Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Mar 31 2025 02:30:21 AWUS01 KWNH 310230 FFGMPD VAZ000-TNZ000-KYZ000-ALZ000-MSZ000-ARZ000-310800- Mesoscale Precipitation Discussion 0097 NWS Weather Prediction Center College Park MD 1029 PM EDT Sun Mar 30 2025 Areas affected...Central & Eastern KY...Western & Middle TN...Northern MS...Northwest AL... Concerning...Heavy rainfall...Flash flooding possible Valid 310230Z - 310800Z SUMMARY...QLCS starting to have bowing segments that will result in a few streaks of enhanced moisture convergence and increased heavy rainfall duration resulting in streaks of 2-4" totals and possible localized flash flooding. DISCUSSION...Regional RADAR mosaic denotes solid and broadening squall line across central KY angling back across W TN into far northeast AR. Maturing bowing segments are starting to arch out with meso-low/inflections noted in the north near Henry county, N KY and Christian/Tocd counties in S KY and generally flattening near the tail of sufficient deeper layer convergence/mid-level forcing from the exiting shortwave across central IND. Modestly broad wedge axis of unstable air remains in place along/ahead of the line with 500 along the Ohio River back to 2000 J/kg MLCAPE across N MS/W TN attm. Moisture is not particularly deep, through the layer, but the strength of flux on 40kts of confluent boundary layer to 850mb flow has resulted in 1.25-1.5" total PWat values.=20 Given the strength of the convergence both in speed and direction through depth intersecting with outflow boundaries will support solid rates of 1.5-2"/hr with bulk falling in initial 15 minutes (HRRR and WoFS sub-hourly rates suggesting 1.25/15 minutes with ..35-.5"/5 minutes rates, respectively). While the broad post-squall shield precipitation is increasing, especially further north toward better divergence aloft, overall totals are likely to be around that 1.5-2" range, which remains slightly below even 1hr FFG values across KY (which are higher south). However, given these bowing segments and embedded inflections are helping to back sfc to boundary layer flow with oriented outflow boundaries, orthogonal to the flow, isentropic ascent will increase downstream and increase duration in proximity of these inflections, allowing for localized 2-3" streaks to form along the QLCS, as well as the tail end cells where forward steering flow is weaker across W TN/N MS. WoFS 90th percentile have some suggestions of totals nearing 4" across N Middle TN, which seems plausible. Still 3hr totals of 3" would pose possible flash flooding even into the southern portion of the MPD area of concern (though 3+ to 4" would make it more probable). As such, most locations will not see flooding concerns, but there is enough of a signal and trends to suggest a few streaks will result in flash flooding through early morning.=20 Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_Dlp-AeuNUkFkJlNKzpWnEBpHwKhb9-PpUlIRugJipmdYcfc01QVbsKnw8MzjoE4Bx2x= 0ocA-wSkgzmS-6Kn9JWtxOU$ for graphic product... ATTN...WFO...HUN...JKL...LMK...MEG...MRX...OHX...PAH... ATTN...RFC...LMRFC...OHRFC...SERFC...NWC... LAT...LON 38268398 37908305 37108282 36388380 35388543=20 34658724 34338937 34609036 35349034 36128917=20 36708833 37838627 38238537=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) .