Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Sep 24 2025 08:42:14 AWUS01 KWNH 240842 FFGMPD MSZ000-LAZ000-ARZ000-TXZ000-OKZ000-241415- Mesoscale Precipitation Discussion 1129 NWS Weather Prediction Center College Park MD 441 AM EDT Wed Sep 24 2025 Areas affected...Southern AR...Northern LA...Far Western MS...Ext Southeast OK...Ext Northeast TX... Concerning...Heavy rainfall...Flash flooding possible Valid 240840Z - 241415Z SUMMARY...Strong moisture flux and rates over 2"/hr with short-term training poses streaks of 2-4" totals and possible incidents of flash flooding through early morning. DISCUSSION...Regional RADAR mosaic continues to show stronger clusters of thunderstorms extending west to east along older convectively reinforced boundaries across central to southern AR and into NW MS. Broad southwesterly LLJ continues to flux enhanced lower level anomalous moisture to intersect with the boundary to maintain isentropic ascent, to tap skinny but still unstable profiles with 2000-2500 J/kg of CAPE. The southwesterly flux combined with very slow southward drift of the boundary has allowed for overall moisture profile to reach 2-2.25" total PWat values and raise warm cloud layers a few extra thousand feet, increasingly efficient warm cloud rainfall generation, supporting rates of 2-2.5"/hr.=20 GOES-E WV suite shows base of the main core, upper-low continuing to advance across the TX Panhandle, this has delayed the advancement of the cold front across eastern OK, further allowing the length of the isentropic ascent to be long enough to allow for repeating/training for those scattered clusters. LLJ winds are expected to increase to 25-30kts but also veer a bit more to reduce angle of intersection with the effective isentropic boundary toward daybreak and may further reduce overall coverage. Still, the deep layer steering flow will be just a bit south of due east allowing for short-term training/repeating to remain across southern Arkansas and far Northern Louisiana and perhaps into far western MS after 12z. Streaks of 2-4" are possible but this will also be crossing areas that have been dry for a prolonged period and higher FFG values in general. NASA SPoRT LIS 0-40cm relative soil moisture values are generally below 30% with some as low as 10% in main river valleys. Intense rates initially up to 2.5"/hr may not have much time to infiltrate and could have above normal run off, so any flash flooding incidents are likely to be more widely scattered in nature and therefore the risk is considered possible through 14z. Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-fBZGZfQ8KmwaZf1e3ZpdkCGVGFkwPwh4oASsTypnjtvIng4Z5YvxODWCTZ66vXGtinp= -ltHPoal8_P6C_DTFXjT89I$ for graphic product... ATTN...WFO...JAN...LZK...SHV... ATTN...RFC...ORN...TUA...NWC... LAT...LON 34589183 34159116 33239042 32699067 32609141=20 32609301 32999465 33659507 34059491 34409418=20 34289297=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) .