El Nino and this upcoming winter

El Nino and this upcoming winter

El Nino and this upcoming winter

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by Kristin Walls

WHAS11.com

Posted on October 2, 2012 at 8:01 AM

Updated Tuesday, Oct 2 at 8:13 AM

Remember the terms El Nino and La Nina? Well, one of them will influence the upcoming winter. According to NOAA’s Climate Prediction Center (CPC), weak El Nino conditions may develop this fall.

But, what exactly are El Nino and La Nina?  El Nino is characterized by unusually warm temperatures and La Nina by unusually cool temperatures in the equatorial Pacific.  Even though this occurs far away, it can have a dramatic effect on world weather patterns.
A typical La Nina winter will feature drier and milder conditions across the South, much like we had last winter. The Pacific Northwest will become wetter than normal, while the Northeast will have cold periods, but these are usually short lived.
A typical El Nino winter will feature stormy winters in the Northeast and milder winters in the Northwest.
Take a look at the maps below from the CPC. These maps show the difference from average December through February temperature and precipitation averaged over 22 El Nino and 19 La Nina episodes that have occurred in the past 60 years.
Since the CPC says weak El Nino conditions may develop this fall, pay attention to the maps on the left. The top left map shows temperatures. Shades of blue indicate temperatures 3 degrees below average with shades of red 3 degrees above average. The bottom left shows precipitation. Shades of brown indicate areas that received up to 2.5 inches less than average precipitation while green indicates up to 2.5 inches more than average.
If we have weak El Nino conditions this fall, we could have a colder and drier winter this year.

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