2006: warmest year on record in the U.S.

By: Dr. Jeff Masters , 9:18 PM GMT on January 09, 2007

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The United States recorded its warmest year ever in 2006, according to today's report issued by the National Climatic Data Center (NCDC). The 2006 annual average temperature was 55�F, 2.2�F (1.2�C) above the 20th Century mean and 0.07�F (0.04�C) warmer than the previous warmest year, 1998. The NCDC had estimated that 2006 would be the 3rd warmest year in U.S. history last month, but an unusually warm December pushed 2006 to the top. It was the warmest December on record in the Northeast U.S., and the 4th warmest December for the country as a whole. Only 1939, 1957, and 1933 had warmer Decembers. However, the statistics partially hide the extraordinary warmth that began on December 10 and continued until January 6, when New York City tied their all-time record January high temperature of 72�. During the month ending January 6, the Northeast was 14 �F above average, and the U.S. as a whole was 7� above average.



No cause for alarm?
"No cause for alarm. Enjoy it while you have it," said Mike Halpert, head of forecast operations at the National Oceanic & Atmospheric Administration's Climate Prediction Center, in a story run by CNN just before New York City's record warmth. The story continued, "The weather is prone to short-term fluctuations, and forecasters said the mild winter does not necessarily mean global warming is upon us. In fact, the Plains have been hit by back-to-back blizzards in the past two weeks." True, the weather across most of the U.S. has finally cooled off this week, and the rest of January should have near average temperatures. And I agree that one warm month of winter in one country in its warmest year in 112 years of record keeping is not evidence of global warming, particularly when there is a moderate El Nino episode going on. An El Nino can lead to significantly warmer winters in the U.S.--exceptional December warmth has also occurred in 1877, 1939, and 1957, all of which were moderate or strong El Nino years. I've plotted up a comparison of temperatures in December of 1957 vs 2006 (Figure 1), and one can see that the unusual warmth of December 2006 does have historical precedent. Taking a look at average U.S. December temperatures for all years in the historical record (Figure 2), we see that these temperatures do show quite a bit of noise, and there is no evidence of dramatic warming in the past 30 years.


Figure 1. Comparison of the departure of average temperature from normal for December 1957 (the the second warmest December on record in the U.S.) and December 2006. Image credit: NOAA.

Figure 2. Average December temperatures for the U.S. from 1895 to 2006. Image credit: National Climatic Data Center.

Rolling thirteens with the weather dice
Take a look at the trend December temperatures in Figure 2. It shows that the average temperature has warmed a little more than 1� F in the past century. It may not seem like much, but that is enough to significantly load the dice in favor of warmer winters. Six of the ten warmest U.S. winters on record have occurred in the past 15 years. Month long spells where winter is seemingly absent--as also occurred in January 2006, the warmest January in U.S. history--have become more common. Keep in mind that the weather of January of 2006--which blew away the previous record for warmest January by a huge margin (2� F)--occurred during a La Nina year, not an El Nino. What concerns me most is that the warming trend is not isolated to the U.S. The 1� F rise in temperatures the past century has occurred world-wide, thanks to global warming, and the temperature increase has been much higher in the Arctic--something the climate models have predicted would occur as a telltale sign of the human-caused addition of greenhouse gases to the atmosphere. In the past, an exceptionally warm winter month in the U.S., like December 1957 (Figure 3), was offset by much cooler weather elsewhere, such as we see in Alaska, Greenland, and northern Siberia. However, December 2006 had no such offsetting cool temperatures--it was more than 1� C above average over almost all the land areas of the Northern Hemisphere north of 40� north latitude (Figure 4). Colorado, whose three blizzards have been widely cited as evidence that winter has been severe elsewhere, still recorded temperatures about 1� C above normal in December 2006.


Figure 3. Global departure of temperature from average for December 1957, the second warmest December on record in the U.S. Note that the exceptionally warm temperatures over the U.S. are offset by much cooler weather elsewhere, such as in Alaska, Greenland, and northern Siberia.

