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. Billy Jr.

    KNKLHEAD, you are a KNKLHEAD.

    Still believe in Obama, too, you silly Lib?

    You Libs sleigh me more every day.

    January 14, 2011 at 10:51 am | Report abuse |
  2. Sri

    WE ARE IN VIKRUTHI YEAR AS PER THE HINDU CALANDER. THIS YEAR WILL END IN APRIL 3, 2011. PRAKRUTHI MEANS NATURE AND UNIVERSE. VIKRUHTI IS OPPOSITE OF PRAKRUHTI WHICH MEANS DISTRUCTION OF NATURE AND UNIVERSE. PRAY GOD, CHANT GOD'S NAME, ALWAYS DO GOOD THINGS, DESTROY EGO, HELP POOR AND FEED THE HUNGRY. THOSE WHO DOES GOOD DEEDS WILL ALWAYS BE PROTECTED BY GOD. IT IS ALL KARMA. IF YOU DO GOOD, YOU OR YOUR KIDS WILL REAP THE BENIFITS. IF YOU DO BAD, YOU HAVE TO PAY FOR THE SINS. UNTIL APRIL 3, 2011, IT'S ALL KARMA. PLEASE THIS IS NOT A JOKE AS I HAVE MET GOD WHEN I WAS 17 IN INDIA. I ALWAYS PRAY GOD FOR THE WORLD PEACE AND WELL BEING OF ALL HUMAN BEINGS AROUND THE WORLD. SOME OF MY PRAYERS SAVED PEOPLE FROM DEATH BED AND CANCER.

    LET PEACE BE BESTOWED UPON ON ALL HUMAN BEINGS AROUND THE WORLD.

    January 14, 2011 at 10:52 am | Report abuse |
  3. anonymous

    I don't understand what is so "bizarre" about this weather. Weather has been extreme since the earth was formed. There have been floods and snow blizzards since way before the dawn of human recorded history. The only "bizarre" thing about it is all the people freaking out over it. It happens. Deal with it.

    January 14, 2011 at 10:56 am | Report abuse |
  4. Bud

    And all along I thot it was BUSHS' fault !!

    January 14, 2011 at 11:00 am | Report abuse |
  5. anonymous

    Obsessing over a number causes that number to become an obsessive fascination in your subconcious. The more you obsess over it the more you will notice it. Try a different number. 123. It works. Honest. It's just random coincidences and you've trained your mind to focus on that number. Unfocus.

    January 14, 2011 at 11:00 am | Report abuse |
  6. shibbygirl

    El Nina is Spanish for.... the Nina!!!

    January 14, 2011 at 11:00 am | Report abuse |
  7. SteveB

    Oy, yi, yi. People, it's called 'weather'. Nothing unusual that there is snow, wind, rain, floods. If we had a big snowfall in July, that would be news. I just drove past the Delaware River and it looks exactly like that famous painting of George Washington crossing the Delaware. I guess ice floes and snow happened then too.

    January 14, 2011 at 11:01 am | Report abuse |
  8. Bud

    It's BUSHs' fault !!

    January 14, 2011 at 11:01 am | Report abuse |
  9. Jason

    It took me a ton of research, looking over extreme amounts of data, and many sleepless nights to figure out what is happening...

    I final concluded this...

    It's called winter.

    January 14, 2011 at 11:02 am | Report abuse |
    • Catie

      hahaha, very cute

      January 14, 2011 at 2:07 pm | Report abuse |
  10. Linda

    OK, Mother Nature is in control. May the human race never learn to control the weather!!! As catastrophic as it can be, we would mess it up and ruin more of this beautiful, mysterious small globe we exist on for a very short time. All have a Happy New Year and Take Care Of Mother Earth.

    January 14, 2011 at 11:03 am | Report abuse |
  11. Truthseeker07

    HAARP project and Geoengineering is the reason for all of this, including the dead birds and fish.

    January 14, 2011 at 11:06 am | Report abuse |
  12. mizh

    NOT global warming — CLIMATE CHANGE. People are SO STUPID.

    January 14, 2011 at 11:09 am | Report abuse |
  13. Rum Dumb

    Bush's fault.

    January 14, 2011 at 11:13 am | Report abuse |
  14. Norse1990

    Global climate change is pretty much a proven fact. Sadly most people don't understand the difference between weather (short-term) and climate (long-term). The reports we have been seeing this winter are related to weather and there can be huge variations in weather patterns in a given climate.

    January 14, 2011 at 11:15 am | Report abuse |
  15. dumdum sucker

    Aside from the Chris Farley post, this thread (and CNN generally) is a complete waste of time punctuated by sloppy grammar and an absence of analytical thinking.

    January 14, 2011 at 11:15 am | Report abuse |
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