Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Aug 02 2024 22:06:16 AWUS01 KWNH 022206 FFGMPD PAZ000-WVZ000-OHZ000-KYZ000-MIZ000-INZ000-030405- Mesoscale Precipitation Discussion 0784 NWS Weather Prediction Center College Park MD 605 PM EDT Fri Aug 02 2024 Areas affected...Portions of the Lower Great Lakes and Upper OH Valley Concerning...Heavy rainfall...Flash flooding possible Valid 022205Z - 030405Z SUMMARY...Scattered to broken areas of heavy showers and thunderstorms will promote a threat for isolated to widely scattered instances of flash flooding going through the evening hours. DISCUSSION...The late-day GOES-E GeoColor satellite imagery in conjunction with dual-pol radar shows scattered to broken areas of showers and thunderstorms impacting areas of southeast MI down through eastern IN and western OH. The activity continues to be influenced by a deep layer low pressure system that is gradually settling east-southeast into the OH Valley. DPVA ahead of the low center and interaction with a moist/unstable airmass across the upper OH Valley region should favor a regional threat of locally heavy showers and thunderstorms going well into the evening hours. MLCAPE values remain on the order of 1500 to 2000 J/kg across much of central and western OH, with somewhat lesser values seen farther off to the east into northern WV and western PA. Meanwhile, PWs across the region are locally around 1.75 inches, and these magnitudes are somewhat anomalous (1.5+ SD above normal) for this time of the year. Rainfall rates with the areas of convection this evening are expected to be as high as 1 to 2 inches/hour. Gradually by later this evening as boundary layer instability becomes increasingly exhausted, the rainfall rates and general coverage of convection should begin to subside. However, going through at least the mid-evening hours, the storms will be sustainable and will also be rather slow-moving. The slow cell-motions and heavier rates will foster a threat for some localized 2 to 4 inch rainfall totals. The 12Z/18Z HREF guidance generally supports this potential and does reflect some low-end probabilities of seeing the 1-hour and 3-hour FFG values exceeded as this evening's convection advances east across the upper OH Valley. This will include much of central and eastern OH, northern WV and far western PA in time. Thus, the expectation is that some isolated to widely scattered instances of flash flooding will be possible. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8jKmFZZ00F8GO9hGhsucdGVrER7Xh5t6ba3AXHLkh2Z9tIERgBdK0EfyGnq8mqPg3ybk= SszxHU21rd5nvV6YQRrPnjE$ for graphic product... ATTN...WFO...CLE...ILN...IND...IWX...JKL...PBZ...RLX... ATTN...RFC...NCRFC...OHRFC...NWC... LAT...LON 41778496 41538338 41438204 41498091 41597995=20 41007940 40137941 39048014 38368179 38428361=20 38978488 39868554 40838581 41508566=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) .