Figure 4. Global departure of temperature from average for December 2006. Note that the almost the entire globe north of 40� north latitude was more than 1� C above average, with large areas more than 6� C (11� F) above average.

All this unusual heat in the northern high latitudes is going to significantly slow down the formation of ice over the Arctic Ocean this winter. Furthermore, the lack of the usual snows across the Arctic may allow the snowpack to melt much earlier than normal in spring, resulting in more record warmth in the Arctic this summer. Arctic sea ice coverage, already down 20% in the past 20 years, is likely to continue to shrink in 2007. As sea ice melts in response to rising temperatures, it creates a positive feedback loop: melting ice means more of the dark ocean is exposed, allowing it to absorb more of the sun's energy, further increasing air temperatures, ocean temperatures, and ice melt. The observed changes in the ice cover (Figure 5) indicate that this feedback is now starting to take hold, and the weather dice will continue to get more loaded towards rolling higher numbers in 2007. I do think we're due for a cold winter next year--part of the warmth of the past two winters is probably due to the normal random fluctuations in the weather, and Nature has been rolling twelves more often than snake eyes of late. However, we're not going to see snake eyes too much more. December's weather in the Northeast U.S. may have been a case of the weather dice coming up thirteen--weather not seen on the planet since before the Ice Age began, 118,000 years ago. The weather dice will start rolling an increasing number of thirteens in coming years, and an ice-free Arctic Ocean in summertime by 2040 is a very real possibility, as indicated by computer modelling studies published in the Journal of Geophysical Research last month. This possibility is cause for alarm, and I, for one, had a lot of trouble enjoying the phenomenally warm weather of the past month here in Michigan.


Figure 5. Percent change in coverage of Arctic sea ice in Decembers from 1979-2006, compared to the 1979-2000 average. The Polar Ice Cap has shrunk by about 15% in December, and 20% in summer, over the past 20 years. Image credit: National Snow and Ice Data Center.

Check out the realclimate.org post on this winter's anomalous warmth.

I'll be back Thursday afternoon or Friday with a look at the status of El Nino. Will it still be around during hurricane season?

Jeff Masters

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649. weatherboykris
9:30 PM GMT on January 11, 2007
You'd have both layers of water (warm and cold) at whatever the average temp between the two was before they interacted.Assuming of course, that the cold water doesn't sink instantly.
Member Since: December 9, 2006 Posts: 125 Comments: 11346
648. weatherboykris
9:27 PM GMT on January 11, 2007
That is exactly what I wanted to happen! I want the cooler water to plummet through the warmer layer below it thus cooling it also as it sinks! This thick layer of warm water probably 300 to 400 feet thick needs to be cooled since it is the fuel for the hurricane!!

You're physics are a little off CB.The cold water wouldn't cool the warm water,the warm water would warm the cold water.
Member Since: December 9, 2006 Posts: 125 Comments: 11346
647. Randrewl
9:26 PM GMT on January 11, 2007
Prolonged Period of Cold and Stormy Weather Appears on the Way

Something for all the Bastardi fans.
Member Since: June 8, 2006 Posts: 114 Comments: 31557
646. weatherboykris
9:23 PM GMT on January 11, 2007
Thanks orion,I meant no offense

Cyclonebuster,Andrew was moving too fast to be significantly affected.By the time it was over the Gulfstream(which you say is about 40 miles wide),it was a category 5 with 160 mph winds.It would've spent only 2 hours over the cooled waters of the Gulfstream,which I'll admit may have weakened it back down from 165 at landfall to 145.All of that,of course, assumes the tunnels would even work.
Member Since: December 9, 2006 Posts: 125 Comments: 11346
643. orionRider
21:20 GMT le 11 janvier 2007
Sorry, my English is not very good. I meant that even ten feet of (cold) water is enough to isolate you from something very warm, like glowing lava. Water is not like metal that conducts heat easily from one molecule to the other.

