Severe Thunderstorm Watch Issued for Washington, D.C., Region; Winds to 70 mph, Large Hail and Possible Tornadoes

The National Weather Service’s Storm Prediction Center issued Severe Thunderstorm Watch 632 on Thursday afternoon for Washington, D.C., and surrounding areas, warning that storms through 10 p.m. EDT could bring damaging winds, large hail and an isolated tornado or two. The watch was issued at 3:15 p.m. and remains in effect until 10 p.m. Thursday, or 2 a.m. UTC Friday.

The watch covers the District of Columbia, central Maryland, northern Virginia, parts of central Pennsylvania, the Eastern Panhandle of West Virginia and nearby coastal waters. For people in the D.C. region, that includes major population centers in and around the metro area, with local National Weather Service notifications covering places such as Montgomery County, Prince George’s County, Anne Arundel County, Arlington, Fairfax and Prince William.

The Storm Prediction Center listed three main threats in the watch. “Scattered damaging wind gusts to 70 mph possible,” the agency said. It also warned of “Scattered large hail events to 1.5 inches in diameter possible” and said, “A tornado or two possible.”

Forecasters said storm coverage and intensity were expected to increase as a shortwave trough and cold front approached from the west. Combined with warm, moist air already in place and strengthening winds higher in the atmosphere, those ingredients were expected to support the development of severe thunderstorms during the afternoon and evening.

A severe thunderstorm watch does not mean severe weather is already occurring everywhere in the watch area. It means conditions are favorable over a broad region for storms capable of producing at least 58 mph wind gusts or 1-inch hail. The Storm Prediction Center, a national forecasting center within the National Weather Service, issues the watch. Local National Weather Service offices then issue warnings for specific storms when radar or spotter reports show an immediate threat.

As the watch was posted, the agency urged residents to stay alert for updates. “REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes.”

Local National Weather Service offices, including the Baltimore/Washington forecast office, were posting related outlooks and issuing storm-specific warnings as needed Thursday afternoon and evening as storms developed across the region.