If global warming is occurring, why was the winter of 2007-2008 so cold and snowy?

By: Dr. Jeff Masters , 1:38 PM GMT on March 14, 2008

The planet was much snowier and warmer than usual during the winter of 2007-2008, according to statistics released today by the National Climatic Data Center. Snow cover extent over the Northern Hemisphere during the period December 2007 - February 2008 was the fourth greatest on record, and was the greatest on record for January. Satellite-derived snow cover records extend back to 1967. Some regions of the Middle East, such as Baghdad, Iraq saw their first snow in living memory, and seasonal snowfall records were broken in Wisconsin and a few places in the Northeastern U.S. Surprisingly, the winter also ranked much above average in temperature--it was the 16th warmest December through February period in the 128-year global record. This puts the winter of 2007-2008 in the warmest 13% of all winters. Temperatures this winter were a bit cooler than recent winters because of an ongoing strong La Niña event in the Eastern Pacific Ocean, which has dramatically cooled the ocean surface waters. By one measure (the surface pressure difference between Darwin and Tahiti), February 2008 was the strongest February La Niña event on record. The last time we had a winter this cool was during 2000-2001, which also happened to be the last time we had a major winter La Niña event.

Figure 1. Departure of temperature from average for the winter of 2007-2008. Image credit: National Climatic Data Center.

A normal winter for the U.S.
December 2007 through February 2008 was about average in the contiguous U.S.--the 54th coolest winter on record in the 113 year period of record. The average temperature was 33.2°F (0.6°C), which was 0.2°F (0.1°C) above the 20th Century mean. It was the 18th wettest December-February in the 1895-2008 record. New York experienced its wettest winter on record, and the states of Colorado, Connecticut, Pennsylvania, and Vermont experienced their second-wettest winter on record. Only the South received below normal levels of precipitation, mostly due to a dry winter in Texas.

All time winter snowfall records have already been set in some portions of the Northeast U.S. and Wisconsin. As of March 12, Madison, WI had accumulated 92 inches of snow, smashing the previous seasonal snowfall record of 76.1 inches (193.3 cm) of snow in the winter of 1978-1979. Two locations in the Northeast have set new winter snowfall records, and more records will fall if an average amount of snow falls in March. By the end of February, new snowfall records for the season-to-date were also set in both Telluride and Aspen, Colorado.

An exceptionally warm winter in Northern Europe and Asia, cold in Central Asia
Northern Asia and northern Europe experienced an exceptionally warm winter, with Sweden and Finland recording their warmest winters ever, and Norway, its second warmest. Conversely, Tajikistan recorded its coldest winter in 30 years, and heavy snows in Kazakhstan caused severe flooding when they melted. Snow storms and cold weather in China this winter killed 129 people and did over $21 billion in damage.

Why did we see a cool winter, if global warming is occurring?
It is important to understand the difference between weather and climate. Climate is what you expect; weather is what you get. What we experience in one particular season or year is "weather". Weather has a large variation from year to year, with cool seasons and years mixed in with warms ones. "Climate" is the weather measured on scales of tens of years or longer. One cool winter or year is not an indication that the climate is cooling back to normal. The climate is warming, and unless we see a series of several years of cool conditions, this year's cool winter merely represents a normal fluctuation of the weather. Relatively cool weather is to be expected globally during a strong La Niña event in the Eastern Pacific Ocean, and relatively warm weather is expected during an El Niño event. We shouldn't expect to see record warmth for the globe unless an El Niño event is occurring.

Why did we see record snows this winter, if global warming is occurring?
Beware of global warming skeptics trumpeting record snowfalls this winter as an excuse to doubt that global warming is occurring. One should primarily look at global temperatures on a scale of decades to judge the validity of global warming. Dr. Ricky Rood, who writes our Climate Change blog, put it this way in his current blog, Creeping Onset of Spring and in an earlier blog, Water, water, water:

This year has been very snowy in the northern hemisphere. That it is snowy does not suggest that it is colder. If it gets warmer, it does not mean that we no longer see freezing temperatures in places like Michigan. If it gets warmer there is more water in the atmosphere, and when there is precipitation there will be more precipitation, and if it is below freezing, then that precipitation will be ice and snow. The high mountains near the coast, like the Cascades and the Sierra Nevada would expect more snow. This is also true for the high altitudes parts of Greenland and Antarctica. From a climate point of view it is more important to look at snow cover in the late winter and early spring. Is the snow melting earlier?

