Accuweather US winter forecast

[PalmatierMeg]

Today I found these forecast maps and article in the Washington Post

AccuWeather released its winter forecast this morning and is calling for a repeat performance of last winters harsh conditions, especially across the northern tier of the U.S. Like the winter of 2010-2011, La Nina, an episodic cooling of the tropical Pacific ocean, is the dominant player influencing its predictions.

La Nina events tend to favor a strong polar branch of the jet stream, which activates big cold air outbreaks. And when the cold air interacts with warm air coming up from the south, big storms often develop in the transition zone.

The State College-based forecast company anticipates the transition zone will set up slightly west of where it did last year, dealing winters most severe blow from the Ohio Valley to the Great Lakes and Northern Plains.

The way the jet stream is expected to be positioned during this winters La Niña will tend to drive storms through the Midwest and Great Lakes, AccuWeather said. Last year, the jet stream steered storms farther east along the Northeast coast, hammering the Interstate 95 corridor.

This year, cities like Detroit, Cleveland, Chicago and Minneapolis may be hardest hit.

In the mid-Atlantic (including Washington, D.C.), AccuWeather senior meteorologist Paul Pastelok predicts winter will start off with a bang, but then gradually moderate. He examined analogs, past years with weather patterns similar to the present, and found the winter 2008-2009 closely mirrors what this region might expect.

We saw most of our winter in the first half, Pastelok said. January then flipped, it became mild and we saw quite a bit of rainfall.

During the second half of the winter, Pastelok believes the jet stream will migrate west, allowing the cold air to erode in the mid-Atlantic and Northeast. Such a shift would favor Appalachian cutters, storms tracking well to the west of the I-95 corridor. These storms usually bring rain and/or mixed precipitation along the Eastern seaboard rather than wsnow.

The second half of winter may also feature high pressure building over the Southeast as the jet stream shifts west, favoring occasional mild stretches Pastelok said.

Overall, heres how Pastelok described the evolution of winter temperatures in the Washington, D.C. metro region:

December is probably going to be the coldest month - November back and forth a little bit. In January, Im leaning a little bit cold, but February turns it around. Were aiming at near normal temperatures. There will be ups and down, mostly downs the first part [of winter], mostly ups second half.

As for snowfall, using a combination of past analogs and computer model guidance, Pastelok is predicting slightly above average snow in the Washington, D.C. metro region.

I could see snowfall this year reaching close to 20 but it would have to come earlier on, Pastelok said.

While only 7.5 of snow fell during the 2008-2009 analog year in D.C., Pastelok sees signals in the Arctic sea ice evolution which may favor a negative phase of the North Atlantic Oscillation (NAO) pattern , conducive to cold, snowy weather during the first part of winter.

AccuWeather meteorologist Henry Margusity shared ideas similar to Pastelok on his Facebook page:

Overall, I like the forecast, just think the bulk of snow will be in the Appalachians and Northeast this year. Above normal snows for DC to NYC I believe. Also, St Louis, Chicago, Detroit, Cleveland also above normal.

Matt Ross, lead author for Capital Weather Gangs winter outlook to be released around November 1, had this take on AccuWeathers outlook

Although Accuweathers outlook is a pretty cold and snowy one for the Midwest and west of the mountains, the key takeaway for our region is to expect a fairly typical La Nina pattern. Quite cold at times, but with a prevalent storm track to our west, often dry when it does get cold

CWGs winter weather expert Wes Junker sent along the following reaction:

I agree with Matt. The forecast is pretty much in line with a typical La Nina-like storm track to our west. La Ninas tend to have big swings in temperatures.... This year the complication is what the NAO will do as its been running negative for decent chunks during the last several winters. The same will probably hold this winter as we seem to have cycled into a period with more blocking in the North Atlantic than we had in the 1990s and early part of the decade. That blocking [negative NAO] probably will give us some chances for snow even with a La Nina. But with such a strong northern stream, we still may only get fringed with storms sort of like last year. Except for the Northern Plains, I dont think this will be an easy year for seasonal forecasters.

