Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Jul 20 2025 19:02:49 AWUS01 KWNH 201901 FFGMPD VAZ000-NCZ000-WVZ000-OHZ000-TNZ000-KYZ000-INZ000-210100- Mesoscale Precipitation Discussion 0767 NWS Weather Prediction Center College Park MD 300 PM EDT Sun Jul 20 2025 Areas affected...Far Southeast IN...Southern OH...Central and Southern WV...Eastern KY...Southwest VA...Northeast TN Concerning...Heavy rainfall...Flash flooding likely Valid 201900Z - 210100Z SUMMARY...Scattered to numerous areas of flash flooding will become likely this afternoon and this evening from expanding coverage of thunderstorms with heavy rainfall rates. Some locally significant flash flooding impacts will be possible over areas of sensitive and rugged terrain. DISCUSSION...The mid-afternoon GOES-E visible satellite imagery shows convective initiation taking place across eastern KY through northeast TN and southern WV. However, a more organized band of convection associated with the remnants of upstream shortwave energy over the OH Valley is seen advancing across areas of southern OH with some recent development noted back toward far southeast IN. This more organized cluster of storms will be expanding further in coverage this afternoon given an increasingly unstable and very moist airmass that is pooled across much of the broader OH/TN Valley region and the central Appalachians. MLCAPE values of 1500 to 2500+ J/kg are in place across much of the region, and the airmass is very moist with PWs running locally near the 90th percentile of climatology with values as high as 1.75 to 2 inches. Surface dew points near the OH River and down across much of eastern KY are in the upper 70s to near 80 degrees, and this is another key factor driving elevated CAPE values. There is a belt of stronger mid-level flow traversing the OH Valley in conjunction with the aforementioned shortwave energy arriving from the west, and this is facilitating some rather elevated effective bulk shear values (30 to 45 kts) across southern OH, northern KY and western WV. This kinematic environment coupled with the strong instability will certainly favor the aforementioned band of convection sustaining itself over southern OH, but likely growing upscale over the next several hours as it drops east-southeastward. More terrain-driven convective development is also expected to continue farther south over eastern KY through much of the western slopes of the central Appalachians. Rainfall rates with the stronger storms should easily be able to reach 1.5 to 2.5 inches/hour, and some storm totals by this evening may reach 3 to 4+ inches where some localized cell-training concerns set up. The antecedent conditions are quite moist across most of the region, and these additional rains are likely to promote scattered to numerous areas of flash flooding through this evening. The more sensitive and rugged terrain of eastern KY through central and southern WV may potentially see some concerns for more significant flash flooding impacts given the enhanced runoff threat from these higher and locally persistent rainfall rates. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9P6WgqPdqhkhdZrIfh0D7oQ_Ia09PhrC5l1kXiqQQ2HS7q5KThHAgMkJenITOma-y_PF= EWztvcpMhzYYMPU5bZOJ4zo$ for graphic product... ATTN...WFO...ILN...IND...JKL...LMK...MRX...PBZ...RLX...RNK... ATTN...RFC...ORN...TIR...NWC... LAT...LON 39768246 39648144 39218021 37808049 36358188=20 35978301 36308377 37148439 37938508 38428567=20 38988586 39288534 39558424=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) .