Figure 2. Average February arctic sea ice coverage as observed by satellites between 1979 and 2008. Image credit: National Snow and Ice Data Center

Arctic sea ice recovers a bit
It will be interesting to see if this year's heavy Northern Hemisphere snow cover melts earlier than usual, as this will have a big impact on the annual Arctic sea ice melt. We're starting off with more ice surface area in the Arctic than in the past four years--February 2008 Northern Hemisphere sea ice extent was greater than each of the previous four years, thanks to cooler than usual temperatures over much of the Canadian Arctic. However, this was still the fifth lowest ice extent on record for the month of February, and 8% below its extent in 1979 when satellite measurements began, according to the National Snow and Ice Data Center. February was the third straight month that a new monthly minimum Arctic sea ice record was not set, following a string of five months in a row where monthly records were set. The extra sea ice extent will help to reduce the amount of melting this summer, but this effect will probably be overshadowed by the fact that natural wind patterns have forced a large amount of thick, multi-year ice out of the Arctic this winter. This has left much of the sea ice very thin, making it very vulnerable to melting. For the first time on record, the edge of thin first-year ice has pushed beyond the North Pole. IF we get another relatively warm and sunny summer in the Arctic in 2008, we will likely see Arctic sea ice loss surpassing last year's astounding collapse.

Annual WeatherDance contest ready for registration!
Armchair forecasters, now's your chance to shine! WeatherDance, based on teams in the men's and women's NCAA basketball tournaments, allows players to predict which team's city will be hotter or colder on game day in each round of the Big Dance. Beginning March 17, players can make their forecasts at the Weather Dance Web site at: www.weatherdance.org. The site will be updated with cities promptly after NCAA seeding announcements. Team selection occurs March 16 for men and March 17 for women. First round Weather Dance selections must be entered by 11:59 p.m. EST March 19. Players can register now and receive periodic reminders as the game progresses.

"Officially, Weather Dance began as a class project to get students involved in weather forecasting, but we kept it around because it got popular. People think they can do better forecasting than the meteorologists. Well, here's their shot!" said Perry Samson, WeatherDance creator, co-founder of the The Weather Underground, Inc., and Professor in the Department of Atmospheric, Oceanic and Space Sciences at the University of Michigan.

This is the third year for the game. Last year more than 2,000 people played. Most play merely for the thrill, but many science teachers involve their classes as part of meteorology units. The winning teacher will receive an invitation and $500 to join the Texas Tech/University of Michigan Storm Chasing team this spring for a day of tornado chasing. Other winners will receive a Weather Underground umbrella or a copy of the book "Extreme Weather," by Christopher C. Burt.

Jeff Masters

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

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274. cchsweatherman
3:54 PM EDT on March 14, 2008
Good afternoon all! Starting to feel better now, but still will not post my report supporting my hurricane season predictions posted on my site.