Here are some additional summary points from the AccuWeather outlook:

Northeast U.S.: Not as extreme as 2010-2011; a few significant impact winter storms; much above normal snow north and west of the Appalachians.

Southern States: More ice than snow for northeastern Texas and Oklahoma into Kentucky and Tennessee; significant severe weather and flood events in lower Mississippi Valley in February.

Southwest and Texas: Mild and dry, more drought in Texas - with below average precipitation in entire region.

West coast: Big temperature swings, starting warm in December, then cooling. Potentially a period active storminess with excessive rain and snow.

It looks like the coming winter in much of FL will be milder, which after the past 2 winters is a true blessing. Of course, that's assuming Accuweather is spot on. Has anyone else heard other winter forecasts?

[happ]

Thanks Meg, for the interesting info. It appears consistent with other weather service forecasts for winter in north America. I hate to put full confidence in long-range predictions, but the atmospheric signals are favorable for a much milder winter in the southern U.S. It may be California's turn for a cold winter

[nachocarl]

Thanks Meg, for the interesting info. It appears consistent with other weather service forecasts for winter in north America. I hate to put full confidence in long-range predictions, but the atmospheric signals are favorable for a much milder winter in the southern U.S. It may be California's turn for a cold winter

I thought last year was cold...near record low (here in Vista) all winter long. Today didn't boad well, already winter type weather in early Oct. Can't fight mother nature though. Bring it on!

[happ]

Thanks Meg, for the interesting info. It appears consistent with other weather service forecasts for winter in north America. I hate to put full confidence in long-range predictions, but the atmospheric signals are favorable for a much milder winter in the southern U.S. It may be California's turn for a cold winter

I thought last year was cold...near record low (here in Vista) all winter long. Today didn't boad well, already winter type weather in early Oct. Can't fight mother nature though. Bring it on!

Hi Carl,

My comments were essentially about frost\ freezing temps and the loss of palm trees as a result. Last winter in California, was, in-fact a bit cool per the norm, as you point out but there were no widespread outbreaks of frost or extended periods of very cold temps. The coolness last winter was reflected in day temps due to much more rain than normal; Dec & Feb experienced cooler than normal maximum temps & minimums were below normal during Feb but the coldest night temps were near 40F\ 4.4C for most areas west of the mountains & very few areas observed frost. Vista, like Oceanside, Temecula & Corona, is located in a region prone to windless clear nights so minimums are generally colder than the surrounding area. Vista is also some distance from the ocean so it doesn't benefit from the relatively warm Pacific waters during winter.

For example, here is the data from last winter [1st # is monthly minimums F\ second # coldest minimums F for Dec\ Jan\ Feb:

San Diego: 52\ 51\ 50 -- 44\ 45\ 44

Carlsbad: 50\ 50\ 47 -- 40\ 40\ 39

Oceanside: 43\ 40\ 39 -- 31\ 34\ 28 [cold pocket]

Los Angeles: 50\ 48\ 46 -- 37\ 43\ 39

LAX: 51\ 50\ 47 -- 39\ 44\ 41

Burbank: 47\ 45\ 42 -- 34\ 36\ 34 [cold pocket]

Average minimums were generally 2F or more below normal [especially in Feb].

http://www.nws.noaa.gov/climate/index.php?wfo=sgx

[gsytch]

The general agreement for Tampa Bay forecasters has been "watch the AO" as they are unsure of its influence. Last year saw record cold in Dec into the first half of Jan, but it moderated quickly and that is what the forecast above looks like. Feb and Mar were beautiful and warm. After two horrible winters of cold front after cold front, and break sure would be nice!

[MattyB]

That map is hilarious! Seriously, that's supposed to be something? Brrrr cold, some rain, mild. Sound official.

[nachocarl]

That map is hilarious! Seriously, that's supposed to be something? Brrrr cold, some rain, mild. Sound official.

Yes, please express "Brutal" in terms of Fahrenheit or Celsius. And,where is the cut off from Brutal to say, ruthless or coldhearted? Or the most dreaded of them all, backbitingly coldblooded!

[happ]

That map is hilarious! Seriously, that's supposed to be something? Brrrr cold, some rain, mild. Sound official.

