Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Aug 22 2025 22:32:16 AWUS01 KWNH 222232 FFGMPD SCZ000-FLZ000-GAZ000-230430- Mesoscale Precipitation Discussion 0978 NWS Weather Prediction Center College Park MD 630 PM EDT Fri Aug 22 2025 Areas affected...Southern and Eastern GA...SC Lowcountry Concerning...Heavy rainfall...Flash flooding likely Valid 222230Z - 230430Z SUMMARY...Additional areas of very heavy shower and thunderstorm activity going through the evening hours will maintain a likelihood for more areas of flash flooding. DISCUSSION...The late-day GOES-E IR satellite imagery in conjunction with regional radar shows broken areas of very heavy shower and thunderstorm activity continuing to impact areas of the SC Lowcountry on down through eastern and southern GA. A combination of a stationary front along with multiple mesoscale outflow boundary collisions within a very moist and unstable airmass continues to facilitate the ongoing convection, and additional clusters of convection should continue into the evening hours. MLCAPE values are as high as 1500 to 2500 J/kg and this coupled with PWs of 2.2 to 2.4 inches will drive rainfall rates to locally still be well into the 2 to 3 inch/hour range with the stronger storms at least through early this evening. The additional rainfall footprint this evening will be dictated by the longevity of the instability pool along the front, but also mitigated by the proximity of convergent and moist low-level flow near the front, and with some weak right-entrance region upper jet forcing overhead. Recent runs of the experimental WoFS along with the HRRR and RRFS guidance suggest the convection may linger well into the evening hours, with some rather heavy additional totals. The steering flow over the region is also rather weak, and this is supporting slow cell-motions which with the high rainfall rates will favor some additional rainfall totals locally reaching 3 to 5 inches. In fact, the 90th percentile of the 6-hour QPF from the 21Z WoFS run suggests parts of south-central GA may see additional rainfall totals locally exceeding 6+ inches. Given the setup and additional rainfall potential, more areas of flash flooding are likely to occur going into the evening hours. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-98S0FHjnkcohEfm_nUkKVaiZlQrId7Kl_gFVyksAPYyKlrHPOkpHeJVtfjDnAFk0Lus= qEVHPwURi9hindXil4gpUDM$ for graphic product... ATTN...WFO...CAE...CHS...FFC...ILM...JAX...TAE... ATTN...RFC...ALR...NWC... LAT...LON 33668279 33588217 32958109 33387968 32897949=20 32587992 32028077 30918166 30608323 30948457=20 31638505 32268485 32918396=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 3.28-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .