Jul 18, 2019
A wave of low pressure riding along a stalled frontal boundary resulted in isolated flash flooding in Nassau County. These storms developed within a moisture-rich environment with slow storm motions, and came after widespread 1-2 inch rainfall totals the day before. Precipitable water values from the Upton, NY sounding ranged from 2.25-2.5 inches during the event.
Source: NOAA National Weather Service Storm Events Database (event 848572). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Nassau County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.