Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Mar 26 2025 23:19:59 AWUS01 KWNH 262319 FFGMPD TXZ000-270518- Mesoscale Precipitation Discussion 0086 NWS Weather Prediction Center College Park MD 719 PM EDT Wed Mar 26 2025 Areas affected...portions of south Texas Concerning...Heavy rainfall...Flash flooding likely Valid 262318Z - 270518Z Summary...Areas of heavy rainfall continue to move slowly across the discussion area, with redevelopment of deep/intense convection noted along/just west of the Rio Grande recently. Flash flood potential (locally significant) should continue through 05Z/11p CDT and likely beyond. Discussion...Over the past 6 hours, scattered to numerous thunderstorm activity has produced areas of 1-5 inch rainfall amounts - highest northwest of Corpus Christi and northwest of McAllen. Prior dry conditions and high FFGs suggested that these rainfall totals have likely resulted only minimal impacts so far, though wetting soils should gradually result in the region becoming more susceptible to flash flooding as additional rainfall develops across the region tonight. Meanwhile, radar/satellite mosaic imagery indicates redeveloping/strengthening convection along and either side of the Rio Grande Valley, with additional strengthening storms located just north of Corpus Christi. Wind fields aloft have strengthened across the discussion area in tandem with better ascent/lift, which is the likely culprit for the recent increase in convective coverage. Increased wind shear has enabled a few of the convective structures toexhibit right/deviant motion with speeds as slow as 5-10 knots and rain rates exceeding 2 inches/hr. Over time, concern exists that convection near the Rio Grande could grow upscale into one or more convective complexes. These complexes will move very slowly while continuing to exhibit embedded rotation and occasional cell mergers that should enhance rain rates. Localized areas of 3-5 inch rainfall totals are expected, and significant flash flooding could become a great concern if higher rain rates were to materialize in sensitive/urbanized portions of the discussion area. A secondary concern for upscale growth/backbuilding exists near/just north of Corpus Christi where low-level confluence exists on the northern extent of 20-25 kt 850mb flow. A few of these areas have already experienced 2-5 inch rainfall totals today. Additional rainfall could result in flash flooding especially if a more persistent convective band could become established. Cook ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6rl1j1YZhZDJqe53V_RjJH2MXwSfghCpBfsOtGddV2TNxyeRFOEiI-lCNUsmSupXuQq2= kaxU-Zb1wQ7Hr3gbZt1RxVU$ for graphic product... ATTN...WFO...BRO...CRP...EWX...HGX...SJT... ATTN...RFC...WGRFC...NWC... LAT...LON 30599832 30329724 29809654 29259617 28569631=20 27869674 27099719 26499730 26349770 26379853=20 26649920 27329952 28049993 28730053 29050080=20 29620131 30180112 30559991=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 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .