Sep 29, 2015
Heavy rain event as low pressure moved through the Mid-Atlantic ahead of a slow moving cold front. Southerly flow ahead of the low pressure tapped into a moisture rich atmosphere over the Gulf of Mexico. While thunderstorms were isolated due to weaker shear and instability, the heaviest of the precipitation was able to bring down gusty winds from aloft. This also led to flooding across the region.
Source: NOAA National Weather Service Storm Events Database (event 602173). 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.