Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Sep 24 2025 13:48:47 AWUS01 KWNH 241348 FFGMPD MSZ000-LAZ000-ARZ000-TXZ000-241900- Mesoscale Precipitation Discussion 1130 NWS Weather Prediction Center College Park MD 948 AM EDT Wed Sep 24 2025 Areas affected...Eastern Texas through far Western Mississippi Concerning...Heavy rainfall...Flash flooding possible Valid 241347Z - 241900Z Summary...Clusters of showers and thunderstorms will continue into the afternoon as a cold front approaches from the Northwest. This convection will likely have rain rates of 2-3"/hr, which through training or repeating could produce 2-4" of rain and instances of flash flooding. Discussion...The regional radar mosaic this morning shows clusters of thunderstorms advancing across portions of Louisiana, Arkansas, and eastern Texas. These thunderstorms are developing ahead of a cold front analyzed by WPC moving across Texas, with outflow boundaries from prior thunderstorms driving additional ascent. Synoptically, deep layer ascent is also intensifying across the region as a longwave trough digs slowly across Oklahoma driving height falls, while a jet streak arcs from the Southern Plains into the Appalachians, providing favorable diffluence within the RRQ. Additionally, a wave of low pressure moving along the cold front is resulting in locally accelerated 850mb winds measured to 25-35 kts, providing not only enhanced convergence, but driving more impressive moisture northeast into the region. Thermodynamics remain impressive as well. PWs as measured by GPS and morning 12Z U/A soundings are around 2 inches, above the 90th percentile from the SPC sounding climatology, which is overlapped with MUCAPE as much as 3000 J/kg. The impressive ascent into these robust thermodynamics is producing rainfall rates that are estimated via local radars to be more than 2.5"/hr, resulting in MRMS 1-hr rainfall that has been as high as 2-3" across parts of AR. As the morning progresses, the slow translation east of the cold front and accompanying wave of low pressure into the favorable environment should result in an expansion and intensification of convection, especially from eastern TX into the ArkLaTex region. Although the CAMs differ highly in their evolution and rainfall footprint, recent convective development across eastern TX suggests that activity will ramp up again, and both the HREF neighborhood probabilities and the HRRR 15-min rainfall accumulations indicate rates will surge at times to 2-3"/hr, locally and briefly up to 4"/hr. With 0-6km mean winds aligned to the front, and Corfidi vectors becoming increasingly anti-parallel to this mean wind, at least short term training is likely the next several hours. Although recent rainfall has been modest which is reflected by anomalously dry soils according to NASA SPoRT, any significant training of these intense rates could result in instances of flash flooding the next several hours. Weiss ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!572e6vx4cbw-JQokAdKt_aOfli4n5MxOU8P-IqRKdBxKoPTfdOp9zBRhBSWovxtJ4UBG= o3Vq8fOUoN2_HrwVI4pCkGo$ for graphic product... ATTN...WFO...FWD...HGX...JAN...LZK...MEG...SHV... ATTN...RFC...FWR...ORN...TUA...NWC... LAT...LON 34549143 33539057 32979068 32539137 32119234=20 31769341 31209480 30829545 30719646 31179695=20 31879662 32909532 34369316=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) .