AWUS01 KWNH 172233 FFGMPD NYZ000-PAZ000-MDZ000-WVZ000-OHZ000-180400- Mesoscale Precipitation Discussion 0160 NWS Weather Prediction Center College Park MD 633 PM EDT Wed Apr 17 2024 Areas affected...eastern OH, WV, MD Panhandle into western PA and far western NY Concerning...Heavy rainfall...Flash flooding possible Valid 172232Z - 180400Z Summary...The potential for a quick inch or two of rain may produce localized flash flood concerns across portions of the Appalachian Plateau into the central Appalachians through 04Z. While total rainfall is not expected to amount to much, the region contains above average soil moisture and elevated creeks/streams from heavy rainfall within the past 2 weeks. Discussion...22Z radar imagery across the Upper OH Valley showed a band of thunderstorms located along and ahead of a cold front moving through east-central OH. Farther east, thunderstorm coverage was in the process of expanding near a stationary front that extended from NW to SE across western PA. The warm sector was characterized by MLCAPE of 500 to over 1000 J/kg as seen on the 22Z SPC mesoanalysis, confirmed with the 21Z PBZ sounding, although instability in WV was still below 500 J/kg with the cold front still well west of the region. Several Wunderground.com observing sites have reported 0.5 to 1.0 inches of rain in 15 minutes with the line of thunderstorms as they've moved through over the past 1-2 hours, but the forward progression of the cold front has limited total rainfall to 1 to 1.5 inches in localized spots across the area. Given mean steering flow from the WSW and a tendency for the line of thunderstorms, south of the apex, to align with the mean wind, training potential has increased for some locations in central to southeastern OH. MLCAPE of about 500 to 1000 J/kg is forecast by the RAP to advance eastward with the progression of the cold front and some weak instability will remain after sunset, especially across WV where 0-2 km moisture is expected to remain highest relative to northern locations. Additional thunderstorm development will be possible near/south of the southern edge of the existing line as it moves into WV with possible short term training resulting in high rainfall intensities over a time frame of up to 1-2 hours. Northern locations from west-central PA into western NY may experience two rounds of heavy rain, first with the ongoing discrete cells and second as the front approaches from the west after 00Z. The region from eastern OH into western PA and WV has received 4-8 inches above average rainfall over the last 2 weeks, leaving portions of the area with increased soil moisture and elevated waterways. A quick 1-2 inches of rain may result in localized flash flooding through the early overnight. Otto ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...BUF...CLE...CTP...ILN...LWX...PBZ...RLX... ATTN...RFC...MARFC...NERFC...OHRFC...NWC... LAT...LON 42517894 42277803 41247762 40127798 39597849 38308010 38228151 38328192 39018300 39668308 40498196 41828134 42307991