La Nina this winter: What it is and what it means for our weather

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BRIDGEPORT, W. Va. (WDTV) - You may have hear of El Nino and La Nina, or even the 'southern oscillation'. These are fancy terms to say the water is warmer or cooler than average in the Pacific ocean. Specifically on and near the equator.

We look at sea surface temperatures (SSTs) in this area because they affect global weather patterns. We're talking about the top part of the ocean because this is where it interacts with the atmosphere above. It exchanges heat and moisture with the air. The Pacific takes up a very large portion of the earth's surface and water hold a LOT of heat. The part near the equator is the warmest. So small changes in temperature mean big changes in the overall weather around the globe.

When the water gets warmer than normal, this is called 'El Nino'. When the water gets cooler than normal, this is called 'La Nina'. While changes in temperature occur, the water never gets too cold. The area around the equator has the sun high in the sky through the year. This means it is much warmer than locations far north or south.

The overall difference in temperature on the surface of the ocean here can change by up to 10 degrees Centigrade in each direction. That translates to 18 degrees Fahrenheit. However, the usual fluctuation is not usually this extreme.

These swings of temperature produce big changes in the amount of heat and moisture given off into the air above. This alters the jet stream pattern around the globe. When the jet stream takes different paths, storm systems also take different paths. Storm systems are associated with warm and cold air. Therefore not only is precipitation affected, but also temperature.

If the La Nina forecast holds for this winter, we can expect warmer and wetter than average conditions. This would lead to less snow than we typically receive, with storms favoring rain. However, it will still snow this winter. But totals likely will be under the average. It will still get cold too. But the cold air outbreaks should be less frequent.