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What is El Niño and How Strong Is It?El Niño occurs when sea surface temperatures (SSTs) in the central and eastern Pacific near the equator are warmer than normal. During October, the SSTs increased nearly a degree with latest weekly average SSTs in the Niño-3.4 region at 1.5C above normal.
There continues to be disagreement among the differerent computer models that forecast the strength of El Niño. The majority do indicate that the three month average Niño-3.4 SST index will remain above 1.0°C through the winter which is considered at least moderate strength. You can find the latest El Niño Advisory and an El Niño FAQ Page on the Climate Prediction (CPC) website. How Will El Niño Effect The Winter in the U.S.?The warmer than normal SSTs typically shift the patterns of the tropical rainfall that in turn changes the strength and location of the jet stream over the Pacific and consequently the continental U.S. This stronger jet stream over the southern U.S. brings increased storminess, more precipitation and cooler than normal temperatures from California to Florida. This pattern also prevents frequent cold air intrusions from Canada resulting in above normal temperatures over the northern U.S. CPC indicates that El Niño will be the dominate factor that will affect the Winter Outlook for the U.S.
How Have El Niños Effected Our Past Winters?Utilizing climatological data dating back to 1950 of previous El Niño years, the trend is for St. Louis and Columbia winters to have near or above normal temperatures. Records at St. Louis indicate that El Niño winters are drier and less snowy, but the statistics from Columbia show a more even spread. Of course weather doesn't always follow climatology and there were two cold and snowy winters during El Niño in the late 1970s.
The following is data from previous El Niño years at St. Louis and Columbia, MO:
Columbia Regional Airport Year Mean Winter Temperature Winter Precipitation Winter Snowfall Total Seasonal Snowfall 1971-2000 Normals 31.2°F 6.40" 18.2" 22.6" 1957-1958 31.4 6.30 18.0 27.0 1963-1964 30.4 2.99 22.0 27.1 1965-1966 33.4 4.74 13.9 14.7 1968-1969 31.0 8.31 12.7 18.1 1969-1970 28.6 1.89 12.8 19.9 1972-1973 30.0 7.46 14.3 25.2 1976-1977 24.6 3.26 32.6 35.0 1977-1978 24.3 3.47 31.9 54.8 1982-1983 36.5 7.69 3.1 4.0 1986-1987 34.7 4.99 21.2 21.2 1987-1988 30.6 9.28 28.0 33.0 1991-1992 37.4 5.20 6.2 13.6 1994-1995 33.0 7.48 25.1 27.3 1997-1998 36.3 7.51 7.6 14.0 2002-2003 30.1 4.36 17.3 18.2 2004-2005 35.5 8.86 6.9 12.1 2006-2007 32.5 6.09 24.1 27.7 # of seasons ABOVE normal 8 6 7 8 # of seasons NEAR normal 7 3 2 0 # of seasons BELOW normal 2 8 8 9 The latest local three month temperature outlook for St. Louis and Columbia that are downscaled from the CPC national outlooks indicate that there is equal chances for above, below, or near normal temperatures for December through February. St. Louis
Columbia Additional local three month temperature outlooks and background information can be found in the climate section of this website. For additional information or questions about how this El Nino may impact eastern Missouri and southwest Illinois, contact: Mark Britt |
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