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Yo-Yo – An El Nino Winter
(A Report from the WeatherBug)
Over the past 20 years, more and more has been learned about the effects of “El Nino” on global weather patterns. El Nino, which is the abnormal warming of the equatorial Pacific Ocean waters, has been linked to many seasonal weather deviations. In a typical El Nino winter, mild temperatures can be anticipated across much of the United States, wet conditions are often experienced across the southern U.S. and dry conditions are often experienced in the North. El Nino can be measured in various strengths, and the stronger it is, the more likely it is to see these typical effects.
But what if El Nino is not very strong? This winter, El Nino is what can be described as weak to moderate. In years when this occurs, other global changes can play a role. Deviations from normal in pressure and sea surface temperature also have an effect on our seasons. When El Nino is not strong, often there can be shifts in the pattern throughout the winter form El Nino traits to some of these other patterns.
This winter we have seen a couple of switches in the pattern already. The eastern half of the U.S. had been very cold through the end of November and beginning of December, but now the El Nino patterns is dominating with mild temperatures across the U.S. and storms moving into the West and across the South. Further out, towards the end of this month, there are some signs of going back to a colder winter patterns again. Given the strength of El Nino and other global oscillations,” it appears we are in for a “yo-yo” winter where much of the country can expect some mild periods followed by cold and some dry periods followed by wet.
WeatherBug is a great way to watch the changing extremes in weather. Check out Wild Weather in the Main Menu of www.weatherbug.com to see the locations of extreme weather events. Given the track record so far this season, there will be plenty of “Wild Weather” events this winter.
From WeatherBug Chief Meteorologist Mark Hoekzema
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