Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Jul 01 2025 00:50:19 AWUS01 KWNH 010049 FFGMPD TNZ000-KYZ000-INZ000-ILZ000-MOZ000-ARZ000-010630- Mesoscale Precipitation Discussion 0562 NWS Weather Prediction Center College Park MD 849 PM EDT Mon Jun 30 2025 Areas affected...Southeast MO...Southern IL...Southwest IND...Far Western KY... Concerning...Heavy rainfall...Flash flooding possible Valid 010050Z - 010630Z SUMMARY...Slow moving, efficient thunderstorms to increase in coverage with cell mergers, potential repeat tracks resulting in localized 2-4" totals resulting in scattered possible flash flooding tonight. DISCUSSION...GOES-E WV suite shows a southern stream shortwave sliding out of SE MO into S IL south of the digging synoptic northern stream trough across WI to NE KS with an associated cold front. This front continues to dig south across the middle Great Lakes but due to the shortwave, a weak surface wave has developed in the buckling mid-level flow near Quincy, IL; before the cold front digs across central MO. The mid-level binary interaction between the shortwave and northern stream will further slow deep layer flow and help with boundary layer cyclogenesis near/southeast of the St.Louis Metro.=20 Low level winds are already backing and deep layer moisture is increasing across S IL with solid convergence breaking out numerous updrafts. MLCAPEs of 2000+ J/kg and PWats over 2" will allow for strong moisture flux convergence into stronger updrafts and will support rates of of 2-2.25"/hr. These cells should remain along the southeast and eastern quadrants of the shortwave with perhaps a flanking line along the effective cold front/trailing convergence trof back into the Bootheel of MO.=20 Cell motions will continue to be eastward to east-northeastward with some solid potential for mergers/training. Spots of 2-4" will become scattered acoss S IL into SW IND/W KY over the next 4-6hrs with possible localized flash flooding. A bit more uncertainty with respect to flash flooding will occur with ongoing cells along the synoptic cold front. Most should remain progressive, but near the pivot; deeper confluence and chaotic cells motions as the cyclone tries to vertically stack/pivot may allow for some widely scattered cells that could pivot or potentially remain stationary as well. Cells may initially be close to Metro St. Louis to further make evolution of potential flash flooding more concerning, as broader impermeable surfaces would result in greater runoff IF cells do end up lingering in that vicinity further increasing potential for flash flooding. Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!44AqSVeDllzwflwf0drMlrW1BejRylhHjVeRkBfuXLOCpkfj6FnkpP0-rqT5BzrPLrV_= xPvPaqHPxh4o5iUAMZxKWkM$ for graphic product... ATTN...WFO...ILX...IND...LSX...MEG...PAH... ATTN...RFC...KRF...MSR...ORN...TIR...NWC... LAT...LON 39938840 39818771 39178716 38418712 37948730=20 37568743 36628879 36378987 36499049 37299055=20 37889064 38559137 38949136 39299103 39528961=20 =20=20=20=20=20=20=20=20=20=20=20=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) .