Jul 8, 2019
A nearly stationary boundary set up near the Potomac River weak low pressure developed along the boundary. There was plenty of moisture in place from the Atlantic and Gulf of Mexico, and this combined with instability to produce very heavy rainfall rates in convection that developed. Convection was maximized around the boundary across central Maryland, and this led to several instances of flooding and flash flooding.
Source: NOAA National Weather Service Storm Events Database (event 835935). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in St. Mary's County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.