Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Jun 12 2023 04:25:40 AWUS01 KWNH 120425 FFGMPD NCZ000-SCZ000-GAZ000-TNZ000-120800- Mesoscale Precipitation Discussion 0467 NWS Weather Prediction Center College Park MD 1224 AM EDT Mon Jun 12 2023 Areas affected...Far Western NC/SC...Northern GA Concerning...Heavy rainfall...Flash flooding possible Valid 120420Z - 120800Z Summary...Heavy rainfall may lead to additional localized 2-3" over the next several hours. Isolated instances of flash flooding are possible. Discussion...A shortwave trough continues to drive convective activity across portions of the Southeast at this hour, and possible isolated instances of flash flooding are becoming a concern across northern GA and surrounding portions of the Carolinas. An estimated 1-2" of rain has already fallen across localities in far northeastern GA and western SC (per MRMS), and an approaching squall line from the west only looks to add to those totals over the next several hours. The mesoscale enviornment along and ahead of the squall line is characterized by SB CAPE of 500-1500 J/kg, PWATs of 1.5-1.7 inches (near the 90th percentile, per FFC sounding climatology), and effective bulk shear of 25-35 kts. This parameter space should continue to support organized convection and heavy rainfall (especially given ongoing strong low-level moisture transport from the southwest), with additional hourly accumulations of 1-2" likely across a good portion of the area. While most locations can probably handle this amount of additional rainfall, it could become problematic in spots given that 1-2" of rainfall occured earlier in the day across much of northeast GA and western SC (not including the swath of most recent 1-2", which adds up to as much as 2-4" locally near the western tip of SC). The 00z HREF neighborhood exeedance probabilities helped to inform the MPD area, with a bullseye of 40-50% probabilities for 2" exceedance near the western tip of SC (falling to 20-40% odds for much of the surroundings). The HREF EAS neighborhood probabilities for greater than an inch were also notable, as high as 20-30% for the western tip of SC (and 10-15% across the surrounding and much of northern GA). The HRRR runs since 21z have shown depictions of QPF locally as high as 2-4" (always in the vicinity of the western tip of SC), with localized totals of 1.5-2.0" much more common. Considering all of the CAM guidance, isolated instances of flash flooding are considered possible (and most likely in the vicinity of the western tip of SC). Churchill ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7SAokKJm6-jX7XHTOeu_iXmzZG9D3vV8naqPkuWOUNhKn149n8CeCQpwUmjcvuIkChHq= Ovwoa9TSWltbJNK6BWwcGPI$ for graphic product... ATTN...WFO...CAE...FFC...GSP...MRX... ATTN...RFC...LMRFC...SERFC...NWC... LAT...LON 35368295 35318243 35048183 34568189 33998230=20 33538350 33458454 33678499 34068524 34548526=20 34878499 35008473 35218407 35318351=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) .