Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Jun 10 2023 22:05:13 AWUS01 KWNH 102205 FFGMPD LAZ000-TXZ000-110357- Mesoscale Precipitation Discussion 0460 NWS Weather Prediction Center College Park MD 604 PM EDT Sat Jun 10 2023 Areas affected...central/east Texas and far southwestern Louisiana Concerning...Heavy rainfall...Flash flooding possible Valid 102157Z - 110357Z Summary...Vigorous convection forming on the upstream flank of a mature Louisiana MCS should result in localized flash flood potential across the discussion area through 03Z. Discussion...A mature MCS over southwestern Louisiana has began to surge southeastward along the Sabine River Valley and vicinity over the past couple hours. This has resulted in southwestward movement of an outflow boundary across east-central Texas and the DFW Metroplex toward a very unstable airmass with 4000 J/kg MLCAPE, 1.8 inch PW values, and steep (7+ C/km) lapse rates aloft. Robust thunderstorm development has begun along and just north of the outflow boundary in east Texas, and with steering flow aloft roughly parallel to the outflow boundary, storms have began to train locally. MRMS-estimated rain rates are in the 1-2 inch/hr range, with local peaks around 3 inch/hr with the intense cluster located roughly 30 miles southeast of Dallas. Despite these heavy rain rates, FFG thresholds in most of the discussion area are in the 2.5-4 inch/hr range, suggesting that ground conditions may not support a widespread flash flood risk except for on a localized basis near sensitive/urbanized surfaces. Some concern exists that the presence of extreme instability, an outflow boundary, and vertical shear profiles supporting organization/marginal supercellular structures could result in one or two cells or clusters producing extreme rain rates for periods of time - particularly in the western end of the complex from Dallas to Tyler to College Station. This process may be occurring near Corsicana currently (2150Z) and could repeat on a localized basis through 03Z tonight. Although local 3-5 inch rainfall amounts cannot be completely ruled out in this scenario, overall thinking is that the southward surge of a cold pool associated with the mature MCS downstream and renewed convection near the outflow should result in a steady southward translation of axes of heavier rain through the early evening. High FFG thresholds should also keep the flash flood risk isolated through the early evening. Cook ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!4Xpt6QX4OddtvAJNuRRroFkSfopX6rgimLalqqyoVqaxn8-c4mkHr_ESe9EzA1YOb493= zWNxdXHm1X8QANmZZLWBRAI$ for graphic product... ATTN...WFO...EWX...FWD...HGX...LCH...SHV... ATTN...RFC...LMRFC...WGRFC...NWC... LAT...LON 33099751 32979673 32609544 32349421 32009293=20 31389231 30609223 30269260 30059399 29879567=20 29999671 30939748 31949771=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 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .