Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Jul 11 2025 22:22:10 AWUS01 KWNH 112221 FFGMPD WIZ000-ILZ000-MOZ000-IAZ000-KSZ000-120419- Mesoscale Precipitation Discussion 0650 NWS Weather Prediction Center College Park MD 620 PM EDT Fri Jul 11 2025 Areas affected...portions of the Upper Midwest Concerning...Heavy rainfall...Flash flooding likely Valid 112219Z - 120419Z Summary...An incoming convective line with preceding thunderstorms is expected to lead to cell mergers in the near term. Hourly rain amounts to 2.5" and local totals to 4" remain likely through 02z, and possible thereafter. Scattered to numerous areas of flash flooding are anticipated. Discussion...An MCV appears to be forming across northeast IA in association with a broadening and maturing convective complex over the Upper Midwest. Precipitable water values are near 2". ML CAPE up to 3500 J/kg lies within the warm sector. Effective bulk shear of 30-45 kts is helping to organize the convective area. In the near term, cell mergers between the incoming line and preceding convection along with random mesocyclones are expected to lead to hourly rain amounts to 2.5" with local amounts to 4" until at least 02z. Thereafter, a narrowing convective footprint is expected as it reduces the instability pool currently in the warm sector and the convective line winnows and picks up the pace. Still, random mesocyclones along the line after 02z could lead to a LWEP or QLCS structure for at least a couple more hours which would lead to locally heavy rainfall. Some portions of the region -- particularly northern IL & portions of Chicago -- have seen heavy rainfall recently, which has led to low flash flood guidance. Scattered to numerous flash flood events are expected through 02z, even outside urban areas, before becoming more scattered to widely scattered thereafter. Roth ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7Pgb-1FuaLDx04VaBZ-oBegYbYeEWKkWJYrgr88yWUqV8asucDTVdmYB1Bx8MdEMF6It= xmZ7l2X_4IHxq_uda6li5_w$ for graphic product... ATTN...WFO...ARX...DMX...DVN...EAX...ILX...LOT...LSX...MKX... ATTN...RFC...KRF...MSR...NWC... LAT...LON 43269062 43258926 42508784 41798763 40988958=20 40029112 39239240 39059416 39729497 41109433=20 41709295 42099149 42739114=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) .