Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun May 11 2025 20:58:24 AWUS01 KWNH 112057 FFGMPD SCZ000-GAZ000-120255- Mesoscale Precipitation Discussion 0255 NWS Weather Prediction Center College Park MD 456 PM EDT Sun May 11 2025 Areas affected...Portions of Central and Eastern GA...SC Midlands and Lowcountry Concerning...Heavy rainfall...Flash flooding likely Valid 112055Z - 120255Z SUMMARY...Scattered areas of flash flooding will be likely going through the early to mid-evening hours from locally slow-moving and training showers and thunderstorms. DISCUSSION...The latest radar and satellite imagery shows an expansive area of heavy showers and thunderstorms impacting areas of central/eastern GA and through western/central SC as a deep layer southerly conveyor belt of warm and moist air lifts into the Southeast U.S. and interacts with a stationary front draped west to east across southern GA and the SC Lowcountry. The deep layer moisture transport is well-defined around the eastern flank of a deep layer trough/closed low over the lower MS Valley/western Gulf Coast region and has tropical origins with moisture seen in CIRA-ALPW advancing north up from Central America and the western Caribbean Sea across the eastern Gulf Coast region and into the Southeast U.S. PW values are 1.75+ inches which are a solid 2 to 2.5 standard deviations above normal, and the latest 850/700 mb moisture flux anomalies are as much as 2 to 4 standard deviations above normal. This moisture transport and warm air advection will continue to support strong isentropic ascent across central and eastern GA and the SC Lowcountry through this evening which combined with moderate instability near the aforementioned front will support areas of organized convection with heavy rainfall rates. MLCAPE values across areas of southeast GA are still on the order of 1500 J/kg with a strongly convergent low-level flow pattern in place given proximity of the front. However, the recent convective activity has resulted in some lowering of CAPE values over the last few hours. Nevertheless, expect sufficient levels of forcing and instability to continue going into the evening hours for additional rounds of heavy showers and thunderstorms which will be capable of producing rainfall rates of up to 1.5 to 2.5 inches/hour with the stronger convective cores, and especially with the efficient/moist deep layer tropical origins of the moisture transport. Areas of far eastern GA and possibly getting into areas of the SC Lowcountry will need to be closely monitored this evening for areas of notable cell-training as the convection here should be stronger and more focused with alignment also with the deeper layer steering flow. A wave of low pressure traversing the stationary front will be a key player in driving this threat. Some additional rainfall totals may reach 3 to 5+ inches (supported be HRRR and RRFS solutions), and given the rainfall that has already occurred, there will likely be scattered areas of flash flooding. This will include an urban flash flood threat, with even major metropolitan areas well to the north including Atlanta, GA and Columbia, SC potentially seeing some urban flooding concerns from heavy rainfall. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-PQNebJgmP1ejftQdPTKYsNq38Pe_C5zhc11_orRsASTcEKKmm_MlpI0cl_96R4J4cha= O7Ln1hUrQxIGMPBkSrABizo$ for graphic product... ATTN...WFO...CAE...CHS...FFC...GSP...JAX... ATTN...RFC...SERFC...NWC... LAT...LON 34338150 34078036 32928007 32298059 31808105=20 31278122 31168179 32068257 32358384 33058499=20 33688492 33888415 33718258=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) .