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. lysander

    Well, thankfully it can't be Global Warming since no one can prove it exists. It must instead be proven science such as God Dust accidentally going bad and causing the Angel Castles made of cotton above us to act in aggression until we all clap in unison and sing hymns to reverse the bad juju happening.

    January 13, 2011 at 7:01 pm | Report abuse |
  2. your friend

    can we all just agree that the world is ending? oh sweet release....

    January 13, 2011 at 7:03 pm | Report abuse |
    • BuzzMann

      It is about dang time,I been waiting since 2000.

      January 13, 2011 at 9:16 pm | Report abuse |
  3. jimvsmij

    It's the beginning of the end.
    The Increased CO2 in the air will allow more solar energy to warm the oceans and air, which will cause more circulation and precipitation making the planet a lot wetter and warmer. This along with the CO2, which plants love, will cause a greening of the earth as rain forests spread from pole to pole not seen since the Dinosaur age when CO2 levels were much higher than now. With all the abundance of plant matter herbivores will grow in physical size to gigantic proportions, followed closely by the predators that will feed on them. That, I'm sorry to say, will be the final nail in the coffin for mankind as we become prey to Giant Bears, Wolves, Lions, Ferrets, etc....
    Stock up on ammunition now because you will need it in the coming years......

    January 13, 2011 at 7:04 pm | Report abuse |
    • Rambo

      Well, given the time it takes to a species to grow its specimen by a factor of 5, surely you meant that we should stock on ammunition now because there may be a shortage in, say, 2 million years?

      January 13, 2011 at 7:10 pm | Report abuse |
  4. Rambo

    Funny that most people who do not believe in Global Warming believe in a God.
    There is more proof of God than Global Warming. That, my friends is the miracle.

    January 13, 2011 at 7:05 pm | Report abuse |
    • MrsFizzy

      There will be people denying it right up to the bitter end.

      January 13, 2011 at 7:08 pm | Report abuse |
    • your friend

      "Funny that most people who do not believe in Global Warming believe in a God.
      There is more proof of God than Global Warming. That, my friends is the miracle."

      are you blind?

      January 13, 2011 at 7:12 pm | Report abuse |
  5. phillip

    there is going on i dont know what but iam going too get too the bottom of it.

    January 13, 2011 at 7:07 pm | Report abuse |
  6. MrsFizzy

    Time to watch The Day After Tomorrow to see what's going to happen...

    January 13, 2011 at 7:07 pm | Report abuse |
  7. Bob Tussey

    Sorry but I have lost all faith in these scientist. I am convinced every word the utter is tied to $$$$$, or political views. But then at 65 years old I have seen again and again how they distort the facts.

    January 13, 2011 at 7:14 pm | Report abuse |
  8. sceptic

    off the top of my head i can think 3 major volcanoes that eruppted in the past year. i think these have a bigger role in the weather patterns then any other cause.

    January 13, 2011 at 7:16 pm | Report abuse |
  9. Arpad101

    The explanation seems quite reasonable from a scientific point of view.

    January 13, 2011 at 7:18 pm | Report abuse |
  10. PartisanSheep

    Well now the skeptics here know. They can't say nobody ever told them.

    January 13, 2011 at 7:18 pm | Report abuse |
  11. T-MAN

    I dont know what this article was actually meant for but i learned absolutly nothing. Im in Cali and the weather sucked all year this last year. Normally you think Cali... Warm, no rain, and beach. It was the exact opposite. The beach was dead because there was always an overcast that didnt burn off until nightfall, and it has rained more this year than any year. Its still cold. Its not dry and warm any where. These smart people need to keep guessing as to what is causing this. Their answers so far suck. Oh yeah and there is hundreds more dead birds in Alabama. Their explination was that they were scared and flew into traffic.

    January 13, 2011 at 7:19 pm | Report abuse |
  12. Arpad101

    Maybe mother nature is a terrorist too or it could be the Pope's fault.

    January 13, 2011 at 7:23 pm | Report abuse |
    • ThisOneTimeAtBandCamp

      Yeah, that's it.

      The pope did it. In the rectory, with the lead pipe and the K-Y.

      January 13, 2011 at 7:35 pm | Report abuse |
  13. The Joe T

    That explanation makes about as much sense as the BS in "An Inconvient Truth". This guy can explain all this but can't figure out what the real high and low temp is going to be tomorrow.

    January 13, 2011 at 7:26 pm | Report abuse |
  14. Travis

    No matter what happens if it gets worse we stand no chance or global economy is the biggest problem (can we say start over or economy is eveery bit as fragile as are globe; what a load)

    January 13, 2011 at 7:36 pm | Report abuse |
  15. noodles

    Its those d@mn butterflies in china

    January 13, 2011 at 7:39 pm | Report abuse |
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