December 2015 Outlook

Posted: November 30, 2015, 12:00 pm by bmarmo


Image above is the idealized wintertime pattern for a strong El Niños


Welcome to meteorological winter! While December 22nd is the first day of astronomical winter, December 1st is the start of the three month period (December thru February) where we typically see our coldest temperatures. So will the Winter of 2015-16 get off to a cold and snowy start? Right now, all indications say no.

With the strong El Niño approaching record strength, it certainly will be a major player this winter. This is especially true for December, as we are anticipating the emergence of the classic El Niño pattern by the time we enter the second week of the month. Generally, strong El Niños are characterized by an upper level trough of low pressure over the Gulf of Alaska and ridging across much of the northern part of the country. As a result, frigid arctic air is bottled up in central Canada, and mild Pacific air spreads all the way to the eastern seaboard. Not surprisingly, this leads to warmer than average temperatures across the Midwest, Northeast and mid-Atlantic.  

So with El Niño dominating the early portion of meteorological winter, we are expecting an overall mild December across the Midwest, Ohio Valley and East Coast and thus, potentially a slow start for winter. And despite substantial November snowfall in Illinois and Indiana (even some into early December), the last month of 2015 should be relatively quiet in the snowfall department. In fact, this December may end up being similar to last year. December 2014 was not only a mild one, but one of the warmest on record for places along the East Coast. 


Map above shows temperature anomalies (°F) across the US for December 2014

However, this doesn’t mean it won’t snow at all in December. The Great Lakes Region eastward into New England will still have the opportunity to see a few clipper type systems deliver salting events. As for locations farther south, it could be a struggle, as mixed precipitation or even plain rain events will be favored. Thus anybody hoping for a White Christmas in 2015 could be left disappointed. In terms of significant snow, conditions do not look conducive for a big snowmaker as 2015 comes to a close. With that said, we expect the pattern to shift a bit colder with more snow potential as we move into the New Year, especially as we approach February.




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