Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Jun 09 2025 09:21:32 AWUS01 KWNH 090920 FFGMPD ALZ000-MSZ000-LAZ000-ARZ000-091500- Mesoscale Precipitation Discussion 0409 NWS Weather Prediction Center College Park MD 519 AM EDT Mon Jun 09 2025 Areas affected...Central MS...Southwest AL... Concerning...Heavy rainfall...Flash flooding possible Valid 090920Z - 091500Z SUMMARY...Training WAA convective cells with capability of 2"/hr rates and spots of 2-3"+ may result in possible localized incident(s) of flash flooding through early morning. DISCUSSION...Regional RADAR and surface observations show rapidly decaying MCS continuing to press eastward along the LA/AR border with outflow boundary starting to reach northeast LA where it intersects with slowly lifting frontal boundary that has had some active convection along it earlier this mornign across S MS.=20 Surface to boundary layer winds are increasing with approach of the MCS and slightly increased WAA over the boundary breaking out more numerous updrafts across central MS connecting up to the lifting older cluster out of south-central MS. From 850-500mb, winds are fairly flat from west to east to allow for solid potential for training of these cells. CIRA LPW also denotes the weak amplifcation of the surface to 850mb moisture up the MS River Valley but also still pooled along the deeper layer boundary toward SW AL and active cluster in south-central AL as well. TDs in the mid-70s with 850-500mb moisture axis continue to support 2-2.25" total PWats and with upstream faster flow associated with the MCS, propagation vectors have reduced to about 5kts and are supportive of backbuilding into the approaching outflow boundary.=20 As such a few hours of efficient rainfall/training should allow for 2-3"+ totals across central MS. Slowly the cells will move into more senstive soil conditions from east-central MS into south-west AL from last evening's heavy rainfall, this may increase the potential for higher than normal run-off and incidents of flash flooding, but the air is drier aloft and more stable, and without very strong WAA to advect northward it may be more difficult to maintain stronger convection across this region, but at the same time, will not require as much rainfall totals (2-2.5" in 3-6hrs) than over the drier conditions of central MS. Either way, hourly rates and 3hour totals will be close enough to suggest localized incidents of flash flooding will be possible through early morning hours. Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!49iAVeDqXzTLS09rM5rKAjVr573UgnYL74fGpAMblDT-x7fm-Iwr6ZcscrmThd3BdZSp= ySCU5-yh4-MIx4zdPyLsJR0$ for graphic product... ATTN...WFO...BMX...JAN...MOB... ATTN...RFC...ALR...ORN...NWC... LAT...LON 33649014 33468862 32828762 32548709 32258628=20 31638628 31168664 31268799 31788932 32029021=20 32289124 32859149 33449128=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) .