Flash Flood Guidance
Issued by NWS
Issued by NWS
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650 AWUS01 KWNH 300031 FFGMPD FLZ000-GAZ000-ALZ000-300500- Mesoscale Precipitation Discussion 0515 NWS Weather Prediction Center College Park MD 830 PM EDT Sat Jun 29 2024 Areas affected...Far Southeast AL...Southwest GA...FL Panhandle Concerning...Heavy rainfall...Flash flooding possible Valid 300030Z - 300500Z SUMMARY...Additional slow-moving showers and thunderstorms are expected over the next few hours. This coupled with very heavy rainfall rates may foster a few more instances of flash flooding. DISCUSSION...Radar imagery continues to show some slow-moving clusters of heavy showers and thunderstorms across areas of southeast AL and southwest GA with some recent tendencies for the activity to initiate a little bit farther south into the FL Panhandle as well. MLCAPE values remain on the order of 1500 to 2500 J/kg and the PWs are very high with values of 2.2 to 2.4 inches based on the latest GPS-derived data, and this is facilitating very high rainfall rates that are locally on the order of 2 to 3 inches/hour. The flow aloft is also rather diffluent given proximity of the subtropical ridge axis just to the north, and this coupled with the lingering early evening instability and relatively convergent low-level flow should maintain the ongoing areas of convection for a while longer. Some cell-merger activity has been occurring locally, and this coupled with the slow cell-motions overall may yield some additional rainfall totals of 3 to 5 inches going through midnight. This has been advertised by some of the recent HRRR guidance and seems reasonable based on the latest satellite and radar trends. A few additional instances of flash flooding may occur given the high rainfall rates and additional storm totals before the convection weakens later this evening. Orrison ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...JAX...TAE... ATTN...RFC...SERFC...NWC... LAT...LON 31608423 31538345 31198269 30668275 30458341 30468435 30738525 31128541 31438499