El Niño Update & Winter Weather Forecast by Livestock WX
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December 15th: Looks like El Niño is finally (almost) here but do we still care?
NOAA recently updated its El Niño forecast and they are giving it an 80% chance that El Niño conditions will form soon and should last through the winter. The reason it has taken so long to form is that the atmosphere is not responding to the warm sea surface conditions in the Pacific Ocean. When these two things sync together it can significantly influence atmospheric circulation and bring us the weather we typically associate with El Niño: which is, a warmer northern tier of the U.S. and a wetter southern tier. Usually, though, El Niño events do not typically form this late in the year and when that happens they do not pack as big an atmospheric punch. The last El Niño event to form this late was in 2003-2004. The images below show what winter precipitation and temperature looked like way back in the early “aughts”. As you can see, precipitation was above normal for most of the southern tier of the U.S. but not completely. Temperatures on the other hand, were above normal for the central U.S. and below normal everywhere else.
This all points to a fairly messy winter forecast scenario. There’s a El Niño but it is forming late in the year and may or may not be able to influence circulation trends already set in motion. The best advice we have is to keep updated on the latest forecast but be a little skeptical on the long-range ones.
OK, time to be skeptical (that was fast) because we have a seasonal forecast for you. It is based on the North American Multi-Model Ensemble (NMME). The NMME is a monthly and seasonal (three month) climate model that can provide a clue into long-range temperature and precipitation anomalies. We like it because it uses several different forecast models taking a consensus of the output. Like my ten-year-old pickup forecast models have strengths and weaknesses. By taking a consensus approach the idea is you are drawing on the strengths of each model which produces a more skillful forecast.
The models (image below) are hinting at a mild winter over the western U.S. and perhaps more typical winter temperatures over the central, eastern and South-Central U.S.
Orange = Above normal temperatures forecast
The forecasts for precipitation are not showing a strong signal for dry weather other than the Pacific Northwest. There is, however, a suggestion for above-normal precipitation over the Southwest and in Oklahoma and the Panhandle in March. That could be good news, BUT, we are a long way out from March and that is an awful long way for a forecast. We will keep monitoring things and bring you latest every week.
Brown = Less precipitation than normal
Green = More precipitation than normal