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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396. CybrTeddy
9:29 PM GMT on January 10, 2007
hmm if u wanna see that glowing flyin space Rock aka Comet, Look out side at Dust and look above the sun, or glow of the sun and go up u will see what u will think is a Planet but its a coment.
Member Since: July 8, 2005 Posts: 259 Comments: 24602
392. weatherboykris
8:38 PM GMT on January 10, 2007
Link
Member Since: December 9, 2006 Posts: 125 Comments: 11346
391. txag91met
8:33 PM GMT on January 10, 2007
LouisC:

They won't be able to take most of the urban effect out...too many stations have it. But at least new data set should be better for next year:


An improved data set being developed at NCDC and scheduled for release in 2007 incorporates recent scientific advances that better address uncertainties in the instrumental record. Small changes in annual average temperatures will affect individual rankings. Although undergoing final testing and development, this new data set also shows 2006 and 1998 to be the two warmest years on record for the contiguous U.S., but with 2006 slightly cooler than 1998.
Member Since: January 30, 2005 Posts: 6 Comments: 751
390. weatherboykris
8:30 PM GMT on January 10, 2007
I didn't.Besides Fort Myers and Naples,SW Florida is relatively unpopulated.
Member Since: December 9, 2006 Posts: 125 Comments: 11346
389. ErikMia
8:24 PM GMT on January 10, 2007
Public Information Statement

Statement as of 12:38 PM EST on January 10, 2007

... Shaking this morning probably caused by sonic boom...

The shaking of homes and buildings felt by many people this
morning across southwest Florida was probably caused by a sonic boom
from military aircraft.

The Boca Chica Naval Air Station near Key West has confirmed that
there were supersonic capable aircraft in the area this morning.

This morning's atmospheric conditions were favorable for a sonic boom
to propagate over large distances from a source and be felt close to
the ground... due to the presence of a cold and dry airmass just above
the ground. This resulted in the presence of a very stable air layer
at low levels which was conducive for the propagation of sound waves
over long distances.

Did anyone feel this???
388. Thunderstorm2
8:16 PM GMT on January 10, 2007
hi everyone
Member Since: December 22, 2006 Posts: 130 Comments: 7608
387. weatherboykris
8:15 PM GMT on January 10, 2007
hi H23
Member Since: December 9, 2006 Posts: 125 Comments: 11346
386. weatherboykris
8:14 PM GMT on January 10, 2007
LOL,just kidding
Member Since: December 9, 2006 Posts: 125 Comments: 11346
385. weatherboykris
8:14 PM GMT on January 10, 2007
CB beware,I'm back
Member Since: December 9, 2006 Posts: 125 Comments: 11346
384. LouisC
8:11 PM GMT on January 10, 2007
Regarding the Urban Heat Island effect, in the article on its Web site, NOAA explains: "These values were calculated using a network of more than 1,200 U.S. Historical Climatology Network stations. These data, primarily from rural stations, have been adjusted to remove artificial effects resulting from factors such as urbanization and station and instrument changes, which occurred during the period of record."
383. hurricane23
8:10 PM GMT on January 10, 2007
Hey weatherboykris!
Member Since: May 14, 2006 Posts: 8 Comments: 13841
382. weatherboykris
8:09 PM GMT on January 10, 2007
RIP El Nino.Look at my blog archive,I said it a month ago.
Member Since: December 9, 2006 Posts: 125 Comments: 11346
381. weatherboykris
8:08 PM GMT on January 10, 2007
hi
Member Since: December 9, 2006 Posts: 125 Comments: 11346
380. hurricane23
7:43 PM GMT on January 10, 2007
This map is also useful at Unisys Weather.

Free Image Hosting at www.ImageShack.us

Member Since: May 14, 2006 Posts: 8 Comments: 13841
379. txag91met
7:38 PM GMT on January 10, 2007
Actual surface measurements are contaminated by the Urban Heat Island effect. There are so many stations used by NCDC that have this effect. Look at Dallas/Fort Worth: Since 1950 the population has increase from roughly 855000 to over 4 million (burbs included). Cement and asphalt have increased surface temperatures. DFW just had their warmest year ever (2006). Waco (80 miles South) did not.
Member Since: January 30, 2005 Posts: 6 Comments: 751
378. Caffinehog
7:35 PM GMT on January 10, 2007
Cyclone, let's say that you wanted to cool a swath of ocean 110Km wided by 40km. Let's say you cooled the top 25m. Let's say you wanted to do it in 48 hours, and let's say you need to replace 20% of the upper layers of the water to do it. (Which I've already established to be correct.)

Your tunnels would have to bring up a combined 3,360,000 gallons of water per second. (or about 12,700,000 liters per second.)
If we assume your tunnels were 5m across, and if we assume that water was flowing out of them at the same speed as the gulf stream, with nothing slowing it down, then you would need at least 3,230 of these tunnels in your little swath of ocean.

