Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Jul 01 2023 23:25:37 AWUS01 KWNH 012325 FFGMPD INZ000-ILZ000-020430- Mesoscale Precipitation Discussion 0617 NWS Weather Prediction Center College Park MD 724 PM EDT Sat Jul 01 2023 Areas affected...Central Illinois to Central Indiana... Concerning...Heavy rainfall...Flash flooding possible Valid 012330Z - 020430Z SUMMARY...Increasing convective development within deformation zone. Slowing cell motions may result in spotty 2-3" storm totals across wet soil conditions. Increased runoff may result in a few scattered incidents of flash flooding through early overnight period. DISCUSSION...GOES-E WV suite depicts a mature convective system as associated southern stream shortwave trof crossing the Mississippi River into southwest IL along the interface of downstream deformation trough from the synoptic northern stream through the southern Great Lakes. Regional RADAR mosaic depicts a band of stronger thunderstorms along the northern leading edge of the complex, along with elevated cells in proximity to the deformation zone in central IL. A ribbon of modest but still unstable air generally about 1500-2000 J/kg exists within this region. As the western portion of the southwesterly low level flow converges, there should be ample ascent to allow for either newer cell development or maintaining cells along the leading edge. However, in the convergence, deeper layer steering flow will slacken allowing for cell motions to slow, increasing duration. Very high total PWat values (2-2.25") are being advected to support highly anomalous moisture flux convergence values to support high rainfall efficiency. Scattered intense cores will support very intense short-term rates with 18z HRRR suggesting 15-minute totals in the 1.2-1.5" range, that should diminish fairly rapidly from west to east exhausting the local instability. Localized 1-2 hour lingering rainfall should allow for scattered shot pattern of 2-3" totals along the axis.=20 Hydrologically, much of this area has seen heavy rainfall over the past few days, with AHPS 7day anomalies of 200-300% from Springfield to Terra Haute and in the vicinity of Peoria and eastward toward Lafayette, IND. As such, FFG values are both lower in the axis and generally at or below 1.5"/hr and less than 2.5/3hrs. As such, scattered localized incidents of flash flooding remain possible through the early overnight period. Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7Gbf2Y6Xa_EiBj_Ri04jUBFHrSJELbe3OPUpoo8bp5q_JtDIfBVE6koOYa4kkybK-d3P= puv3J8cVT8PrMbGXhuKh_xU$ for graphic product... ATTN...WFO...ILX...IND...IWX...LOT... ATTN...RFC...NCRFC...OHRFC...NWC... LAT...LON 41038795 40828632 40358529 39448556 39048660=20 39418817 39699016 40959005=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) .