Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon May 12 2025 02:23:18 AWUS01 KWNH 120221 FFGMPD SCZ000-FLZ000-GAZ000-120820- Mesoscale Precipitation Discussion 0257 NWS Weather Prediction Center College Park MD 1020 PM EDT Sun May 11 2025 Areas affected...Central and Southeast GA...SC Midlands and Lowcountry Concerning...Heavy rainfall...Flash flooding possible Valid 120220Z - 120820Z SUMMARY...Additional rounds of heavy showers and thunderstorms overnight will continue to promote concerns for scattered areas of flash flooding heading into the overnight hours. DISCUSSION...The latest radar and satellite imagery is showing new rounds of heavy showers and thunderstorms lifting up across northern FL and stretching up across areas central to southeast GA and into far southern SC. This again is being supported by a deep layer southerly conveyor belt of warm and moist air lifting into the Southeast U.S. while interacting with a quasi-stationary frontal zone draped across far southern GA and up across coastal areas of SC. The deep layer moisture transport remains well-defined around the eastern flank of a deep layer trough/closed low over the lower MS Valley/western Gulf Coast region and continues to have tropical origins with moisture seen in CIRA-ALPW advancing north up from Central America and the western Caribbean Sea across the eastern Gulf Coast/FL Peninsula and into the Southeast U.S. coastal plain. 00Z RAOB data shows PWs generally near or a little above 1.75 inches which is 2 to 2.5 standard deviations above normal. This moisture transport and warm air advection will continue to support strong isentropic ascent across eastern GA and the SC Lowcountry going into the overnight hours which coupled with the frontal convergence and pooling of instability along it will favor additional concentrated areas of convection with heavy rainfall rates. MLCAPE values across coastal areas of GA and the SC Lowcountry are on the order of 1000+ J/kg and are being aided by cyclonic low-level flow off the warmer waters of the nearby Gulf Stream. Favorable shear parameters are in place too, and thus the environment will be conducive for some organized convective cells with high rainfall rates capable of reaching 1.5 to 2.5 inches/hour. The recent runs of the HRRR/RRFS guidance and also the 18Z HREF/12Z REFS ensemble solutions support the potential for additional rainfall totals reaching 3 to 5 inches. This will support a continued threat for scattered areas of flash flooding heading into the overnight hours. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8WF7wnE_Vld1EJtp-iCOc0LihFjsIFoY6V_v5duHBRtQTw_psBDB8h2ni18qM8AzdxFg= 052o9i4SQ4SmUHBvMcGbRzA$ for graphic product... ATTN...WFO...CAE...CHS...FFC...ILM...JAX...TAE... ATTN...RFC...SERFC...NWC... LAT...LON 34348071 33827990 32817999 32108053 31468104=20 30578150 30468233 30788297 31638315 33048272=20 34058190=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) .