Forecaster: Two phenomena responsible for world's bizarre weather
A graphic outlining sea temperature anomalies the first week in January shows drops in the Pacific as air temperatures rise between the U.S. and Europe (continents in gray). La Niña and the North Atlantic Oscillation are to blame, an expert says.
January 13th, 2011
03:35 PM ET

Forecaster: Two phenomena responsible for world's bizarre weather

The catastrophic weather events taking place across the globe – from Brazil’s and Australia’s flooding to the Eastern United States’ heavy snowfall – have two likely explanations.

Tony Barnston, lead forecaster at Columbia University’s International Research Institute for Climate and Society, said two phenomena – La Niña and the North Atlantic Oscillation – are likely responsible for the patterns we’re seeing.

Though La Niña is different every time, it can be simply defined as a drop in water temperature in the eastern and central tropical Pacific Ocean. This particular La Niña appeared in July, Barnston said, and will last through spring.

During La Niña, there is less rainfall in the tropical Pacific and a horseshoe pattern of warm water typically forms in the North Pacific, the coast of Southeast Asia and the seas around Indonesia and Australia (check out the graphic above).

In this case, though, “the whole globe looks to be compensating,” Barnston said, noting that it’s difficult to determine if  La Niña spawns individual weather events.

While Southeast Asia and Australia can typically expect warmer oceans and more rainfall during La Niña, the affected area stretches farther west this year and includes Sri Lanka and the southern tip of India, Barnston said.

There is presently a massive rescue operation under way in Sri Lanka to save victims of flooding that has already killed at least 13 people. Floods have killed another 40 people in the Philippines, and Australia has been inundated with deadly flooding reportedly estimated to cover an area the size of France and Germany combined. To the east of La Niña, South America's north coast has been slammed with rain, and hundreds have been killed in Brazil's flooding and mudslides.

La Niña usually means warmer temperatures in the United States, particularly the Southeast, but this year the North Atlantic Oscillation is trumping La Niña.

Since November, we have been in the negative phase of the North Atlantic Oscillation, Barnston said, meaning that air temperatures between the eastern U.S. and Europe will drop. This causes temperatures to rise in places like northeast Canada, Greenland and Iceland, as the mercury drops on thermometers in the eastern U.S.

Weather experts call it a see-saw pattern, and it will eventually affect water temperatures, though that’s a secondary effect, Barnston said.

So while La Niña would normally mean dryer, warmer weather for folks in the southern United States, “the North Atlantic Oscillation has superseded the La Niña” this year, bringing El Niño-like winter temperatures and snow to the Southeast, he said.

CNN meteorologists reported earlier this week that snow was present in every U.S. state but Florida.

Though La Nina typically lasts until April or May, the North Atlantic Oscillation can move from a negative to positive phase mid-winter. Barnston said the Southeast “could be warmer and dryer than normal later this year if the North Atlantic Oscillation ceases and desists.”

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Filed under: Australia • Brazil • India • Indonesia • Philippines • Sri Lanka • Tropical weather • U.S. • Weather • Winter weather
soundoff (963 Responses)
  1. lefty avenger

    Could it be Global Warming? There's too many climate change denialists living in denial here in america.

    January 14, 2011 at 9:23 am | Report abuse |
    • Matt

      There is global climate change if humans are not on the earth, remember this planet was extremely hot when the dinosaurs rules the earth. The dinosaurs became extinct because of the ice age, I will agree if you say we are partially responsible to accelerating the climate change but to think we can stop it is insanity.

      January 14, 2011 at 9:41 am | Report abuse |
    • Cedar Rapids

      'There is global climate change if humans are not on the earth, remember this planet was extremely hot when the dinosaurs rules the earth.' – the earth was also way different climatically and geologically then.

      'The dinosaurs became extinct because of the ice age' – erm, no, no they didnt, the ice age happened waaaaaaaay after the dinosaurs became extinct.

      January 14, 2011 at 9:54 am | Report abuse |
  2. David

    Get over the weather already. It is not "bizarre" weather. Weather changes every year, decade by decade, 50 years at a time, etc... There are patterns.

    It seems every single year lately we have some state or city somewhere breaking records with heat and snowfall and cold temps. You know why? The devices we use to measure this stuff are more accruate than ever before.

    Global warming is BS. Get over it.