Yes, please express "Brutal" in terms of Fahrenheit or Celsius. And,where is the cut off from Brutal to say, ruthless or coldhearted? Or the most dreaded of them all, backbitingly coldblooded!

Your welcome!

[nachocarl]

Thanks Meg, for the interesting info. It appears consistent with other weather service forecasts for winter in north America. I hate to put full confidence in long-range predictions, but the atmospheric signals are favorable for a much milder winter in the southern U.S. It may be California's turn for a cold winter

I thought last year was cold...near record low (here in Vista) all winter long. Today didn't boad well, already winter type weather in early Oct. Can't fight mother nature though. Bring it on!

Hi Carl,

My comments were essentially about frost\ freezing temps and the loss of palm trees as a result. Last winter in California, was, in-fact a bit cool per the norm, as you point out but there were no widespread outbreaks of frost or extended periods of very cold temps. The coolness last winter was reflected in day temps due to much more rain than normal; Dec & Feb experienced cooler than normal maximum temps & minimums were below normal during Feb but the coldest night temps were near 40F\ 4.4C for most areas west of the mountains & very few areas observed frost. Vista, like Oceanside, Temecula & Corona, is located in a region prone to windless clear nights so minimums are generally colder than the surrounding area. Vista is also some distance from the ocean so it doesn't benefit from the relatively warm Pacific waters during winter.

For example, here is the data from last winter [1st # is monthly minimums F\ second # coldest minimums F for Dec\ Jan\ Feb:

San Diego: 52\ 51\ 50 -- 44\ 45\ 44

Carlsbad: 50\ 50\ 47 -- 40\ 40\ 39

Oceanside: 43\ 40\ 39 -- 31\ 34\ 28 [cold pocket]

Los Angeles: 50\ 48\ 46 -- 37\ 43\ 39

LAX: 51\ 50\ 47 -- 39\ 44\ 41

Burbank: 47\ 45\ 42 -- 34\ 36\ 34 [cold pocket]

Average minimums were generally 2F or more below normal [especially in Feb].

http://www.nws.noaa.gov/climate/index.php?wfo=sgx

Definitely appreciated, and I always read your posts to get an idea of what is coming! I know my front yard is always towards the cold pocket side as I have two downhill streets converging there pushing the cold air in. The back yard has more canopy and is protected so it tracks with Vista temps, the difference can be almost 5 degrees in a 30 ft diameter! I am putting more A. cunn in the front to establish canopy and most stuff that I have planted this year out there should be good to 25F, so hopefully I can keep everything alive.

Here is to hoping for a warm wet winter.

[SubTropicRay]

The Arctic Oscillation can wreak havoc on any forecast and that can only be predicted 2 weeks or less in advance.

[Palm crazy]

That map looks like a normal winter for everyone, cold in the north, mild in the south. Windy, Rainy, Cold, Foggy in the PNW, yep looks normal to me.

Last winter we had cooler than normal highs. You never know how cold or warm its going to be here in winter.

My coldest/ warmest lows last winter....November 15F/ January 30F. Had one big snow storm in February, Low 20, coldest in March 28F.

I guess this winter will be no different, hopefully nothing lower than 18F and no big wet snow events. This winter is starting off with an early rainy season.

The word is the west coast is 'suppose' to have an early spring next year. I'm sure mother nature has a few curveballs ahead.

[displaced_floridian]

With a negative NAO likely to set up in Dec. I think the dreaded "Greenland Block" will again be an influence on the EAstern US. The type of hurricane season we've had, with troughs digging to the SE US, and even across the tropical Atlantic, (which is why no storms have made it across without recurving to the NE) I believe means another Dec. Like the last, with "one cold front after another" in Florida and the SE US. I hope I'm wrong.

Edited October 10, 2011 by displaced_floridian

[happ]

The Arctic Oscillation can wreak havoc on any forecast and that can only be predicted 2 weeks or less in advance.

Yeah, and you know, Ray, a mild winter can still have a short outbreak of sub-freezing temps. It really is a toss-up of many factors. La Nina seemed to act differently last winter than historic episodes; rain amounts in California that were higher than most El Nino years!