Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Aug 07 2023 16:31:37 AWUS01 KWNH 071631 FFGMPD PAZ000-MDZ000-WVZ000-OHZ000-KYZ000-072200- Mesoscale Precipitation Discussion 0881 NWS Weather Prediction Center College Park MD 1229 PM EDT Mon Aug 07 2023 Areas affected...Portions of the Upper OH Valley and the Central Appalachians Concerning...Heavy rainfall...Flash flooding possible Valid 071628Z - 072200Z SUMMARY...Strong to severe thunderstorms crossing portions of the Upper OH Valley and the central Appalachians over the next several hours may also produce at least a localized threat for some flash flooding. DISCUSSION...The latest GOES-E satellite imagery shows convection well underway across areas of the Upper OH Valley as a strong upper-level trough advances east and encounters and increasingly moist and unstable airmass as robust diurnal heating ensues. Already there is a nose of MLCAPE values reaching 1500 to 2000+ J/kg across areas of northern KY through southern OH and into western WV, and PWs are locally as high as 1.75 inches which is as much as 1.5+ standard deviations above normal. Enhanced thermodynamics coupled with a strongly sheared vertical column with effective bulk shear of as much as 40 to 50 kts will be leading the way for well-organized bands of convection including some supercells over the next few hours as convection grows upscale and advances progressively off to the east into the the central Appalachians. A well-defined severe weather component will accompany this convective evolution going through the afternoon hours, however, there may be just enough of a cell-training component to the activity to promote at least a localized threat for some flash flooding. Given the environment, rainfall amounts of as much as 1 to 2 inches will be possible in as little as 30 minutes to an hour. With at least some episodic instances of cell-training, some localized storm total amounts of 2 to 4 inches will be possible. The 12Z HREF guidance favors portions of far southern OH through western and central WV for seeing the greatest threat of this, and this is where there are relatively high 3-hour FFG exceedance probabilities noted. As mentioned, the dominant hazards will be with the severe weather threat (please consult SPC MDs and watch information for more details), but expect at least locally there to be enough rainfall for some overlapping flash flood threat given the high rainfall rate potential with the convection. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!80Ll9LWyPFZxeJMLRi45Sv2vrOd1NLxnSywdTzIrjripal7xcq2eYcK7-yES_rF-VOcd= Itfbl8TraPO0JZzzbdskf8k$ for graphic product... ATTN...WFO...CTP...ILN...JKL...LMK...LWX...PBZ...RLX... ATTN...RFC...MARFC...OHRFC...NWC... LAT...LON 40177972 39767894 39167912 38787981 38398123=20 38138310 38298437 38898427 39598324 40098143=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 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .