Weather Blog: La Nina Is Back

MINNEAPOLIS (WCCO) — La Nina, which influenced a rash of extreme weather across the globe over the past year, has re-developed and is forecast to strengthen into the upcoming winter.

The La Nina episode, which began in June 2010 and continued through spring of this year, began to weaken and shift to a neutral phase this summer. However, in August, a La Nina phase began to reemerge.

On Thursday, forecasters with the National Oceanic and Atmospheric Administration’s (NOAA) Climate Prediction Center upgraded last month’s La Nina Watch to a La Nina Advisory.

The La Nina of 2010-2011 was the strongest on record and contributed to record snowfall, severe weather of above-average frequency and severity, and record drought across the United States. Also, there was extreme weather around the world, including devastating flooding in Australia.

La Nina is a climatic phenomenon, originating in the equatorial Eastern Pacific Ocean, during which the sea-surface temperatures cool to temperatures 3-5 degrees Celsius below-average. Changes in global atmospheric circulation patterns accompany this shift.

The cold counterpart to El Nino, La Nina typically occurs every three-to-five years. Back-to-back La Nina episodes occur about 50 percent of the time.

Historically, La Nina winters yield drier than normal conditions across the southern tier of the U.S., and wetter than average conditions in the Pacific Northwest and Ohio Valley. For the north-central states increased precipitation is likely with colder than normal temperatures.

Last year’s La Nina winter in Minnesota yielded the fourth snowiest season on record in the Twin Cities with 86.6 inches. This includes the fifth biggest snowstorm on record in the Twin Cities, which occurred Dec 10-11 and produced 17.1 inches of snow.

  • stubby

    3-5 degrees celcius below average!!!!!!!. Where’s Al Gore and his global warming when you need him? Just when I started to believe all of this global warming hooey, something like this happens. What am I going to do with all of this Copper Tone I bought? Just my luck>

  • jan

    Wasn’t it hot enough for you all summer with record temperatures and dewpoints? You kept your mouth shut then, didn’t you?

  • stubby

    Sure did I loved it. So what happened to all of that heat? Why didn’t all of the co2 keep it trapped and warm that darn ocean so we could have a warm winter? Why is it cooling so much????? Al, explain yourself young man.

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