Does November’s Chilly Start Predict a Cold Winter ?

 

 

The cool start to November may feel especially chilly considering how warm October was.  D.C.’s coolest October temperature was a relatively balmy 47° on the 19^th, with eight days in the 80s.  By comparison, this month has already had four consecutive cooler than average days.

Although next week will be warmer than average in the D.C. Metro Area, some may wonder whether a colder than average November foreshadows what the upcoming winter season will be like.  There have been some winters when November’s weather in the Nation’s Capital did, in fact, do that.  Such was the case during the 1995-1996 winter season.  November 1995 was 6.5° colder than average in Washington, D.C. with 0.5” of snow.  As longtime Washingtonians may recall, 1995-1996 was DC’s third snowiest winter on record with a total of 46”.  That winter season was also 2.9° colder than average and occurred during a moderate episode of La Nina.

On the other hand, November 2009 was 2.6° warmer than average in Washington, D.C. and gave way to what became DC’s snowiest winter.  A total of 56.1” of snow fell in the Nation’s Capital during the 2009-2010 season, which broke the previous record of 54.4” from 1898-99.  The 2009 - 2010 winter was also 2.4° colder than average.  However, unlike the 1995-1996 La Nina winter, it featured a moderate intensity episode of El Nino.  One of El Nino’s hallmarks is an active southern branch of the jet stream that can play a key role in coastal storms during the winter.

More recently, November 2018 was 3.1° cooler than average.  It was also the first time accumulating November snowfall occurred in the Nation’s Capital since 1996.  A weak El Nino was present for the 2018-2019 winter season that finished 1.3° warmer than average.  There was one significant winter storm during 2018-2019 with 10.3” of snow at National Airport from January 12 – 14, 2019.  Absent that snow event, however, the 2018-2019 winter would have finished with only 6.6” of snow.  That’s less than half of what the Nation’s Capital averages during a typical winter

These examples illustrate that while November’s weather sometimes serves as a harbinger of what the upcoming winter might be like, no accurate conclusions can be drawn based on it.  There are simply too many variables to rely solely on November weather as a predictor.  NOAA’s Climate Prediction Center expects this month to feature above average temperatures with near to above average rainfall.  La Nina conditions have also developed and are expected to continue through the 2021-2022 winter season.