Not to mention that you would be releasing the energy of approximately 250 hiroshima bombs into the depths. (I know you'll say, "but you're bringing cold water to the surface, not bringing hot down!" Well, the water you displace has to go somewhere!)
Member Since: June 5, 2003 Posts: 0 Comments: 40
374. Tazmanian
7:29 PM GMT on January 10, 2007
and the olny way to keep a eye on BERMUDA HIGH is by looking at this map

lol
Member Since: May 21, 2006 Posts: 5091 Comments: 115505
373. DewyCheatum
7:15 PM GMT on January 10, 2007
gee, I come back after a hiatus to find discussions on....TUNNELS. Enough, already.
Member Since: October 18, 2005 Posts: 1 Comments: 50
372. hurricane23
7:15 PM GMT on January 10, 2007
882MB its impossible to know what kind of pattern will be in place come time for hurricane season but the best thing we all can do is just be ready come june1.I know i will.
Member Since: May 14, 2006 Posts: 8 Comments: 13841
370. hurricane23
7:09 PM GMT on January 10, 2007
Yea CB it will be either Thursday or Friday.
Member Since: May 14, 2006 Posts: 8 Comments: 13841
366. Patrap
7:03 PM GMT on January 10, 2007
One HOT night
Member Since: July 3, 2005 Posts: 429 Comments: 130486
365. 882MB
7:03 PM GMT on January 10, 2007
Is there any model that shows the STRENGTH OF THE BERMUDA HIGH DURING HURRICANE SEASON!
Member Since: September 29, 2006 Posts: 0 Comments: 447
364. hurricane23
6:58 PM GMT on January 10, 2007
Dr.Masters will be discussing the fadeing El.Nino on his blog thursday or Friday.Just wanted to give everyone a heads up.
Member Since: May 14, 2006 Posts: 8 Comments: 13841
363. ricderr
6:55 PM GMT on January 10, 2007
ok.....again i say...beware the models...and since i'm not an expert...here's what the austrailian experts say about the models and their forecasting abilities....also.note the months being referenced to..and the comments the austrailian experts make...


the March to June period is known as the "predictability barrier" and model skill is at its lowest predicting across this span of months. Users should therefore exercise caution when interpreting forecasts for the middle of 2007, and are encouraged to view the actual model outputs by following the web links. Frequent updates of the latest observational data with relevant commentary are available on the Bureau's ENSO Wrap-Up page.
Member Since: June 27, 2006 Posts: 676 Comments: 22568
361. hurricane23
6:39 PM GMT on January 10, 2007
If the MJO maintains its intensity as it propagates into the western Pacific, a fall in the SOI, a decrease in the Trade Wind strength and an increase in cloudiness may occur as a result. This may cause temporary strengthening of the El Nio event, but given the recent trends and the predictions from computer models, neutral ENSO conditions are expected to return during the southern autumn.
Member Since: May 14, 2006 Posts: 8 Comments: 13841
360. 882MB
6:37 PM GMT on January 10, 2007
Hey everybody, It all depends on the BERMUDA HIGH, I think were gonna have an active season, but it all depends on the STRENGTH and LOCATION of the BERMUDA HIGH if there is a TROUGH in the EASTERN SEABOARD like last year then we might be lucky, but this usually DOESNT HAPPEN, usually if you have a trough in the east one hurricane season then the next hurricane season will have a stronger then normal bermuda high!
Member Since: September 29, 2006 Posts: 0 Comments: 447
359. ricderr
6:36 PM GMT on January 10, 2007
I can tell ya where to put the tunnels..But its just another tunnel..LOL!



can i hold him down for you???...please please
Member Since: June 27, 2006 Posts: 676 Comments: 22568
358. Patrap
6:36 PM GMT on January 10, 2007
Ahhh..Kinda miss the Cold War..things were more defined..not so Hazy as todays mess.
Member Since: July 3, 2005 Posts: 429 Comments: 130486
354. ricderr
6:32 PM GMT on January 10, 2007
just a little note.....before you jump on the el nino is dead bandwagon...not saying it is or isnt..but...before you base it on a forecast model..go back to 2006..and look at how the models did against actual conditions..you'll note that many did not predict an el nino event.....2nd...if you decide that the models are good or even helpful..note that the models are showing el nino to weaken in the short term...but then strengthen again
Member Since: June 27, 2006 Posts: 676 Comments: 22568
353. anvilhead
6:32 PM GMT on January 10, 2007
all changed Michael
Member Since: September 14, 2006 Posts: 128 Comments: 5257
352. Patrap
6:30 PM GMT on January 10, 2007
40,000 thermonuclear weapons May beg to differ on the Destruction thing.
Member Since: July 3, 2005 Posts: 429 Comments: 130486
350. grimmdogg23
6:17 PM GMT on January 10, 2007
Global Warming is a political stance to stand on. There are facts to support Global Warming and to discredit it. People usually fall on either side by their political aspects. I personally do not believe we could do anything to destroy the earth. However, I am all for cheaper and cleaner energy. I am also for keeping the earth free from litter.
Member Since: Posts: Comments:
349. txag91met
6:21 PM GMT on January 10, 2007
Satellite data does not support 2006 as warmest ever:

1998 was still warmest ever for the USA after the 1997-1998 El Nino.
The rest is growing urbanization.
1930s was still warmer if you ask me.

Global satellite temperatures below.

not there
Member Since: January 30, 2005 Posts: 6 Comments: 751

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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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