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. Penone

    I have a theory for why these weather changes are happening. It is a phenomena that happens every 3 months. I call it Winter, Spring, Summer, Fall.

    January 14, 2011 at 2:15 pm | Report abuse |
  2. john121

    Peggy, serously, 'heavier water'?!? There is heavy water but it is something ENTIRELY different. Used to make the atomic bomb. A glass of ice water weighs the same after the ice melts. This is why we have a problem people.. We have people who think they are smart who are doubting actual smart people who are telling them that Global Warming is happening!!!

    January 14, 2011 at 2:19 pm | Report abuse |
  3. The Bodacious

    I procreate the weather. Have fun today for it will snow somewhere in the world you wizards!

    January 14, 2011 at 2:22 pm | Report abuse |
  4. obviously

    Sarah Palin's fault

    January 14, 2011 at 2:23 pm | Report abuse |
  5. Wrangler Wayne

    Actually, a very nicely done article. it's spot on as they say down under. But nevertheless, we are in a Landscheidt
    solar minimum. This is close to an identical repeat of the Dalton Minimum in the 1800s. Climate will similarly cool for the next few decades. There is a twist. A new theory predicts that sunspots will wink out when the sun's gauss drops below 1500 around 2016. If this happens, will this solar cycle 24 then initiate a more severe Maunder like minimum? Keep an indirect eye on the sunspots folks!

    January 14, 2011 at 2:33 pm | Report abuse |
  6. voiceofreason1

    We all know what is behind this bizzare weather. Al Gore...right CNN?

    January 14, 2011 at 2:33 pm | Report abuse |
  7. Phil

    Kevin –
    Kevin lets recap – what do trees, plants and oceans expel (breath out). YEP CO2. Also Please explain away the "ring of fire" AKA the pacific rims ring of thousand of volcanoes? Explain, how more green house gases can be expel by these volcanoes in a few year then all the CO2 man has expel since the being of made kind – and then say man is a affecting it more than is natural cycles?????. It's like saying a tumble of hot water can raise the tempture of a bath tub of water.
    You people should be more worried about something you can do some thing about that is undisputable – air, water polution.

    January 14, 2011 at 2:38 pm | Report abuse |
    • jt

      Phil... Let's re-recap. What does plant life expel - O2, not CO2!

      January 14, 2011 at 2:41 pm | Report abuse |
    • john121

      jt... while i totally agree with your comment and Phil is clearly one of the people I was talking about, were you not just a little condescending there yourself? Hi Pot, my name is Kettle. Yep, you nailed it, we're both black, Its nice to meet you 😉

      January 14, 2011 at 3:07 pm | Report abuse |
    • YetAnotherBob

      @jt, plants do expel CO2 at night. during the day they make sugar out of CO2 and oxygen. at night, they use the sugar and expel CO2.

      Animals do all the time what plants do at night. Fungus does what animals do. Biology is fun, you should try it.

      January 14, 2011 at 7:58 pm | Report abuse |
  8. Dean

    Hahaha. I love the global warming back-and-forth.

    "It's a natural cycle. It's been going on for millenia. Global warming is a farce"
    "Hey, 8 of the last 10 years are the hottest on record!"
    "We haven't been keeping records for very long, and those we have were falsified"
    "Uh – so how can you say it is a natural cycle if we don't know what previous temperatures were?"

    January 14, 2011 at 2:38 pm | Report abuse |
  9. JP

    On behalf of the United States, Thank You Florida for your hanging chads in 2000. Al Gore is wrong again. Although...I would take some of his "global warming" right about now. However, for now, "Global Warming" remains to be nothing more than a Twilight Zone episode, which if you listen to Mr Gore, is where he seems most comfortable. Maybe he can run for Prez. there when they have their next election.

    January 14, 2011 at 2:40 pm | Report abuse |
    • john121

      Where are you getting your facts? Are you just making unscientific observations? The extreme winters ARE a part of global warming. Please, do some research instead of just assuming that because the name of the theory is Global WARMING the theory means everything will be warmer. Ugh...

      January 14, 2011 at 3:34 pm | Report abuse |
    • YetAnotherBob


      Does this mean that you agree with Hollywood in "day after tomorrow" that Ice is formed by heating water? When I studied Thermodynamics in College, that wasn't how the professor explained it.

      January 14, 2011 at 8:02 pm | Report abuse |
  10. Arpad101

    The third phenomenon responsible for the world's bizarre weather is the internet.

    January 14, 2011 at 2:47 pm | Report abuse |
  11. Bill

    I thought Obama was your savior, Libs? Da...Yes we can. Da.....Yes we can

    January 14, 2011 at 2:56 pm | Report abuse |
  12. JESUS

    The weather is changing from one extreme to the other. Something seriously happening that the scientists have no clue.

    January 14, 2011 at 2:58 pm | Report abuse |
  13. David

    Why can't weather forecasters just say they don't have an f***in clue why the weather is the way it is. Face it folks, predicting the weather is just like predicting the economy or predicting who will win the Super Bowl. Everytime a weather event happens, experts try to explain it, but there is no consistency in the explanation. La Nina / El Nino, it's all BS.

    January 14, 2011 at 3:04 pm | Report abuse |
  14. Mr. Global Warmer

    Arctic ice melt and shrinkage is what is causing these irregular disturbances, more cold air moving south from the Arctic Pole, meets warming air from South = snow storms! Doh!

    January 14, 2011 at 3:05 pm | Report abuse |
    • YetAnotherBob

      Ice melt implies a warmer Arctic, not a colder one. Less reflectance.

      January 14, 2011 at 8:05 pm | Report abuse |
  15. HardityHar

    That image looks like it was created by an Apple IIe in 1983.

    January 14, 2011 at 3:07 pm | Report abuse |
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