Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Apr 13 2023 08:19:50 AWUS01 KWNH 130819 FFGMPD FLZ000-ALZ000-MSZ000-131218- Mesoscale Precipitation Discussion 0182 NWS Weather Prediction Center College Park MD 419 AM EDT Thu Apr 13 2023 Areas affected...coastal areas of Alabama and the western Florida Panhandle Concerning...Heavy rainfall...Flash flooding possible Valid 130818Z - 131218Z Summary...Scattered bands of convection will migrate northward in tandem with a low over the north-central Gulf of Mexico. These storms could produce locally heavy rainfall and excessive runoff - especially in low-lying and/or urbanized areas. Discussion...Deeper convection has emerged just north through northeast of a surface low across the north-central Gulf of Mexico located approximately 100 mi. southeast of BVE. Objective analyses and observations suggest that a narrow band of moderate instability (approx 1000-1500 J/kg MLCAPE) has materialized on the north side of the low, as evidenced by 72/70F observation at KVOA in the last hour and lightning/cooling cloud tops with cells 50-60 miles south-southeast of Mobile, Alabama via lightning/satellite imagery. The convection will likely translate northward in tandem with northward movement of the surface low and axis of instability just to its north, reaching coastal portions of the discussion area beginning after 0830Z or so. MRMS/radar-derived rainfall rates of 1.5-3 inches/hr have already been observed with the deepening convection over the past hour or so. Once deeper convection reaches the coast, it'll encounter areas of wet soils from light to moderate rainfall over the past 6-12 hours or so. FFG thresholds have lowered into the 2.5-4 inch/hr range across the discussion area due to prior rainfall, suggesting that any flash flood threat will be tied to persistent/banded convection that can result in higher rainfall rates. Any urbanized and/or low-lying areas are also of concern as the storms approach from the south. The overall risk is expected to be isolated, but also tied to convective coverage and the degree of banding/persistence. The flash flood risk will increase in areas of Mobile, Alabama metro beginning around 09Z. Cook ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6Klx4jBkO72mzaTPuBW4Va16jNtxdScdNabASY9f-T0-jLCXNZDwCYOPrYqvXDoYb-ux= h-WWgqxlE6al6jJoqjECY5E$ for graphic product... ATTN...WFO...LIX...MOB...TAE... ATTN...RFC...LMRFC...SERFC...NWC... LAT...LON 31578797 31388675 30918586 30528549 30138535=20 29898535 29948566 30048655 29978750 30158839=20 30538899 31328873=20 =3D =3D =3D To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .