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. Cold War Veteran

    I think CNN did a good job with this report. They explained a very complicated set of interacting processes in a way that was clear and understandable to me. By the looks of some posts, there still are some folks who seem completely baffled by it. I think most of these folks will get it eventually, one way or another.

    January 14, 2011 at 1:09 pm | Report abuse |
  2. I just want to know

    If this weather is the 'new normal' or not for the American South. Atlanta got 4" of snow last Sunday and was pretty much shut down for five days.

    If Georgia has storms like this, there is a great business opportunity for road-deicing equipment suppliers and makers of cable-chains for cars.

    Maybe some clever inventor who can find a way to convert Kudzu into an effective ice-melting solution.

    January 14, 2011 at 1:15 pm | Report abuse |
  3. Like that

    Jeshua was His name in Hebrew. it went latin to Jesus after His death and ressurection.

    January 14, 2011 at 1:15 pm | Report abuse |
    • YetAnotherBob

      Yeasu in Aramaic, the spoken language of the times in Judea. Hebrew was reserved for Church.

      Jesus is a Greek transliteration, not Latin. Latin didn't become the language of the Western Church until around 400 AD. The Roman Empires written correspondence was in Greek. Latin for anything but street talk came later. Greek scribes and slaves did most of the paperwork in Rome.

      Ignore the preachers, talk to Archeologists to find out what really happened.

      January 14, 2011 at 7:21 pm | Report abuse |
  4. Jeap

    Well this all seems a little... well how should i say this? uhhh well "uhm uhm" <- this is how experts react when asked for simple answers about climate change. Why may you ask? they love their jobs! Please Capital hill dont come out with another project "blue book" related to climate change and hide the truth cause i really dont care if 2012 is the end of time. i'd much rather all of us die at once singing "kumm bye yahh" or what ever then from war or worse a zombie infection!

    January 14, 2011 at 1:16 pm | Report abuse |
    • sonofgadfly

      Why do experts hesitate when asked for simple answers about Climate Change? Because it's a complex subject, and no one yet has succeeded in dumbing it down enough to be understood by all the burger-flippers out there. Besides, even if some expert were to provide a clear explanation in 2 minutes or less, someone would find a way to make a completely misleading five-second sound bite from it.

      January 14, 2011 at 2:20 pm | Report abuse |
  5. qriusme

    I believe Polar Shift is the cause:

    January 14, 2011 at 1:17 pm | Report abuse |
  6. HavPlenty

    I'm not sure why it's hard to believe that this weather is abnormal and can't be biblically related. You can bring up other record temps from other years and so forth. But never have we had such constant disasters back to back to back. Something crazy is happening almost EVERYDAY now. And that's just weather...let's not even get into other crazy current events. What took place in Tucson is something I'm VERY used to hearing the Middle East. Open your eyes a little wider. The Bible is real!!!!

    January 14, 2011 at 1:22 pm | Report abuse |
    • jt

      We have not had the REPORTING of occurrences so often. They have always happened, just not placed on CNN each and every day!

      January 14, 2011 at 1:46 pm | Report abuse |
    • HavPlenty

      It doesn't matter if CNN posted them daily or not. If this were happening this often in the past, people would have pulled that data up anyway for discussions like these long ago. We just need to live without the blinders. Just because a lot of us believe this stuff is biblical, doesn't mean we want to be surrounded with constant destruction. But to believe these things are just coincidental is just denial. I can see if 48 or 49 states had snow at once one year, a lot of fish and birds died 2 years ago, floods 5 years...etc. This isn't the case...rapid change in weather and other global issues. You just wait and watch. There's more to come.

      January 14, 2011 at 2:20 pm | Report abuse |
  7. Michael

    @Americaneedsrealists ... IMHO, anyone that denys mankind's impact on Earth's climate has their bloody head in the sand and it is intuitively obvious even to most casual observer from whence your news comes from. Can anyone truly deny the loss of the Ross Ice Shelf or of many northern hemisphere glaciers? That ice was over 10,000 years old, folks. So why would it all just suddenly up and disappear? Not in the past 150 years, but in the past TEN?? CO2 is just one of the many greenhouse gasses that are causing problems. Yes, Methane is part of the problem as well and can be delat with in a logical manner. But back to CO2 ... two thoughts: conservation (green roofs, efficient transportation) and PLANT TREES. One impact of mankind that apparently goes unnoticed is our rapid deforestation of the planet – an act that has contributed significantly to our current situation. Across the US and the world, if you're not using the land to produce, PLANT TREES !! One last thought – "Global Warming" is a misnomer; the true phrase should be "Adverse Climate Change". Period. End Of Line ...

    January 14, 2011 at 1:22 pm | Report abuse |
    • YetAnotherBob

      Loss of the Ross Ice Shelf, which time???

      January 14, 2011 at 7:25 pm | Report abuse |
  8. iceman

    Now that's what I call: A DEEP FREEZE!

    January 14, 2011 at 1:22 pm | Report abuse |
  9. jay

    I find the human hubris facinating and amusing at the same time. I am not Atheist, but Jesus, nor the Mexican Gardner, nor global warming have anything to do with the natural occurance of weather patterns on the earth, in fact, we prove that we are powerless to control it daily, or else, we would control it.

    IT will come, it will go, and we will continue to believe daft dolts like AL Gore cause he said so...

    January 14, 2011 at 1:31 pm | Report abuse |
  10. John-O

    A little Off topic, BUT, Did You Know Ricky Martin Is Gay?

    January 14, 2011 at 1:32 pm | Report abuse |
  11. me

    and next year will be a lot worse.

    January 14, 2011 at 1:33 pm | Report abuse |
  12. whitespatula

    Jesus is coming! Everyone look busy!

    January 14, 2011 at 1:35 pm | Report abuse |
  13. Jose

    My great great great great great great great great great great great great great great great great great great great great great great great great great great great great great great great great great great Grandfather was a Mayan and he said that Dec 12, 2012 is gonna happen so everybody:


    January 14, 2011 at 1:36 pm | Report abuse |
    • YetAnotherBob

      That day, the fifth cycle ends, and the next day the sixth cycle begins. So what.

      It's all based on the transit of Venus.

      January 14, 2011 at 7:28 pm | Report abuse |
  14. Catie

    I have a crazy idea. Maybe this is just supposed to happen. For man, have you seen how teeny tiny man is from outer space, to have the arrogance the he is responsible for the atmospheres behavior is humorous. If there is a God, then God planned for the adjustment of man, if there is no God, then I would hope that just by the mere size of the galaxy that our little puny vehicles and factories would not have an effect. Man is so conceited, I swear

    January 14, 2011 at 1:39 pm | Report abuse |
  15. jt

    How about it's weather. The earth travels through space and gets hit by solar radiation and it heats up the atmosphere in some places and cools down in others. Can't control it, for the most part can't predict it except in the short term. Get a grip folks.

    January 14, 2011 at 1:41 pm | Report abuse |
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