May 20, 2021
A deep longwave trough remained anchored over the Central and Southern Rockies on May 20th, with a deep southerly fetch of low level moisture continuing to maintain an ample moisture-rich environment over the Four State Region. Diurnal heating contributed to air mass destabilization during the afternoon, with disturbances aloft contributing to scattered shower and isolated thunderstorm development across the area. Low level shear increased during the afternoon, and helped foster the development
Source: NOAA National Weather Service Storm Events Database (event 952539). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in McCurtain County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.