Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Jul 11 2025 04:31:59 AWUS01 KWNH 110431 FFGMPD IAZ000-NEZ000-SDZ000-110930- Mesoscale Precipitation Discussion 0643 NWS Weather Prediction Center College Park MD 1231 AM EDT Fri Jul 11 2025 Areas affected...Eastern NEB...Western & Central Iowa...Far Northeast SD... Concerning...Heavy rainfall...Flash flooding likely Valid 110430Z - 110930Z SUMMARY...Slow moving thunderstorms near mid-level low, with faster moving cluster crossing central IA. Additional 2-4" totals with repeating cells likely to continue localized incidents of flash flooding. DISCUSSION...Complex mid-level evolution continues to provide a favorable environment for strong thunderstorms with high rainfall efficiency; some locations where convection will be more progressive but stronger, while others may be weaker, but slower but both capable of 2-4" add'l totals, likely resulting in scattered incidents of flash flooding. GOES-E WV suite shows stronger main wave over southeast SDak, while a jet max is streaking out of central Rockies supporting an upstream shortwave crossing southern NEB. Binary interaction between the systems is leading to the main wave sharpening and stalling with strong LLJ response with 35-40kts of 850mb flow crossing out of the Central Plains, intersecting with a stationary front that extends from the central NEB/KS boarder north to a low along the Missouri River in far SW IA before extending nearly due east across southern IA. Remaining area of highly unstable air exists at this intersection across SE NEB into southwest/central IA with 3000-3500 J/kg of CAPE and strong moisture flux bringing surface Tds into the low 70s and overall total PWats to 2-2.2" values. Strong, fairly orthogonal isentropic ascent will continue to support stronger convection near the low and eastward.=20 Clusters will have 2.5"/hr rates, but deep layer steering flow parallel to the boundary should be quick to limit overall totals with the initial burst to 1.5-2" though continued upstream convergence should support back-building and training across southwest to central IA. Totals of 2-4" are likely to induce incidents of flash flooding through to 09z. NE NEB/NW IA/SE SDAK... With the deep layer wave stationary, but deepening, the LLJ is responding by backing back from southerly to southeasterly along an inverted surface to mid-level trof/TROWAL-like feature along the Missouri River. As the undercutting jet streak and associated vort max moves across S NEB, convection near the main center will have reduced forward speeds and evolve with similar note to a SHaRS (Subtle Heavy Rainfall Signature), where cores of cells are very slow moving, but produce moderate rainfall in weaker 1000-1500 J/kg of MUCAPE; but in exhausting that well have a few hours to increases those localized totals to 2-4" totals. Some weak cell motion further southeast along the trof/TROWAL may support some repeating as well, but overall more chaotic cell motions are also likely to induce localize incidents of flash flooding especially given lower FFG values (1-1.5"/hr & 1.5-2"/3hr across the Missouri River Valley).=20 Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9vMQT2V05cNdM-4MctxovtSvRzOAZI-yXiFmAqbpXgzSNgnyZEIhKvXV19K9yLcY7Asz= 6hEvdUNd90t-0sMLmwV7coY$ for graphic product... ATTN...WFO...DMX...FSD...OAX... ATTN...RFC...KRF...MSR...NWC... LAT...LON 43429810 43249704 42549493 41919312 41709258=20 41269250 40929265 40949417 40999511 41179664=20 42249754 42879825 43289847=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) .