Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Apr 02 2024 19:43:55 AWUS01 KWNH 021943 FFGMPD PAZ000-WVZ000-OHZ000-KYZ000-INZ000-030140- Mesoscale Precipitation Discussion 0130 NWS Weather Prediction Center College Park MD 342 PM EDT Tue Apr 02 2024 Areas affected...Much of the Upper OH Valley Concerning...Heavy rainfall...Flash flooding possible Valid 021940Z - 030140Z SUMMARY...Increasing coverage of showers and thunderstorm activity going through the afternoon and evening hours will set the stage for renewed concerns for flash flooding. DISCUSSION...In the wake of morning convection, and with diurnal heating resuming across large areas of southern IN and through much of central/southern OH, the airmass across the region will be destabilizing rather quickly over the next couple of hours. This will set the stage for new areas of heavy showers and thunderstorms, which inclusive of severe weather concerns, will also be capable of producing sufficient levels of additional rainfall for a renewed flash flooding threat. A strong upper-level trough and associated area of surface low pressure will be traversing the OH Valley and portions of the Great Lakes region through the afternoon and evening hours, and this will drive a cold front steadily off to the east. MLCAPE values on the order of 1000+ J/kg are nosing northeast up across southern IN currently just ahead of the cold front, and this coupled with strong vertical shear and pockets of locally focused surface moisture convergence aided by a southwest low-level jet of 40 to 50 kts will favor an increase in the coverage of heavy showers and thunderstorms over the next few hours. This will especially be the case as the downstream boundary layer along and south of a west/east oriented warm front continues to destabilize. The more organized pockets of convection, which should gradually include some supercells and linear convective segments, will be capable of producing rainfall rates that reach 1.5" to 2"/hour. The relative moist environment with PWs approaching 1.25 inches and the strong and sustainable updrafts within the stronger cells will be key contributors to the locally enhanced rates. Some localized training of these convective cells will be possible as the activity gradually expands in coverage, and this may produce some linear swaths of 2 to 4 inches of rain where this occurs. Given the heavier rains earlier in the day and last night, many areas across the broader Upper OH Valley are rather sensitive to any additional heavy rainfall. Therefore, additional concerns for flash flooding will exist heading into the evening hours. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6Vv6teLVsDjKwM2iQ-ykrBPHmnettCaN__iKSov7maXjSfpLm3YuIHI4pnNu1giXlbnj= ZhtAa9PlsbjYa6QY5E3nFU0$ for graphic product... ATTN...WFO...CLE...ILN...IND...IWX...LMK...PAH...PBZ...RLX... ATTN...RFC...OHRFC...NWC... LAT...LON 41408056 41117933 40317917 39747951 39458021=20 39158163 38998330 38528519 37688714 37998776=20 39148693 39948580 40658442 41208242=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) .