Based upon radar and satellite analysis, it looks like there may be a rapid change in the forecast for Central and Southern Florida tonight as a strong convective complex has developed throughout the day in the Eastern GOM. It continues moving towards the SE at a rather quick clip. I have begun to notice a strong bow-echo forming about 100 miles west of Tampa. This will have to be watched during the next few hours to see if it maintains itself while approaching the coast. What appears to be a weak trough has developed across South Florida in a near horizontal line with the southern tip of Lake Okeechobee as some heavy showers and isolated storms have started to build. Things look much more conducive for showers and storms in South Florida than earlier. Notice that instability has increased over the entire area, but we all know that a good gust front can immediately stabilize the atmosphere. All in all, looks like Central Florida including the Lake (which currently stands at 10.16 feet) should get some nice soaking rains into the night, but I do not anticipate much heavy rain for South Florida as the complex should lose steam by then.
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271. surfmom
7:55 PM GMT on March 14, 2008
Love looking at those wave maps! Gets the blood moving. Also good to check is Magicseaweed.com
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269. AWeatherLover
7:54 PM GMT on March 14, 2008
I didn't surf in Wilma... I think I got scared after Frances. Frances was super fun, but hell to paddle out in with 8 ft waves crashing on top of you and no channel. I prefer to stick with 4 ft. Can't wait for the Ron Jon Surf Pool to open up. Hopefully this summer. Link Perfect waves every time. And warm water all year round.
Anyone have any idea when/if the storms of the coast will reach us?
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268. Patrap
2:50 PM CDT on March 14, 2008
GOM 60 Hour Wave Forecast Model Link
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267. surfmom
7:48 PM GMT on March 14, 2008
Plus, to be honest, I learned to surf late in life (my youngest son taught me for a Mother's Day present) I've had my nose broken (Hurricane Francis) and my head split open - fin slice (Ernesto) so at this stage of the game I don't need or want anything over chest/shoulder high, I hate rip currents - so if it waves for the groms, I am a happy camper. the kids call me the Nanny, cuase I laugh out loud and I am 50 --it's a hoot to surf w/young kids....I forget I am old. When my son is with me I venture further (hurricane Wilma - I thought I was going to DIE! - like a roller coaster with no buckle in the seat.) Hurricane Wilma did produce the most incredible, heavy, beautifully formed waves the west coast of fl had seen in decades...it was Epic!
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266. AWeatherLover
7:49 PM GMT on March 14, 2008
I hate surfing in the cold... Can't wait for summer. Thanks Storm! How have you been?
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263. surfmom
7:46 PM GMT on March 14, 2008
YUP, figure I got to be out by sunrise - have a nice sandbar that faces perfect - usually puts out swell till there's none.
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262. surfmom
7:45 PM GMT on March 14, 2008
The low moving through the Gulf should set up some nice waist high waves - Gulf is 66, last front caused some upwelling so the water cooled some. Still wet suit water...grrrr
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261. AWeatherLover
7:44 PM GMT on March 14, 2008
surfmom- swell supposed to rapidly die out Sunday. That's what I heard. Better get out there early, that's what I'm doing.
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260. surfmom
7:42 PM GMT on March 14, 2008
Spits of rain in SRQ. Looking for some surf from this weather. Saturday & Sunday --Work Sturday, so it looks like Sunday if it stays up
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259. AWeatherLover
7:41 PM GMT on March 14, 2008
Hey Adrian, how is that research on La Nina going? Also, any idea about west central FL? I nosted someone already posted this, but it seems that the storms die off as soon as they get to the coast. Are we gonna get some actual rain?
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257. AWeatherLover
7:27 PM GMT on March 14, 2008
I know what I posted was just a web page, that's why I'm interestd in the data that disputes it. Actual data, not web pages or opinions. Apologies, if that's not what my post sounded like. Someone showed me that web page and I was't sure how to dispute the information on it with actual data and reports.
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255. hurricane23
3:28 PM EDT on March 14, 2008
Good afternoon!

I can now confirm the changes going on at the NHC.

The TWO will be issued at the synoptic times of 00Z, 06Z, 12Z and 18Z. It is effective May 15 with the issuance of the Eastern Pacific TWO and June 1 with the Atlantic TWO.A PNS will be issued during the next few days.

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254. Patrap
2:22 PM CDT on March 14, 2008
Gore addresses MPs on warming today
Kay Benedict
Friday, March 14, 2008 08:42 IST

NEW DELHI: Will Al Gores first-ever lecture on global warming and climate change to Indian parliamentarians on Friday help prime minister Manmohan Singh sell the contentious India-US civilian nuclear deal to MPs opposed to it?

Even as Delhi pushes for the deal and clean energy, former US vice-president Al Gore, who won the 2007 peace Nobel and shared it with the UN inter-governmental panel on climate change, will make a strong pitch for clean environment as he addresses Indian lawmakers on Friday.

Al Gore, who holds the view that global warming is the greatest challenge mankind ever faced, is slated to talk on his pet topic at Parliament Complex Library. Indian climatologist Rajendra Pachauri, who chairs the UN panel on global warming, will also address the MPs.

With India taking a keen interest in climate change and global warming, the prime minister has appointed his special envoy on the nuclear issue Shyam Saran as his special representative on climate change as well.

