Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Oct 19 2025 03:02:10 AWUS01 KWNH 190302 FFGMPD ALZ000-MSZ000-LAZ000-ARZ000-190800- Mesoscale Precipitation Discussion 1202 NWS Weather Prediction Center College Park MD 1101 PM EDT Sat Oct 18 2025 Areas affected...northern LA/MS border into north-central MS and western AL Concerning...Heavy rainfall...Flash flooding possible Valid 190259Z - 190800Z Summary...Training of heavy rain is expected to result in 1 to 2 inches of rain in an hour and localized totals of 2 to 4 inches through 08Z from the LA/MS border into western AL. These higher rain rates may result in isolated flash flooding. Discussion...Radar mosaic imagery from 0230Z showed a NE to SW axis of thunderstorms extending from western TN into northern and western MS and far northeastern LA, co-located with an elongated outflow boundary. A few linear clusters of thunderstorms were also observed upstream, across southern AR into northwestern LA, located ahead of the base of an upper trough tracking east through OK and northern TX. The environment across the Lower Mississippi Valley was characterized by MLCAPE of 500-1000 J/kg and PWATs between 1.7 and 2.1 inches per 02Z SPC mesoanalysis data and the 00Z sounding from JAN. Southerly to southwesterly 850 mb winds of 30-40 kt were present from LA into MS, allowing low level moisture transport and lift atop rain-cooled air with mean storm motions oriented from the southwest in MS but veering toward the west across northwestern LA. Flow aloft was diffluent, out ahead of the base of the larger scale upper trough located over the central U.S. Given the available instability and source region emanating from the south, continued forcing via synoptic scale and mesoscale processes, some filling in of convection between the leading outflow in MS and trailing activity in northern LA is expected over the next couple of hours. The potential for training is high from the MS River eastward, but the duration of training is questionable. However, even a 30-60 minute window of SW to NE training should be able to produce 1 to 2 inches of rain with potential for 2-4 inches if training is able to set up for a bit longer duration. These rainfall values may result in flash flooding. Dry antecedent conditions should limit flash flood potential, but these locally higher rain rates could focus an isolated threat across urban locations or other locations of poor drainage. The flash flood threat is expected to move east out of the area after 08Z. Otto ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6MfX7yQlfiyfp69R0kFRwFC3E8EHDjXyDpEXrvnWCgZOK-zFQ-gELrRZAMUrmhSEBGtP= 3elaqsqk3bTTxnZoW3dWFAk$ for graphic product... ATTN...WFO...BMX...JAN...MEG...SHV... ATTN...RFC...ALR...ORN...NWC... LAT...LON 34128834 33358769 32428824 31579042 31779220=20 32609218 33249096 34018968=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 3.28-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .