SMWLWX The National Weather Service in Sterling Virginia has issued a * Special Marine Warning for. Tidal Potomac from Key Bridge to Indian Head MD. * Until 300 PM EDT. * At 153 PM EDT, a strong thunderstorm was located over Alexandria, moving southeast at 10 knots. HAZARD. Wind gusts 34 knots or greater. SOURCE. Radar indicated. IMPACT. Boaters in small craft could be thrown overboard by suddenly higher winds and waves capsizing their vessel. * Locations impacted include. Fort Washington, Fort Hunt, Woodrow Wilson Bridge, National Harbor, and Alexandria.

The areas affected include. Tidal Potomac from Key Bridge to Indian Head MD. At 143 PM EDT, Doppler radar indicated a shower, capable of producing winds to around 25 knots. This shower was located near Alexandria, moving southeast at 15 knots. This shower may develop further into a thunderstorm. Locations impacted include. Fort Washington, Reagan National Airport, Fort Hunt, Woodrow Wilson Bridge, National Harbor, and Alexandria.

* WHAT. Heat index values 100 to 104 expected. * WHERE. Adams, Cumberland, Dauphin, Franklin, Lancaster, Lebanon, Perry, and York Counties. * WHEN. From noon Thursday to 8 PM EDT Friday. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses. Heat-related impacts are likely in some health systems, heat-sensitive industries and infrastructure.