Underscoring the importance of the subject, Lok Sabha speaker Somnath Chatterjee has also decided to constitute a 21-member parliamentary forum on global warming and climate change and has written to major political parties to nominate MPs to the panel.
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251. Patrap
2:12 PM CDT on March 14, 2008
No Mesoscale Discussions are currently in effect.
Most recently issued Mesoscale Discussion #0399.Link

SPC Page NWS Link
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248. surfmom
7:05 PM GMT on March 14, 2008
HouseofGryffin - I remember my husband saying the very same thing.....now two boys later LOL --turned out real cool for him, one is a commercial diver (welding & emt) the other is 14 years old playing 4-goal polo (horses)

Also thanks for the radar guys, Patrap and JFlorida - wonder what SRQ will get. Hopefully RAIN! -
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247. Patrap
2:08 PM CDT on March 14, 2008
Thru next Weds never goes below 50F here,Hard to get any significant freezes to the far South now.The Sun angle iz getting higher every day.

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246. Michfan
7:02 PM GMT on March 14, 2008
Cloud tops starting to go over 20,000 ft.
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243. Patrap
1:59 PM CDT on March 14, 2008
Reds are a Poking and a growing in Texas on the US Temp Map. Link
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241. Patrap
1:55 PM CDT on March 14, 2008
It's humor Gryff.If ya not able to catch some.
Dont throw.
We who have families are mostly proud of them,kinda folks.
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240. Michfan
6:55 PM GMT on March 14, 2008
Damn look at those temps in Texas. 90's!
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238. Patrap
1:51 PM CDT on March 14, 2008
227. That's why I will never have a family.

Phew, thanks ..I was worried fer a spell.

The avatar scares the dogs,LOL
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237. latitude25
6:48 PM GMT on March 14, 2008
15 mins to reflect on hoping i get more time the next day.

Mich are you an inspiration to us all.

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236. lindenii
6:50 PM GMT on March 14, 2008

Hows about we step away from global warming for a bit and take a look at data gathering and interpretation for a moment or two.

Lets talk resolution and data gathering.

Lets say I have been anaylzing a 9 sq kilometer area with equipment that just happens to have the identical resolution of 9 sq km. I've been using the system for the last thrity years with good results. Recently I was approached about getting hooked up with a system that has a resolution of 1 sq km.

Now, my problem is that I am wondering what that all really means. Does that mean that I will be geting nine times more data to analyze or will I be getting something else instead.

If I were to want to be able to compare the 9 sq km resolution with the 1 sq km data, what would I do to make sure that the data was equal in weight. After all, I would really like to be able to see what the differences would be if I ran both sets of equipment side by side for a period of time.

How would the data collected at the 1 sq km resolution be manipulated in order to 'dumb it down' to the data collected by the 9 sq km resolution equipment.

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232. Patrap
1:44 PM CDT on March 14, 2008

No Mesoscale Discussions are currently in effect.
Most recently issued Mesoscale Discussion #0399.Link

SPC Page NWS Link
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231. Michfan
6:43 PM GMT on March 14, 2008
Just saw that Pap. I foresee some watches going up sometime soon.
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230. Michfan
6:42 PM GMT on March 14, 2008
Typical day:

12 hours: Work
6 hours: Sleep
5:45 : Food, kids, etc...
15 mins to reflect on hoping i get more time the next day.
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229. Patrap
1:43 PM CDT on March 14, 2008
Speaking of Radar..

TVS signature offa Tampa..
Tampa Base Reflectivity 0.50 Degree Elevation Range 124 NMI Link
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227. latitude25
6:39 PM GMT on March 14, 2008
We all get 24 hours each day.
That will change when you get older and a family.
You only get 30 seconds then.
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226. roberie
6:39 PM GMT on March 14, 2008
GW - Saw this the other day and got a good laugh. Sad thing is there are probably people that believe it.

Don't you think that extra hour of sunlight every evening from daylight savings time is what is causing the global warming?

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225. Patrap
1:36 PM CDT on March 14, 2008

The day has several definitions.

[edit] International System of Units (SI)

A day contains 86,400 SI seconds.[1] Each second is currently defined as

… the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom.

In the 19th century it had also been suggested to make a decimal fraction (1⁄10,000 or 1⁄100,000) of an astronomic day the base unit of time. This was an afterglow of the decimal time used with the French Republican Calendar, which had already been given up.

[edit] Astronomy

A day of exactly 86,400 SI seconds is the fundamental unit of time in astronomy.

For a given planet, there are two types of day defined in astronomy:

1 apparent sidereal day
= a single rotation of a planet with respect to the distant stars
(for Earth it is 23.934 solar hours)
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224. Michfan
6:35 PM GMT on March 14, 2008

Got some boomers on the way it looks like. Whats the level of Lake O at the moment?
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