Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Jul 29 2023 04:38:24 AWUS01 KWNH 290438 FFGMPD OHZ000-MIZ000-INZ000-WIZ000-ILZ000-IAZ000-290857- Mesoscale Precipitation Discussion 0806...Corrected NWS Weather Prediction Center College Park MD 1237 AM EDT Sat Jul 29 2023 Corrected for Flash flood 'likely' tag Areas affected...northern/central Illinois, northern/central Indiana, far southern Wisconsin, far eastern Iowa, far southwestern Lower Michigan, far western Ohio Concerning...Heavy rainfall...Flash flooding likely Valid 290257Z - 290857Z Summary...Scattered to numerous thunderstorms will continue to pose a flash flood risk across the discussion area through 09Z. Discussion...Scattered to numerous thunderstorms have materialized across the discussion area within a couple of regimes: 1) with forward-propagating convection across northwestern Illinois and southern Wisconsin and 2) along a synoptic front extending from northern Illinois eastward across northern Indiana (generally from RFD to FWA). The storms across southern Wisconsin/northwestern Illinois have well established cold pools/bow echoes and areas of rain rates as high as 1-1.5 inches per hour - locally higher where cell mergers were observed. Meanwhile, storms from northern Illinois into northern Indiana have shown more of a tendency to backbuild along the front while ingesting very moist/unstable air (2000+ J/kg MLCAPE and 1.8+ inch PW values). Additionally, the storms along the front were focused along an axis of appreciable 850mb convergence that remained nearly stationary, allowing for very efficient rainfall processes and slow movement. Spots of 1-2.5 inch/hr rain rates were prompting MRMS Flash responses - especially across northern Illinois. The overall regime will promote several cell mergers and areas of prolonged heavy rainfall as upstream linear MCSs migrate east-southeastward along the front. Areas of 3-5 inches of total rainfall are expected - with highest totals along the aforementioned front generally from RFD to FWA. These areas are also the most likely to experience multiple rounds of precipitation associated with cells along the front and upstream MCSs.=20 Over time, CAMs and observations suggest that enough of a southward component of motion will exist to enable somewhat faster storm motions (due to continued upscale growth and forward propagation) which should gradually lessen the flash flood risk through the night. This process will take a few hours to unfold, however. Cook ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6mvfJ4KyCaaWvua2ZZAQgKpWh2IQQ-aJ5Fiofz7du8RDasJBglxrw2zPn1fy2bAA273b= ryzpaXD_3SVAZMDODQqaIQg$ for graphic product... ATTN...WFO...ARX...CLE...DVN...GRR...ILN...ILX...IND...IWX... LOT...MKX... ATTN...RFC...NCRFC...OHRFC...NWC... LAT...LON 43718928 42798608 40898371 39508364 39288562=20 39898936 41559139 43369000=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) .