Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Apr 30 2025 19:27:39 AWUS01 KWNH 301927 FFGMPD LAZ000-ARZ000-TXZ000-OKZ000-010125- Mesoscale Precipitation Discussion 0203 NWS Weather Prediction Center College Park MD 325 PM EDT Wed Apr 30 2025 Areas affected...Central to Northeast TX...Far Southwest AR...Far Northwest LA Concerning...Heavy rainfall...Flash flooding likely Valid 301925Z - 010125Z SUMMARY...A complex of heavy showers and thunderstorms will continue to gradually settle south and east going through the afternoon and early evening hours. Intense rainfall rates and storm totals will likely promote additional areas of flash flooding which will include locally considerable/significant urban flash flooding impacts. DISCUSSION...The afternoon GOES-E visible satellite imagery shows a substantial amount of CU/TCU development across central to northeast TX out ahead of a well-defined and long-lived MCS that has been transiting northern TX and eastern OK over the last several hours. The warm-sector airmass with the aid of strong diurnal heating and a moisture-laden boundary layer with surface dewpoints in the upper 60s to low 70s is affording MLCAPE values as high as 1500 to 3000 J/kg. This includes the Austin to Waco corridor on northeastward up into the Tyler and Longview vicinity. A combination of strong instability and enhanced moisture flux convergence with the aid of a southerly low-level jet of 40 to 50 kts will continue to favor a well-organized southern flank of the larger scale convective mass. The convergent nature of the moist low-level wind field and with favorable low to mid-level shear profiles (0-3 km bulk shear of 30 to 40 kts) should continue to sustain enhanced convective cores with rainfall rates reaching as high as 1 to 3 inches/hour. The concern going into the evening hours will be the increasing threat for the southwest flank of the convective line to begin slowing down as upstream mid-level height falls begin to increasingly overspread the broader southern Plains region, and with the deeper layer flow becoming more aligned with the leading edge of the surface cold pool/outflow boundary orientation. Cell-training concerns with backbuilding convection may extend in time as far southwest as the Austin metropolitan area itself, but greater short-term concerns are expected along the Waco to Tyler corridor and stretching east through Tyler and Longview. Some of the convection will also advance into far southwest AR and northwest LA, but generally the heaviest rainfall should be for areas farther down to the southwest over central to northeast TX. Recent runs of the HRRR/RRFS guidance and also the experimental WoFS indicate potential for as much as 3 to 6 inches of rain where the greatest cell-training concerns set up, and this will promote additional areas of flash flooding with a concern at least locally for considerable/significant urban flash flooding impacts. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8Uxh8F4G4WVKve7VdDUzMV8SxxjdxMM54Y7QlaXv6HZeu32842o5oB_xYj8hvsheO8ZB= i8bpEOrjQJe_jd4fBqjCKpk$ for graphic product... ATTN...WFO...EWX...FWD...HGX...OUN...SHV...SJT...TSA... ATTN...RFC...ABRFC...LMRFC...WGRFC...NWC... LAT...LON 34059415 33699330 32959312 32199366 31049538=20 30359680 30319798 30969847 31949822 33459674=20 34019538=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) .