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.”

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

    @scott: Which is exactly why people shouldn't be adding to the problems. You made a very good point thank you.

    January 13, 2011 at 6:36 pm | Report abuse |
  2. Kachirulo

    If "La Niña" and "El Niño" are doing this mess, I do not even want to know what's going to happen when "El suegro" and "La Suegra" take place, It should be the end of the human being.

    January 13, 2011 at 6:37 pm | Report abuse |
    • Papagino

      Que Bueno Chiste!!!

      January 13, 2011 at 9:34 pm | Report abuse |
  3. FireBad

    The only thing catastrophic about the poles shifting is it's effect on compasses. Plus toilets might flush backwards. Oh and we're all going to DIE! Ahhhhh.....

    January 13, 2011 at 6:38 pm | Report abuse |
  4. Kachirulo

    Niña = Girl, Niño=Boy, Suegra=Mother-in-Law, Suegro=Father-in-Law.

    January 13, 2011 at 6:39 pm | Report abuse |
  5. Bob

    They forgot to mention a third and the REAL reason for the unusual weather patterns.....HAARP. Thanks CNN for not revealing the real truth....again.

    January 13, 2011 at 6:39 pm | Report abuse |
  6. MayanKing

    I think we are going to need more human sacrifices.

    January 13, 2011 at 6:42 pm | Report abuse |
  7. John

    This stuff has been going on for years. But now we all know about because everything these days is news.

    January 13, 2011 at 6:43 pm | Report abuse |
  8. MayanKing

    Yes it's Haarp! I blame the Angels in heaven for this! Grrrr pesky angels!

    January 13, 2011 at 6:44 pm | Report abuse |
  9. Kite005

    The Westboro church will use this in a sermon and claim if proof of what they think. After all, everyone but them is going to hell didn't you know that?

    January 13, 2011 at 6:45 pm | Report abuse |
    • PGR Rider

      To credit westboro as a church is an insult to believers everywhere and of every faith. wbc is simply a self serving publicity hungry group of terrorists.

      January 13, 2011 at 9:37 pm | Report abuse |
  10. ChocolateCaviar

    As long as the Belgian chocolate does not melt, and the Iranian caviar perishes, global weather changes have no impact on me. Life is with a smile lately

    January 13, 2011 at 6:50 pm | Report abuse |
  11. gremlin

    I think waaay too many people on this forum have watched "The Core"

    January 13, 2011 at 6:50 pm | Report abuse |
  12. fineart

    It's stemming from the distorted vibrations that humankind are sending out into the ethers. Their simply returning to the source. They will become more bizarre as the time clock moves ahead. If we change our ways now, we might see a positive change in about thirty years. Laugh if you will, but think about it, talk about it and sleep on it. There has to be some consequence to our thoughs and actions.

    January 13, 2011 at 6:54 pm | Report abuse |
    • Benny V

      yeah... it's all of those negative thoughts and emotions that trap solar radiation and heat up the planet. I read about that in science class. NOT!!

      January 13, 2011 at 9:02 pm | Report abuse |
  13. MayanKing

    God help us all when La Nino and La Nina start bumping and grinding.

    January 13, 2011 at 6:58 pm | Report abuse |
  14. David the Great

    According to Fred Phelps, its the gays.

    January 13, 2011 at 6:58 pm | Report abuse |
  15. MayanKing

    We will sacrifice the gays then yes?

    January 13, 2011 at 6:59 pm | Report abuse |
    • ThisOneTimeAtBandCamp

      UH - no?

      We are currently working on a process that will allow us to procreate amongst ourselves.
      There will soon be no need for the straighties.

      You have been warned.

      January 13, 2011 at 7:33 pm | Report abuse |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30