Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat May 03 2025 07:36:12 AWUS01 KWNH 030736 FFGMPD FLZ000-ALZ000-031300- Mesoscale Precipitation Discussion 0214 NWS Weather Prediction Center College Park MD 335 AM EDT Sat May 03 2025 Areas affected...Coastal Alabama...Western Panhandle of Florida... Concerning...Heavy rainfall...Flash flooding possible Valid 030735Z - 031300Z SUMMARY...Slow moving/stationary coastal thunderstorms to be swept up from west to east through early morning with main pre-frontal convective line. Highly localized 2-4" totals are possible in proximity to urban centers posing possible rapid inundation flooding. DISCUSSION...Regional RADAR mosaic depicts a mature convective line with a few bowing segments continuing to march southeastward across southwest AL into far southeast LA with strong meso-high/cold pool helping its advancement. A weak surface wave appears to have formed in proximity to southern MS, which seems plausible given strength of onshore southerly to southwesterly flow. Strong frictional convergence at the coast at the nose of an enhanced but narrow moisture plume from the mouth of the MS river turning more southwest to northeast toward the AL/W FL coastline continues to feed an expanding (eastward) convective line at the coast. Surface to 700mb moisture per CIRA LPW show values of 1.5 to 1.7" being fed by 15-25kts of flow. Warm Gulf air in the upper 70s to low 80s and modest steepening lapse rates support solid 1500-2000 J/kg of MLCAPE to maintain the stronger updrafts. The combination supports cells capable of 1.5-2"/hr along the warm advective/frictionally forced cells. While pre-frontal convective line is advancing sweeping up/merging along the way, this should result in 2-3 hours of solid rainfall prior to the main line sweeping through. As such, localized totals of 3-4" are possible.=20=20 There is a potential factor that may limit flooding impact that would be related to strength of cold pools from initial convection pressing outflow boundaries off-shore resulting in best convergence and downdrafts to be also offshore. Current trends suggest this is occurring more upstream and nearer the mixing of the EML downward with the main-line convection. So while the soils are very sandy and likely to support solid infiltration, the vast urban locations along I-10 from Mobile to Panama City will have large impermeable surfaces even up to the shoreline; and as such rapid inundation flooding may be possible over the next 4-6hrs as the main line sweeps through. Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-g3JI-d4aOcymSOaieVA6ljwjuWfKKzRO67QyiKkQC3TvB13PzyEWFyW698RGPQffEOd= hJB_C7K0DcwjEW_l83dHHJk$ for graphic product... ATTN...WFO...MOB...TAE... ATTN...RFC...LMRFC...SERFC...NWC... LAT...LON 31008721 30998635 30908573 30268593 30328644=20 30298699 30218751 30248828 30878832 30998805=20 =20=20=20=20=20=20=20=20=20=20=20=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 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .