Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Aug 26 2024 14:51:04 AWUS01 KWNH 261450 FFGMPD LAZ000-TXZ000-262050- Mesoscale Precipitation Discussion 0928 NWS Weather Prediction Center College Park MD 1050 AM EDT Mon Aug 26 2024 Areas affected...Middle and Upper Texas Gulf Coast Concerning...Heavy rainfall...Flash flooding possible Valid 261450Z - 262050Z SUMMARY...Scattered slow moving storms within a moist airmass and surrounding a mid to upper low in the western Gulf of Mexico will continue to develop and expand through this afternoon along the Texas Gulf Coast. Localized areas of flash flooding are possible within rainfall rates of 1-3" per hour. DISCUSSION...An upper level low gradually progressing westward across the Gulf of Mexico seen in GOES-East WV-ML is nearing coastal portions of Texas this morning along with numerous slow-moving thunderstorms. GOES-East IR displays cooling cloud tops now occurring along a convergence axis along the TX coast, areas just inland in south-central TX, as well as continuing convection just offshore directly underneath the 500 mb low. Recent RAP analysis depicts PWs over 2" spanning much of the western Gulf Coast, with values over 2.1" centered between Matagorda and Galveston Bay (about +1 standard deviation above the climatological mean per the 00z GEFS). This region is where intense rainfall rates of 1-3" per hour and the potential for localized rainfall totals of 3-4" appear most likely given current radar trends. Advected instability along the northern periphery of the upper low directed into the upper Texas Coast will aid in maintaining updrafts within the moist environment through the afternoon. MLCAPE values over 2000 J/kg along the coast are forecast to expand gradually inland. Brief training of storms are possible due to weak surface flow and coastal convergence. Scattered heavy rain and thunderstorms are also forecast to move inland throughout south-central TX this afternoon as the mid to upper low continues to gradually progress westward Most 12z CAMs highlight localized to scattered rainfall totals of 1-4" within the MPD through 21z, which would lead to isolated areas of flash flooding (particularly urbanized locations) given the 3-hourly FFG values of 3-4". Coverage of heavy rainfall is likely to be the most limiting factor regarding potential flooding impacts. However, 06z HREF neighborhood probabilities of 6-hr rainfall totals exceeding 3" are around 30-40% for much of the immediate coastal regions highlighted. Snell ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-bhdbecirZpnTH1UKGEi7AO9MOELu3KWg39f_MGsNuGT9tz1vEVSbFYOOkDla9DyXxDb= DLAxI04GClCxOoY7qxLBYxc$ for graphic product... ATTN...WFO...CRP...EWX...HGX...LCH... ATTN...RFC...LMRFC...WGRFC...NWC... LAT...LON 29979469 29979388 29809344 29359358 28739491=20 28169585 27639671 27599721 27959759 28739775=20 29339760 29689713 29839634 29909546=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) .