Caffinehog assumed that the cold water goes to the surface and somehow stays there. Not so, heavy water does not stay above light water. There will be some mix, but most of the cold water will plummet back.
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642. weatherboykris
9:19 PM GMT on January 11, 2007
It would already be too late even if it worked.
Member Since: December 9, 2006 Posts: 125 Comments: 11346
640. weatherboykris
9:11 PM GMT on January 11, 2007
Cyclonebuster,how would your tunnels combat global warming due to greenhouse gases.
Member Since: December 9, 2006 Posts: 125 Comments: 11346
637. weatherboykris
8:38 PM GMT on January 11, 2007
And don't count on propagation to transfer the temp, it won't work. You can swim ten feet from a volcano and still have cold feet.

Um...who swims next to volcanoes.Or more accurately, where can you swim next to a volcano?I agree his ideas are flawed,but that didn't really make much sense.
Member Since: December 9, 2006 Posts: 125 Comments: 11346
636. orionRider
20:34 GMT le 11 janvier 2007
CB, you say: tunnels [...] start drawing cool water from below and mix it with the warm surface water...

I may not know much about meteorology but I know enough about water and there is something I know for a fact: bodies of water of different density don't mix easily. If you pump cold water to the surface it will just sink back to the bottom in no time. It takes a tremendous amount of energy to 'mix' water. And don't count on propagation to transfer the temp, it won't work. You can swim ten feet from a volcano and still have cold feet.
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635. weatherboykris
8:13 PM GMT on January 11, 2007
I'll be back later on.
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634. catastropheadjuster
8:06 PM GMT on January 11, 2007
I'll be back gotta go get my daughter from school.
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633. weatherboykris
8:12 PM GMT on January 11, 2007
I'm buying it STL.Even in 16 days the GFS has the East U.S. in a trough with the 500mb flow coming down from Canada and Alaska.
none
Member Since: December 9, 2006 Posts: 125 Comments: 11346
631. weatherboykris
8:05 PM GMT on January 11, 2007
Sorry catastrophe,but it's getting cold
Member Since: December 9, 2006 Posts: 125 Comments: 11346
628. weatherboykris
8:04 PM GMT on January 11, 2007
I'm sorry,I meant that it wasn't as good as the Hurricane Andrew section in Hurricane Watch.
Member Since: December 9, 2006 Posts: 125 Comments: 11346
627. weatherboykris
8:04 PM GMT on January 11, 2007
I like that book to H23.THe Hurricane Andrew part was good,but not as good as he on in Hurricane Watch
Member Since: December 9, 2006 Posts: 125 Comments: 11346
625. catastropheadjuster
7:58 PM GMT on January 11, 2007
So does anyone think as mild of a winter where having right know that winter will come back with a vengence before it's over with? It shows that here in LA Alabama its gonna be in the high 60's to middle 70's til next week. It would be nice if it would stay like this my husband would be very happy. He hates cold weather.
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624. hurricane23
3:00 PM EST on January 11, 2007
The best book ive ever read is by Bryan Norcross one of my favorite meteorologist the book is called hurricane almanac 2006 its filled with tons off valuable info on the tropics past and present.

Here is a pic of the book...



I highly recommed it to everyone who has a passion for tracking hurricanes.

Bryan Norcross Website
Member Since: May 14, 2006 Posts: 8 Comments: 13626
623. weatherboykris
7:56 PM GMT on January 11, 2007
Yes, Skye.I'm trusting the obs much more than the models at this point.And the obs are indicating we will be much cooler by this time next month.
Member Since: December 9, 2006 Posts: 125 Comments: 11346
621. Skyepony (Mod)
7:29 PM GMT on January 11, 2007
catastropheadjuster~ Yeah, the high has alot to do with what may hit land. So many factors.

