Flash Flood Guidance
Issued by NWS
Issued by NWS
424 AWUS01 KWNH 141614 FFGMPD GAZ000-ALZ000-MSZ000-142210- Mesoscale Precipitation Discussion 1008 NWS Weather Prediction Center College Park MD 1213 PM EDT Sat Sep 14 2024 Areas affected...northeastern MS into AL and southwestern GA Concerning...Heavy rainfall...Flash flooding possible Valid 141613Z - 142210Z SUMMARY...Thunderstorms are likely to develop across northeastern MS into AL and southwestern GA over the next 3-6 hours resulting in possible flash flooding. Slow moving cells will likely produce 1-2 in/hr rainfall rates, which may overlap with areas that have saturated soils. DISCUSSION...1545Z radar imagery showed lingering rain showers that formed along and east of an elevated convergence axis centered near 925 mb that extended from the southern AL/GA border into northwestern AL. Instability has lowered over northern AL compared to earlier this morning which has allowed rainfall rates to decrease, but small pockets of 1+ in/hr remained via MRMS estimates from eastern AL into far southwestern GA. Visible imagery showed the delineation between overcast skies with ongoing showers in eastern AL and broken cloud cover to mostly clear skies with new cumulus/shower development to the west/south over central/southern AL into northeastern MS. Low level easterly winds are expected to shift the boundary over northern AL to the west through late afternoon while only slow movement is expected to the south. Continued daytime heating should allow weak MLCAPE values up to ~500 J/kg along the northern MS/AL border while higher values in excess of 1000 J/kg expand over central to southeastern AL given clearer skies as seen on visible satellite imagery. A low to mid-level circulation tied to former tropical cyclone Francine was located over northern MS, allowing for a weakness in the steering flow from northwestern MS into GA. Low level convergence is expected to redevelop a bit to the southwest of its current position through the afternoon, though RAP model forecasts are not as strong with the level of convergence compared to earlier this morning. However, given the high moisture environment and slow movement of cells atop saturated soils across portions of the region, a couple of areas of flash flooding may result. Expected rainfall rates of 1-2 in/hr will likely become more numerous into the afternoon from the northern MS/AL border into central/southeastern AL and southwestern GA. Otto ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...BMX...FFC...HUN...JAN...MEG...MOB...TAE... ATTN...RFC...LMRFC...SERFC...NWC... LAT...LON 34998812 34768756 34318712 33128620 32228458 31338442 31018547 31318652 32078766 32658837 33188877 33858915 34588920 34888888