Warmest and Driest February?

This month will finish as the warmest February and among the driest on record in the Nation’s Capital.  In addition to the slew of record highs that have been set this month in the DC Metro area, Washingtonians have experienced 70-degree warmth in both January and February for the first time since 2008.  

Much to the chagrin of snow-lovers in the Nation’s Capital, February had the second highest total number of days in the 70s on record with six.  That’s just behind the 1976 record of seven days, which holds the existing record for warmest February in Washington, D.C.  How is it possible for this month to be warmer with fewer 70-degree days?  That can be explained largely by warmer overnight low temperatures this February compared to 1976.

There has been a lot of urbanization and development in the DC Metro Region since the 1970s, which enhances the “urban heat island effect.”  That helps keep temperatures warmer at night than in a more suburban or rural areas.  There were only eight days with temperatures at or below freezing this month in the Nation’s Capital.  That’s compared to a total of ten days with high temperatures of 60 degrees or warmer.

National Airport set two record high temperatures this month as well as four record high-low temperatures.  No measureable snowfall occurred in Washington, D.C. this February for the first time since 2004.  Meanwhile, Dulles Airport experienced similar conditions this month with three record highs and five record high-low temperatures.  In fact, the high temperature reached 77 degrees at Dulles on three consecutive days starting February 23, while it was only 77 degrees once this month at National Airport.  Such temperatures are more characteristic of Memorial Day than President’s Day.

National Weather Service data shows that the 2016-2017 winter (defined as the months of December, January and February) is poised to finish as the third warmest winter on record in Washington, D.C. – and warmest since 1931-1932.  This winter will likely be the warmest on record at Dulles Airport.  

Whether this month finishes as the first or second driest February is less important than the fact that the Nation’s Capital has an ongoing rainfall deficit of 13.27” dating back to August 2015.  There has been below average monthly rainfall in 15 of the 18 months since then, with a rainfall deficit of 2.69” just since December 1, 2016.

Weather Quiz

True or False.  This February’s average temperature in the Nation’s Capital is warmer than March’s average monthly temperature.

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Answer to February 16 Weather Quiz question.

C.  Six of the Top 10 snowstorms on record in the Nation’s Capital have occurred in February.  The most recent of these February snowstorms was Presidents’ Day 2003 when 16.4” of snow fell at National Airport – tied for ninth largest on record.  Two other February storms are tied for 10^th largest snowfall (14.4”).

Severe Weather ?

NOAA's Severe Weather Outlook for February 25

A powerful cold front will usher significantly cooler temperatures into the Mid-Atlantic Region.  Showers and thunderstorms will occur this afternoon in the DC Metro area.  However, Washingtonians have already enjoyed another day of unseasonal warmth with temperatures in the mid-70s – more characteristic of mid-May than late-February. 

Tomorrow’s high temperatures will be much closer to average in the upper 40s and low 50s across the DC Metro area.  Such dramatic swings in temperature can contribute to severe weather as highlighted below.

February 12, 2017: Another significant cold front passed through the eastern United States and brought with it some impressive wind gusts.  Although there weren’t any thunderstorms in the DC Metro area with this cold front, wind gusts did reach severe criteria in spots, such as National Airport which had a wind gust of 65 mph.  Dulles Airport saw a wind gust of 58 mph.  A thunderstorm that produces wind gusts of at least 58 mph is “severe.”  While these winds weren’t technically “severe” because the gusts didn’t occur in a thunderstorm, they did cause downed trees and power lines.

  

February 24, 2016: Last February, a more traditional outbreak of severe weather occurred.  This was a well-forecast episode of severe weather that brought the DC Metro area severe wind gusts which resulted in damage reports around town.  Unlike earlier this month, these wind gusts met the textbook definition of severe weather because they occurred during thunderstorms.  Tornadoes were also reported from Pennsylvania to Florida.
  

March 10, 2011:  Although this severe weather outbreak occurred in early March, it is included in this column since two tornadoes occurred locally.  One in Fairfax County and another in Fauquier County – both in northern Virginia.  Fortunately, there were no injuries and only minor damage was reported.

  

February 11-12, 2009:  A severe weather outbreak occurred on February 11, 2009, with damaging wind gusts.  High winds remained after the cold front had passed through the Mid-Atlantic Region on February 12.  Wind gusts between 50 and 60 mph were common in the DC Metro area, with gusts of 52 mph at National Airport, 65 mph in Rockville, MD, 60 mph in Leesburg, VA and 71 mph in Martinsburg, West Virginia.  Although not technically “severe” since they didn’t occur during thunderstorms, these winds did cause isolated power outages and downed trees.