 by NASA, or the ''Blue Marble'',
Specs on the cyclone,
Crossed Tamilnadu coast close to and north of Cudalore at 2330 UTC on 5th December and was within 50 km WNW of Cuddalore at 0300 UTCon December 6. Maximum wind speed recorded at Cuddalore was 111 KMPH to 148 KMPH (60-80) between 2230 UTC of 5th & 0230 UTC of 6th.80 People killed and 30,000 people rendered homeless in Madras due to flood.Total loss Rs. 40 crores.
Link
7 years. You mean all this time you didn't know you liked you and who didn't?
Never heard of them!
my bad, thought they were referring to da video from Neil and 11.
I stop at french...
Better off not knowing :) You sure it has not been around just 1 dog-age year?
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