The CPC predicts a return to neutral by March-May. Doesn't forcast any farther then that & has low forecast confidence as well. They are probibly as weary of their long term model preformance as we are. Like Michael pointed out the cold spot just below the surface, that's our short term cetainty, beyond that much & it's largely a guess at this point.
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620. weatherboykris
7:42 PM GMT on January 11, 2007
The CFS model mean, shown hereLink
has been calling for anosedive since late December,but that has failed to happen thus far.The models have actually been terrible for the past year or so at predicting El Nino.
Member Since: December 9, 2006 Posts: 125 Comments: 11346
619. catastropheadjuster
7:39 PM GMT on January 11, 2007
I think there's alot of really smart people that come to this site. Last hurricane season I would come on here and read everyday and learn alot. Everyone has there on opinion.
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618. weatherboykris
7:41 PM GMT on January 11, 2007
Hard to say
Member Since: December 9, 2006 Posts: 125 Comments: 11346
617. catastropheadjuster
7:35 PM GMT on January 11, 2007
Well here in Alabama the weather has been really nice.Got up this morning and frost was on the ground but it has warmed up real nice. I guess it's a wait and see with El nino?
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616. weatherboykris
7:37 PM GMT on January 11, 2007
It's not like any of us are proffesional meteorologists.Although I think there are a few college students studying to be meteorologists.
Member Since: December 9, 2006 Posts: 125 Comments: 11346
615. weatherboykris
7:27 PM GMT on January 11, 2007
not at all,take part in what we're talking about.
Member Since: December 9, 2006 Posts: 125 Comments: 11346
614. catastropheadjuster
7:00 PM GMT on January 11, 2007
Weatherboykris thanks for the info and taking time to tell me this stuff. Have a great day. I'll be sitting back reading about what you'll are saying. I hope i didn't impose.
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613. Thunderstorm2
7:07 PM GMT on January 11, 2007
i can't belive that 21,500 more troops are getting sent into iraq
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612. Thunderstorm2
7:04 PM GMT on January 11, 2007
i can't beleive that 21,500 troops are getting sent into iraqi
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611. Patrap
1:02 PM CST on January 11, 2007
Marching on New Orleans City hall..this hour..was live on Tv here..Link
Member Since: July 3, 2005 Posts: 420 Comments: 127543
610. orionRider
19:03 GMT le 11 janvier 2007
Thanks weatherboykris, looks fascinating.

I found another article about the polymer powder. What do you think? It sounds safer than messing with sea currents:

http://environment.newscientist.com/channel/earth/hurricane-season/dn1101
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609. snotly
6:57 PM GMT on January 11, 2007
Link
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608. Thunderstorm2
6:55 PM GMT on January 11, 2007
true
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607. weatherboykris
6:53 PM GMT on January 11, 2007
They'd have to try it on a real storm,and there's 2 problems with that:
(1):in all likelyhood, they don't have the money.
(2)If the thing they tested it on bombed just before landfall and did a ton of damage, they'd need all the money they have for the lawyers.
Member Since: December 9, 2006 Posts: 125 Comments: 11346
606. Thunderstorm2
6:53 PM GMT on January 11, 2007
they can make a hurricane in a bottle
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605. weatherboykris
6:52 PM GMT on January 11, 2007
And just how are they going to bust the myth,snotly?It's not like they can make a hurricane in a swimming pool.LOL
Member Since: December 9, 2006 Posts: 125 Comments: 11346
604. Thunderstorm2
6:51 PM GMT on January 11, 2007
yeah see what they say
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603. snotly
6:49 PM GMT on January 11, 2007
Someone should submit these ideas to Mythbusters
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602. Thunderstorm2
6:48 PM GMT on January 11, 2007
if it does later in the years i'll eat my hat
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601. snotly
6:48 PM GMT on January 11, 2007
CB could use his tunnels and this
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600. snotly
6:49 PM GMT on January 11, 2007
Link
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599. weatherboykris
6:47 PM GMT on January 11, 2007
I don't know.But still, it could happen.
Member Since: December 9, 2006 Posts: 125 Comments: 11346

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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