Will October’s Warmth Influence November?

Fall Foliage in Shenandoah National Park, VA
(Courtesy: Mallory Hughes @mallorymhughes)

October 2016 was one of the warmest and driest on record.  With a monthly average temperature (combining daily highs and lows) of 63.1 degrees at National Airport, last month was the tenth warmest October on record and warmest October since 2007.  October 2016’s warmest temperature occurred on the 19^th when it was 87 degrees (more characteristic of mid-August).  

October 2016 was also drier than average in Washington, D.C. with only 0.9” of rain (2.5” below average).  That made it the driest October in the Nation’s Capital since 2001 (0.69”) and one of the driest overall dating back to 1871.  The unusually warm and dry conditions that dominated October’s weather headlines in the Mid-Atlantic Region have acerbated the existing rainfall deficit.  That’s led to a small area of “moderate” drought conditions in Loudoun County, Virginia according to the latest Drought Monitor Index.

The warmer than average weather is poised to continue into November.  Although NOAA’s Climate Prediction Center said there is an equal probability of above or below temperatures over the first half of November, it predicts a 40% chance of above average monthly temperatures in the DC Metro Region for the entire month.  Temperatures will feel more like late September or early October today and tomorrow, with temperatures in the mid to upper 70s in the Nation’s Capital.

The average high and low temperatures in Washington, D.C. on November 1 are 63 and 45 degrees and fall to 52/37 by November 30.  November’s record high temperature in the Nation’s Capital is 86 degrees (November 1, 1974), while November’s lowest temperature is 11 degrees (November 30, 1929).  Washingtonians see an average of 3.17” of rain in November as well as 0.5” of snow.  November is the first of five consecutive months that averages measureable snowfall at National Airport (Washington, D.C.’s official weather reporting site).  However, no measureable snow has occurred in the Nation’s Capital in November since 1996.

Some may remember Washington, D.C.’s largest November snowfall was on Veteran’s Day in 1987 (11.5”).  However, a significant amount of cold and snow in November and/or December doesn’t necessarily foreshadow what the entire winter will be like.  For example, following the warmest December on record in 2015, the first measureable snowfall of last winter didn’t occur until January 17.  Despite that late start, last winter ended up being snowier than average.  NOAA recently issued its national winter weather outlook for the 2016-2017 season.  My colleagues and I on the WUSA9 Weather Team will issue our winter weather outlook next Monday, November 7.