Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Jun 16 2025 18:40:02 AWUS01 KWNH 161838 FFGMPD TNZ000-KYZ000-INZ000-ILZ000-MOZ000-ARZ000-162330- Mesoscale Precipitation Discussion 0459...Corrected NWS Weather Prediction Center College Park MD 237 PM EDT Mon Jun 16 2025 Corrected for FF Likely Areas affected...Western & Central KY...Southern IND...Southern IL...Southeast MO...Northeast AR...Adj. TN Concerning...Heavy rainfall...Flash flooding likely Valid 161800Z - 162330Z SUMMARY...Slow moving, efficient thunderstorms capable of 2-3" in 1-2 hours pose localized flash flooding conditions, especially upstream over saturated ground conditions/low FFG. DISCUSSION...GOES-E WV suite shows a broad anticyclonic arch of high cirrus indicative of broad mid to upper level confluent flow to speed max over central Ohio Valley (generally 50kts). This results in a broad entrance region with favorable upper-level divergence to support/maintain an elongated shear axis from a stalled/shortwave feature across the eastern Ozark Plateau to a convectively reinforced short-wave crossing southern IL into southwest IND at this time. The combination of broad scale ascent has provided ample broken to dense mid to upper-level cloud features reinforcing surface front through differential heating across northeast AR into Western KY. Visible imagery also helps to denote the surface to 850mb low across N AR with front generally along the southern portion of the cloud line across SE MO, S IL into SW IND. Low level moisture remains above normal and into the low to mid 70s wrt dewpoint and CIRA LPW in the surface to 850mb within the Mississippi and Lower Ohio Valley nearing 1" in places. As such, a plume of 2"+ TPW exists across the area expanding eastward into western KY. Heating into the mid to upper 80s will steadily increase instability over 1500 J/kg MLCAPE with SBCAPEs already over 3000 J/kg. As such, recent convective initiation has been quick and vigorous across S IL/W KY and will likely become quickly efficient in rainfall production given the flux through the core of the moisture plume. Rates of 2"/hr are likey though 15z HRRR hints that 15-minute totals may reach 1.5" given the overall efficiency/deep warm cloud processes. Deep layer flow should allow for cells to be fairly progressive especially east of the MS River valley and organized structures are likely to be clustered along and south of the frontal zone.=20 Random upstream redevelopment has potential for repeating tracks, so spots of 2-3" totals are probable through the late afternoon/early evening. Cells near the surface to 850mb low are likely to be slower in eastward cell motions being a tad further west of the jet entrance with perhaps a cell getting lodged on some of the hills of the eastern Plateau given some favorable upslope. Additionally, FFG values are reduced upstream due to heavy rainfall last evening with 1hr values less than 1.5"...though downstream in W KY are still between 1.5-2" with 3hr values in the 2-2.5" range. While the incidents of flash flooding are likely to be scattered in nature throughout the MPD area, the probability of FFG exceedance is likely and most probable upstream with lower FFG and slower cell motions (though lesser deep moisture/instability). Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7l9PaXvJ-3mUClkVUOSDT5VIoG1TEjQ4JkP9VHyw7iyv5K8FFQuQFnafxN2yO8XvPMVm= 9oJf6Ev-Da7gHQ1Rs_nXBlY$ for graphic product... ATTN...WFO...ILX...IND...LMK...LSX...LZK...MEG...OHX...PAH... SGF... ATTN...RFC...MSR...ORN...TIR...TUA...NWC... LAT...LON 39008653 38658541 38158488 37568483 36788544=20 36538799 35749027 35339189 35679272 36239272=20 37009205 37639098 38588915 38908806=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) .