Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon May 08 2023 07:57:42 AWUS01 KWNH 080757 FFGMPD INZ000-ILZ000-MOZ000-IAZ000-081330- Mesoscale Precipitation Discussion 0237 NWS Weather Prediction Center College Park MD 356 AM EDT Mon May 08 2023 Areas affected...Far Southeastern IA...South-Central IL...Northeastern MO Concerning...Heavy rainfall...Flash flooding likely Valid 080750Z - 081330Z Summary...Rainfall rates as high as 1-2"/hr will provide additional localized totals of up to 2-3". Further isolated instances of flash flooding are considered likely. Discussion...A maturing mesoscale convective system (MCS) is likely to continue to produce a localized flash flood threat over the next several hours, as rainfall rates of 1-2"/hr overspread areas that have 1-3"+ over the past 6 hours. The mesoscale environment is characterized by MU CAPE of 500-2500 J/kg, precipitable water values of 1.0-1.4 inches (near the 90th percentile, per DVN and ILX sounding climatology), and effective bulk shear of 40-50 kts. A shortwave trough will continue to provide necessary lift to the maturing system, while Corfidi downshear vectors are likely to maintain a rather progressive storm motion of 40-60 kts toward the east to east-southeast. While this rapid progression should limit the overall extent of any flash flood impacts, localized/isolated flash flood impacts are still considered likely (especially given the 1-3"+ amounts that have been realized recently, increasing overall hydrologic sensitivity). The chances for more scattered to widespread impacts are considered unlikely, given the developed cold pool and associated forcing that should overcome the effects of the 850-300 mb mean wind downstream (which is as low as 15-20 kts across central IL). In addition, the low-level jet (LLJ) is expected to weaken from 20-30 kts to 10-20 kts over the next 4 hours, while also veering towards the west and limiting additional favorable moisture transport. Areas most likely to experience additional flash flooding extend from central IL southeastward into south-central IL (generally from just south of Burlington, IA to just south of Springfield, IL). Churchill ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5jJSYVLMojtw_VK9tj78DeR-BBO4KTW3IMDILpXhLvwRWpz4Qrt2CqVpevWi4dlJbGQ_= oO2U9CB6pZG9YX9KVpdA1jo$ for graphic product... ATTN...WFO...DVN...EAX...ILX...IND...LOT...LSX...PAH... ATTN...RFC...LMRFC...MBRFC...NCRFC...OHRFC...NWC... LAT...LON 41759003 40238786 38898759 37608854 38209121=20 39219266 41129157=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) .