Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Oct 26 2025 06:45:33 AWUS01 KWNH 260645 FFGMPD MSZ000-LAZ000-ARZ000-261230- Mesoscale Precipitation Discussion 1214 NWS Weather Prediction Center College Park MD 245 AM EDT Sun Oct 26 2025 Areas affected...Lower Mississippi River Valley... Concerning...Heavy rainfall...Flash flooding possible Valid 260645Z - 261230Z SUMMARY...Large MCS cluster will continue to produce 1.5-2"/hr rates and streaks of 2-3.5" totals as it progresses across the Lower MS River Valley through early morning. Scattered incidents of localized flash flooding remain possible, especially near urban/poor drainage areas. DISCUSSION...GOES-E WV suite shows slightly unbalanced closed low has core of vorticity swinging with weak negative tilt from the center in SE OK across central LA. Further aloft, nearly ideal diffluent dual jet structure is providing about 30-45 degrees of split and strong divergence aloft to evacuate and maintain broad meso-scale ascent along and downstream of the shortwave trof.=20 Regional RADAR mosaic denotes a weak MCV-like wave riding northeastward along the western side of the progressive squall-line located just west of ESF. Low to mid-level flow continues to respond with strong LLJ of 20-30kts extending from the upper TX coast through the Mouth of the MS all confluent downstream of this wave. Total PWats are nearing 2" given the overall piling of low to mid-level moisture and wedge of WAA remains fairly unstable with uncapped MLCAPE ranging from 500 J/kg up to the AR/MS/LA border and as high as 1500 J/kg south of Baton Rouge. As such, the strong moisture flux will maintain 1.75"/hr rates with occasional uptick toward 2"/hr where storm scale convergence is maximized.=20 While the upper-low still is advancing at a solid eastward progression, the deep layer steering flow is starting to shift from SW-NE toward a more S to NNE angle. Downstream training/repeating will continue to allow for 2-3.5" streaks of rainfall in a 2-3 hour period generally between I-20 and I-10 mainly as the instability reduces further north with time. More scattered but stronger cells may be capable of slightly higher rates, but duration is likely to be a bit more limited in/along the I-10 corridor.=20=20 Hydrologically, FFG is 2-3"/hr (lower north of I-20) and 3-4"/3hrs, so overall totals will be near those values suggesting scattered localized flash flooding remains possible with highest risk of flash flooding in urban locales due to impermeable surfaces and higher runoff. So all considered, flash flooding is considered possible through 12z.=20 Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!67Am17KXkXDdRIACj7ZxMsXJ217SGU2qQRBq71MGCB2Dw2JxLjp0OCR6bYw0QKEfeUOt= vQIX0lmai_G2QxP21xKO610$ for graphic product... ATTN...WFO...JAN...LCH...LIX...SHV... ATTN...RFC...ORN...NWC... LAT...LON 33469015 33158953 32578923 31398933 29848973=20 28939002 29019097 29619317 30579278 31869218=20 33109162 33419113=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) .