Flash Flood Guidance
Issued by NWS
Issued by NWS
377 AWUS01 KWNH 242313 FFGMPD VAZ000-NCZ000-WVZ000-TNZ000-KYZ000-250500- Mesoscale Precipitation Discussion 1050 NWS Weather Prediction Center College Park MD 713 PM EDT Tue Sep 24 2024 Areas affected...South-Central Appalachians Concerning...Heavy rainfall...Flash flooding possible Valid 242311Z - 250500Z SUMMARY...Threat for further thunderstorm development overnight ahead of cold front may bring additional 2 to 3" resulting in isolated flash flooding overnight. DISCUSSION...Scattered supercells have developed east of the pre-frontal convection over east-central KY and middle TN in the broad warm sector west of the crest of the south-central Appalachians. Recent rainfall estimates from KJKL are up to 1.5"/hr over far eastern KY. Sufficient moisture of 1.5 to 1.6" PW and instability with MLCAPE 1000 to 1500 J/kg will continue to allow redevelopment of activity this heavy. There are further threats for flash flooding as the main pre-frontal convection comes through later this evening along with topographical lift from the western slopes of the south-central Apps. Deviant motion has been noted from left-moving super cells, so cell mergers and local upwind propagation will continue to be where the greatest flash flood threat is into the overnight. This area has rather low FFG, generally 1 to 1.5"/hr and around 2"/3hr. So overlap from ongoing activity and the next round further raises the potential for flash flooding. Recent HRRR runs have indicated generally 1 to 2" from both rounds, which helps point to an isolated flash flood threat overnight. Jackson ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...GSP...JKL...MRX...RLX...RNK... ATTN...RFC...LMRFC...OHRFC...NWC... LAT...LON 38268090 37298082 36138197 35498348 36318409 37188367 38208261