La Niñas, Arctic Oscillations, and Blizzards, Oh My!

February 2, 2011

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Welcome to Weather Math 101.

Today’s equation:
1 Strong La Niña + 1 Insane Arctic Oscillation
= 1 giant blizzard for 100 million people

Groundhog Day arrived and instead of a photogenic rodent, we got a 2,100-mile-long blizzard. One third of the nation is being slammed by a huge storm that stretches from New Mexico to Maine.

Click to enlarge photo and find the hidden nation!

The Groundhog Day Blizzard buries the USA
Source: NOAA

If you live in a city, you are being buried in snow and traffic is paralyzed. If you are in the country, you are desperately trying to protect your livestock and worrying about your winter wheat crop. You probably don’t care if a dozen groundhogs saw their shadow.

Eastern groundhogs tend to be more likely to see their shadows during an El Niño and as several readers of the last blog noted, this is a La Niña year. Poor Punxsutawney Phil probably needed a snow shovel to get out of his burrow. When he did, there was no shadow.

So what do La Niñas do – besides creating wretched woodchucks? Typically La Niñas are cold weather events. Over a million square miles of abnormally cool water develops in the Tropical Pacific. This cools the tropical air mass overhead which in turn changes air pressure patterns and winds. With that much cooler air, wind and weather patterns are changed all over the globe.

Here in North America, cold weather builds up over the Northwest. As winter progresses, the cold expands eastward. In a strong La Niña, like the one we have this winter, the cold reaches the Northeast by mid-winter AKA February 2.

Click to expand below.

Typical January–March Weather Anomalies and Atmospheric Circulation During Moderate-to-Strong La Niña.
Credit: CPC/NCEP/NWS

Unfortunately, we are not just dealing with La Niña; we also have a wildly fluctuating Arctic Oscillation. In December, it was dramatically negative, allowing cold polar air to plunge to Florida. Now it is sharply positive (over +2.0), allowing warm air from the Gulf of Mexico to waft north. The cold air in the north, with wind chill, may be below zero, but parts of the Gulf are in the 70°s.

The La Niña weather pattern is allowing the cold air to smash into the warm, wet air. Think of a car crash – it’s not pretty. Two giant air masses crashed and we are in the middle. Ugh!

And the groundhogs don’t like it either.

Tell us about what the storm is doing in your area. I have 18 inches of snow and I live 300 miles from the Mexican border!

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Evelyn Browning Garriss, historical climatologist, blogger, writer for The Old Farmer's Almanac, and editor of The Browning Newsletter, has advised farmers, businesses, and investors worldwide on upcoming climate events and their economic and social impact for the past 21 years.

Comments

The pictures of this storm

By MeganR

The pictures of this storm are so incredible.

I think everyone is in a bit of disbelief over what the storm actually did. There are miracle stories everywhere as well.

Thank you for this article.

South Central PA

By Frogii

Had very little snow, but freezing rain and about 1/2" of ice coating everything overnight on Tuesday night. Then temps went up above freezing on Wednesday, in the mid-30s and high winds came and cleaned the ice off the trees. It's been very strange weather here this winter! It's supposed to be up in the high 30's tomorrow then temps fall back down and sleet and freezing rain come again on Friday night and Saturday.

Southern Winter

By Janelle Lear

Usually this time of year in the Houston area we are cleaning up fallen leaves and preparing for spring planting. Not this year - we have had two one-week spells of sub-freezing temps and no one wants to be outside longer than absolutely necessary. Water in animal troughs is frozen, even inside their barns/shelters. We're digging out clothing not worn in probably several years! I live 40 miles NW of Houston and we are expecting a couple inches of snow (winter precipitation per the weather channel). No accumulation but don't talk to be about global 'warming.' Actually the change is refreshing. :-)

The Big Blizzard

By jjstewart

I live in Southern Wisconsin. We have 10.8" on top of what we had however just south across the stateline into Illinois there is 24" on the ground. They put snowplows on the front of garbage trucks and called in extra plows. We have a four ft. drift on our patio with some cars still buried. A civil emergency was called as so many people continued to drive in spite of the 10-15 ft. drifts building up across the roads. All major roads were closed from Milwukee, WI south. Today - Thurs. - schools are still closed and many businesses are slow to open. It's been a mess but we're slowly digging out.

blizzard of 2011

By carlw1942

I live in Dundee, Mi.; (25) mi. south of the University of Mich.
3:30 a.m. It rook my son (1.5) hrs. to dig out to go to work.
5:00 a.m. It took him (1.5) hrs. to drive (45) mi. to work.
Worked (8) hrs., drove home, to rest & repeat work routine tomorrow. That's what they call "Making a Living" here in Mi.
Thank God he has a job, esp., here in Mich.
Carl Wadsworth

Raining Snow!

By Catherine Boeckmann

It was raining snow in NH--very light, very fast--but we're used to snow versus your 18 inches near Mexican border! Looking forward to awesome skiing this weekend.

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