Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Aug 31 2025 16:47:49 AWUS01 KWNH 311647 FFGMPD TXZ000-312100- Mesoscale Precipitation Discussion 1038 NWS Weather Prediction Center College Park MD 1246 PM EDT Sun Aug 31 2025 Areas affected...southeastern TX Concerning...Heavy rainfall...Flash flooding possible Valid 311645Z - 312100Z SUMMARY...Isolated, mostly urban, flash flooding will be possible across portions of southeastern TX over the next 3-4 hours with hourly rainfall of 1 to 3 inches. DISCUSSION...Widely scattered showers and thunderstorms were beginning to form over the southeastern TX Coastal Plain as of 1620Z, in advance of a small, forward propagating MCS located in the College Station/Huntsville vicinity of southeastern/eastern TX. An MCV was apparent near I-45, tracking toward the ESE into an instability minimum estimated over east TX. Therefore, there is no significant concern of flash flooding for locations near the Sabine River which has received heavy rain yesterday. However, the strongest convection was located along the southern flank of the MCS in the form of a forward propagating linear segment, advancing toward the south at roughly 20 kt, into a region containing 1000-2000 J/kg MLCAPE and 2.3 to 2.5 inch PWATs via 16Z SPC mesoanalysis data. The unstable environment and mesoscale boundary interactions should contribute to at least isolated additional convective development between the Gulf Coast and southward advancing line of thunderstorms from the MCS over the next few hours. Deeper layer mean winds were quite weak from roughly I-10 and southward, at ~5 kt, which will contribute to slow cell motions in advance of the propagating MCS. There will be an isolated flash flood concern where slow moving cells are overtaken by the gradually weakening, but still notable, propagating line of thunderstorms where 1 to 3 inches of rain in an hour will be possible. Overlap of these higher rates with urban locations, including the Houston metro, may lead to isolated flash flooding through 21Z. Otto ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7PDV2hPP86BUOtrG4Iw8GzA-qLFND4vfN_37s-6oCiNocSyHEHA2oxoIJBTa09UX6zXw= _LGiOTRniZimIUzDsUDydUg$ for graphic product... ATTN...WFO...EWX...HGX...LCH... ATTN...RFC...FWR...NWC... LAT...LON 30739468 29749411 29069466 28649568 28799648=20 29519697 30129681 30649580=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) .