Wednesday, March 13, 2019

Exciting March Weather


"Superstorm of 1993" Snow in the Mid-Atlantic  (Source: NOAA)
The month of March often produces a high degree of weather variability across the United States.  No place is that more true than in the DC Metro Area.  Longtime Washingtonians know March can pivot from cold and snow to record warmth and severe weather.

Although only 0.3” of snow fell in Washington, D.C. on March 1, it was significant since it made March 2019 the seventh consecutive March that accumulating snowfall has occurred.  While the “coldest” daily average high/low temperatures in the Nation’s Capital are above freezing (51°/34°) on March 1, DC averages 1.3” of snow in March.  To add to that, March has been DC’s snowiest month in four of the last six years.

By coincidence, today is the 26th anniversary of the “Superstorm of 1993” that brought havoc to the eastern United States from Florida to New England.  Record snowfall occurred as far south as Mississippi and Georgia.  The 1993 storm remains the ninth largest snowstorm on record at Dulles Airport in Sterling, VA with 14.1”.  Since the snow changed to sleet at the height of the storm downtown, the overall accumulation in Washington, D.C. was only 6.6”.

Large temperature swings are quite common in March, as well.  For example, DC residents enjoyed a spring-like high temperature of 70° on March 15, 2014, but snow fell the next evening with a high of only 32° on March 17, 2014.  A total of 7.2” of snow accumulated in Washington, D.C. on March 16-17, 2014.

While March 2014 was DC’s snowiest since 1960, March 2012 and March 2016 were DC’s warmest and fourth warmest March’s on record.  Washingtonians experienced four days of high temperatures in the 80s in March 2012 and 10 days in the 70s in both March 2012 and March 2016.  The warmest temperature in the Nation’s Capital so far this March was 62° on March 11.  

Meanwhile, large swings in temperature help create favorable conditions for thunderstorms. While severe thunderstorms aren’t as common in the United States during the month of March as later in the spring, they sometimes occur.  March severe weather is more likely to occur in the southeastern United States as happened in Florida during the 1993 Superstorm.  More recently, a severe weather outbreak on March 3, 2019, produced dozens of tornadoes from northern Florida to South Carolina.  That included a rare EF-4 tornado which caused 23 fatalities in Lee County, Alabama.  

Although infrequent, the DC Metro Area has experienced severe March weather.  On March 10, 2011, two weak tornadoes touched down in northern Virginia.  Just last year, DC residents experienced a powerful wind event as an area of low pressure rapidly intensified as it departed the region.  Consequently, there were some damaging wind gusts that met severe criteria (58 mph/+).  However, gusty winds outside thunderstorms are not officially “severe,” regardless of whether or not any damage occurs.

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