Flash Flood Guidance
Issued by NWS
Issued by NWS
171 AWUS01 KWNH 150507 FFGMPD TNZ000-ALZ000-MSZ000-151105- Mesoscale Precipitation Discussion 1012 NWS Weather Prediction Center College Park MD 106 AM EDT Sun Sep 15 2024 Areas affected...Central to Northwest AL...Far Northeast MS Concerning...Heavy rainfall...Flash flooding possible Valid 150505Z - 151105Z SUMMARY...Heavy showers and thunderstorms are expected to impact areas of central to northwest AL and possibly far northeast MS going through dawn. Given the wet and locally saturated soil conditions, the additional rains going through dawn may result in some additional concerns for flash flooding. DISCUSSION...The latest GOES-E IR satellite imagery shows a couple of regional pockets of cooling convective cloud tops in association with a broken axis of showers and thunderstorms advancing southeast to northwest across areas of central to northwest AL. The convection continues to focus around a broad cyclonic circulation persisting over the Mid-South with an axis of persistent moisture convergence and modest instability in place. MUCAPE values are on the order of 250 to 500+ J/kg. Rainfall rates have been seen increasing a bit over the last 1 to 2 hours with some of the convection that has been coming through the Birmingham metropolitan area, and similar increases in rainfall rates have been noted just west and south of Muscle Shoals. The rates have locally increased to around 1 inch/hour and there has been some additional cell-training concerns noted with both the satellite and radar trends. Notable differences exist in the 00Z HREF guidance with the placement of the additional heavy rainfall threat overnight, but the satellite and radar trends would suggest areas of central to northwest AL, and perhaps far northeast MS will likely be the primary corridor for the heaviest additional rainfall threat. Given some of the cloud-top cooling and cell-training concerns, additional rainfall totals going through dawn may reach as high as 2 to 3+ inches. Given the wet and locally saturated soil conditions, these rains may result in some additional flash flooding concerns going through dawn. Orrison ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...BMX...HUN...MEG...OHX... ATTN...RFC...LMRFC...SERFC...NWC... LAT...LON 35118795 34528698 33628630 33158654 33168741 34118836 34848859