May 5, 2019
Low pressure tracked along a stalled boundary, passing through the area overnight on the 4th into the 5th. The lift associated with the low and the boundary combined with high amounts of moisture from the Atlantic Ocean and Gulf of Mexico, bringing heavy rain to the area. The rain led to several instances of flooding.
Source: NOAA National Weather Service Storm Events Database (event 824964). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Frederick County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.