    January 14, 2011 at 9:25 am | Report abuse |
    • KNKLHEAD

      Hey, David. Global Warming is very easy to prove. Want to do a little lab 101 homework? Since you're on the internet do a search for some scientific material that shows the average temperature of the earth.

      Now, Global Warming would mean that you might find that the average temperature of the earth is getting warmer and warmer. Can you report back to us and let us know what you find out?

      January 14, 2011 at 9:46 am | Report abuse |
    • mostlyyoung

      I believe the ice age was caused by all the large dinos passing gas. They cause global freezing. Everyone load up on gas-ex or another ice age is coming....ppl keep drinking the cool-aid Al Gore is selling...hes getting rich!

      January 14, 2011 at 10:01 am | Report abuse |
  3. Bemused

    First off, climate change is a real problem and it IS happening. The only true debate I can see is over whether humans are causing it directly or whether the earth is simply reverting to its "normal" temperature and weather patterns (don't forget, we are still emerging from an ice age). Either way, we've got serious problems ahead.

    @trav202: Do Ric Flair next!

    January 14, 2011 at 9:27 am | Report abuse |
    • Volatar

      Then comes the next Ice Age.....What fun.

      January 14, 2011 at 9:35 am | Report abuse |
  4. steve

    This guy is the lead forecaster and he says that the Southeast "COULD BE WARMER AND DRYER THAN NORMAL LATER THIS YEAR IF THE NAO CEASES AND DESISTS?" Yo, Tony...if you are the lead forecaster, how about FORECASTING whether or not the blocking pattern will break down?

    January 14, 2011 at 9:28 am | Report abuse |
  5. clg

    Orrrr... Its because the Earths N and S poles have shifted more than 45 feet in fifteen days.

    January 14, 2011 at 9:28 am | Report abuse |
  6. jamesbrummel

    To all you experts on weather and climate: heavy snow, heavy rain, high surface temps, low surface temps, here and there, last year, this year, that's called WEATHER. The temps, particle counts, pressure, humidty over long long periods of time is CLIMATE. So no, this weirdness, the last very hot summer and the this very cold winter are not symtoms of CLIMATE CHANGE. The overwhelming evidence of climate change is in lengthy, detailed statistics over centuries, chemical analysis of fossils, etc. So go back to the lab, Einsteins, you know nothing.

    January 14, 2011 at 9:29 am | Report abuse |
    • Matt

      And how accurate were the measuring devices centuries ago? We know there was a time when the entire planet was tropical and a time when the entire planet was arctic, wouldn't you think the natural progression of the earths temperature would be to change?

      January 14, 2011 at 9:45 am | Report abuse |
  7. Observation

    Predict global weather – hell – they can't even get the local weather from day-to-day right! We are meaning making machines when real – un-tainted – data is distorted to make a preconceived and desired outcome appear real. The real Universe seems to step in and expose human being's master plans as fantasy for those of us who are awake to comprehend reality.

    January 14, 2011 at 9:30 am | Report abuse |
  8. Russ

    It's all caused by global warming. That's why it's fourteen degrees right now in upstate NY. Was five degrees the other morning. Forcast is nine tommorow morning. Has to be global warming. What else could it be?

    January 14, 2011 at 9:30 am | Report abuse |
  9. Kris

    Wait a second..... It is suppoed to be warmer in the South? I live in Texas and I am freezing my a** off.

    January 14, 2011 at 9:30 am | Report abuse |
    • sparky

      head over to Crawford and slap the murdermonkey around for me

      January 14, 2011 at 9:32 am | Report abuse |
  10. Al Gore

    Call me.......I'll sell you a solution. Just dont ask me why Temps are also rising on Mars and Venus.

    January 14, 2011 at 9:30 am | Report abuse |
  11. Bron

    It's because you touch yourself at night.

    January 14, 2011 at 9:32 am | Report abuse |
  12. stonedwhitetrash

    The apocalypse and armageddon are upon us. the horror! The horror!

    January 14, 2011 at 9:32 am | Report abuse |
  13. me

    DECEMBER 21, 2012- IT'S STARTING– RUN FOR YOUR LIVESSSSSSSSSSSS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!– hehe

    January 14, 2011 at 9:33 am | Report abuse |
  14. Gimble

    All the heated talk. so what..... It's still damn cold here in Texas

    January 14, 2011 at 9:36 am | Report abuse |
  15. canuck

    send some snow to Canada.. we miss it.

    January 14, 2011 at 9:38 am | Report abuse |
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