Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Oct 26 2025 02:12:02 AWUS01 KWNH 260211 FFGMPD MSZ000-LAZ000-TXZ000-260800- Mesoscale Precipitation Discussion 1213 NWS Weather Prediction Center College Park MD 1011 PM EDT Sat Oct 25 2025 Areas affected...Southeast TX...Much of Western & Central LA...Far Southwest MS... Concerning...Heavy rainfall...Flash flooding possible Valid 260210Z - 260800Z SUMMARY...Expanding convective lines to merge/converge with some internal cell training/repeating expected. Uptick in moisture flux will increase rainfall efficiency and support up to 2"/hr rates. SW to NE swath of 2-4" totals may result in scattered incidents of flash flooding overnight. DISCUSSION...GOES-E WV suite shows broad, symmetric and well defined closed low dominating the Southern Plains encroaching on the Lower Mississippi River Valley as the lead height-falls has pressed through into MS toward W AL. The secondary/wrap around energy and core of the upper-low is currently tracking along the Red River with another internal jet streak and associated upper-level divergence and DPVA for broad scale ascent across the southeast quadrant of the circulation across E TX into LA. EIR loop shows scattered overshooting tops along a west to east axis of convergence along a pre-frontal trough dropping southeast becoming more orientated to the deeper layer southwesterly steering flow. However, the favorable ascent pattern has positive influence across much of SE TX into LA, where low level cu-field noted in 3.9um and regional RADAR mosaic are showing developing narrow cored thunderstorms broadly from the central TX coast into central LA ahead of the main line. RAP/CIRA LPW analysis denotes core of higher theta-E air and moisture values of .75-1" in the surface to 850mb layer across the TX Coastal Plain into SW LA and up the MS River to near the AR border. Highest buoyancy air also tends to reside closer to the coastal region with MLCAPE up to 1500 J/kg along and downstream of the main line. As such, additional downstream cells are expanding/developing in the next few hours with broad LLJ over the Western Gulf becoming increasingly confluent increasing overall convergence for expanding convective development. In addition, this flux of 1.5-1.8" total PWats (mainly below 700mb) and LLJ ramping up to 25-30kts over the next few hours will support broadening updrafts capable of 2"/hr. As the DPVA further drops southeast, orientation of broader SW to NE wedge of convective complex will support embedded northeast motions for short-term training/repeating as the overall propagation is steadily east-southeast. Prolonged moderate rainfall with these embedded strongest bursts should allow for a broader area of 2"+ rainfall with localized totals of 4"+ through 09z with best probabilities located from SW to central LA pushing toward SW MS toward the end of the period.=20 Of note toward the end of the valid time (, the surface warm front along the MS is likely to be steepened through depth as the strength of the easterly flow across the Tennessee Valley and central AL undercuts and increases FGEN/ascent plane for isentropic development. Hydrologically, the area has been relatively dry though this morning's initial convective line has moistened up some of the upper soil columns for greater infiltration and naturally higher FFG due to sandier profiles ( 2-3"/hr and 3-4.5"/3hrs), should help to limit flooding potential. However, scattered to widely scattered flash flooding will remain possible, especially in/near prone urban centers. Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5d1ibIQqoy2aXcOcc4_EYbSlKQJXhbqWQzWMesf7IxipAbB29iD-dZzFPhGt3NaKn0XU= cjT68MhRi8kzHLaER4cLPCk$ for graphic product... ATTN...WFO...EWX...HGX...JAN...LCH...LIX...SHV... ATTN...RFC...FWR...ORN...NWC... LAT...LON 32779209 32569099 31869082 30959140 30189242=20 29479407 29069486 28529598 28809650 29909716=20 30869599 31439529 32319423 32699347=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) .