DC’s Severe July Weather

 

NOAA's map of July 25, 2010 severe reports

Although less common than in April, May or June, the DC Metro Area has experienced severe weather in July.  Given the isolated severe weather that’s occurred so far this month, it’s a good time to look at some memorable examples of July severe weather outbreaks.

2022: The DC Metro Area had an active severe weather day on July 12.  Following a typical July afternoon with highs in the 90s and dewpoints in the low 70s, coupled with a high degree of atmospheric instability, there were multiple severe wind and hail reports between 4:00 p.m. and 9:00 p.m.  This outbreak came a week after another outbreak that included two tornadoes.  One tornado touched down in Bowie, Maryland and another occurred in Anne Arundel County, Maryland.  Fortunately, power outages were minimal and no fatalities were reported.

2021: Two confirmed tornadoes occurred within DC city limits on July 1.  An EF-0 with winds of approximately 80 mph was seen near the U.S. Capital.  A second tornado developed in Arlington and tracked across the Potomac into DC.  It was an EF-1 with peak winds of 90 mph during its 4.4-mile path.  The first round of severe weather happened during the peak heat of the afternoon, while the second occurred between 9:00 p.m. and 10:00 p.m. when the tornadoes developed. 

2017:  Several rounds of thunderstorms brought severe weather and flash flooding to parts of the DC Metro Area from July 22 - 24.  The most significant was in Queen Anne’s County in Maryland on July 23.  An EF-2 tornado was on the ground from 1:29 a.m. to 1:33 a.m., with peak winds of 125 mph.  Although the tornado caused appreciable damage to the towns of Bay City and Stephenville, Maryland, there were no fatalities.  A 3-day rainfall total of 2.37” was reported at National Airport.

2013: The month got off to a stormy start in the DC Metro Region with 0.6” of rain at National Airport on July 1.  Severe thunderstorms produced an EF-0 tornado near the town of Brandywine in Prince Georges County, Maryland.  It caused no fatalities and only minor damage.

2010:  A significant heat wave was capped off on July 25 with highs near 100° and an unstable atmosphere.  That’s when a squall line developed west of town and came through the nation’s capital with multiple severe wind gusts.  These storms produced a slew of downed trees and power lines that resulted in widespread power outages, especially in densely populated Montgomery County, Maryland.

NOAA’s criteria for a thunderstorm to be “severe” is when it contains one or more of the following: wind gusts of at least 58 mph; hail 1” in diameter or greater; or a tornado.  While heavy rain and lightning don’t make a thunderstorm “severe” per se, all thunderstorms are potentially dangerous and should be taken seriously.