Freeze Warnings for much of the DC-Baltimore Corridor (Source: NWS) |
Late October and early November is often when the DC
Metro Region experiences its first freezing temperatures of the fall
season. Such is the case this fall with
the coldest temperatures of the season on tap tonight. Freeze warnings are in effect for much of the
Mid-Atlantic Region tonight and some record lows will be challenged tomorrow morning.
Average low temperatures on November 11 range from 43°
at National Airport to 37° at Dulles Airport.
However, today and tomorrow will feel more like January than
mid-November, with significantly colder than average temperatures. Longtime residents may remember that DC’s
largest November snowstorm occurred on Veteran’s Day 30 years ago.
Fortunately, no snow is expected this weekend and Washingtonians
haven’t had measureable snowfall in November since 1996. The big story this weekend will be the
temperatures. The last time
Washingtonians had temperatures at or below freezing was on March 23, 2017
(30°), while the last time Dulles was that cold was April 9, 2017 (32°). Tonights below freezing temperatures will put
us a few weeks ahead of last year. The
first sub-freezing temperatures at National Airport last fall didn’t occur
until November 23, 2016 (32°). However,
Dulles Airport was 30° on October 26, 2016.
There is often several weeks’ difference between when
the first subfreezing temperatures occur at National vs. Dulles Airports. That can be attributed to the local geography
as National Airport is located adjacent to the moderating influences of the
Potomac River, as well as downtown. The
“urban heat island effect” often keeps urban areas warmer than suburban or
rural areas. Although the Dulles
corridor is more developed than 20 to 30 years ago, it’s still significantly
more rural than National Airport and away from the Potomac River.
While weather records for Washington, D.C. date back
to 1871, Dulles Airport didn’t open until 1960.
No record lows have been set at National Airport in November since
1976. However, Dulles Airport has had
five record lows in November just since 2003.
November
11 Record Low Temperatures
Washington, D.C. (National Airport –
DCA): 26° (1973)
Dulles Airport, Sterling, Virginia: 16° (1973)
Baltimore, MD (BWI Airport): 21° (1973)
Dulles Airport, Sterling, Virginia: 16° (1973)
Baltimore, MD (BWI Airport): 21° (1973)
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