Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Jun 12 2025 03:07:59 AWUS01 KWNH 120307 FFGMPD TXZ000-120730- Mesoscale Precipitation Discussion 0422 NWS Weather Prediction Center College Park MD 1107 PM EDT Wed Jun 11 2025 Areas affected...central TX Concerning...Heavy rainfall...Flash flooding likely Valid 120304Z - 120730Z Summary...Areas of heavy rain from slow moving thunderstorms are likely to produce scattered areas of flash flooding across portions of central TX through 07Z. The threat of flash flooding is expected to increase toward the south with time and a few spots of 3 to 6+ inches may lead to significant/considerable impacts. Discussion...GOES East water vapor imagery showed the southern end of a mid to upper-level low over west-central TX along the northern end of the Edwards Plateau near the Colorado River at 0230Z. Radar imagery showed scattered thunderstorms from the Edwards Plateau, northward to I-20 and as far east as I-35. MRMS hourly rainfall was topping out near near 4 inches just north of Waco while other cells to the west of I-35 and near I-20 showed peak hourly rainfall of 1-2 inches. The environment as sampled by the 00Z FWD RAOB and depicted on the 02Z SPC mesooanalysis showed modest mid-level lapse rates of 6.2 C/km, tall/skinny CAPE with 500-1500 J/kg mixed layer instability and PWs that ranged from 1.7 to 1.9 inches across the region. The 00Z FWD sounding also showed a wet-bulb zero height of 12.6 kft, indicative of the potential for warm rain processes. Over the next 3-5 hours, the southern lobe of the mid-level low will slowly edge east while 925-850 mb layer flow increases from southern to eastern TX into the 20 to 30+ kt range. Slow moving cells will continue across the region with the slowest motions closest to the mid-level low/trough placement...west of the Metroplex to just north of the Edwards Plateau. By 06Z (1 AM CDT), the increasing magnitude of the low level flow and low level convergence along its leading edge should allow for expanding convective development to focus farther southtoward San Antonio while slowly expanding east across the I-35 corridor. Cells will show a mixture of slow movement, back-building/training and merging which will be capable of 2 to 3+ in/hr rainfall. Given recent heavy rain and the expectation of localized additional totals of 3 to 6+ inches through 07Z to 08Z, scattered areas of flash flooding will be likely. 01Z and 02Z WoFS indicated the greatest potential for 3+ inches of rain over the following 6 hours to be from near San Antonio, northward to just west of Austin (50-80 percent probs). In addition, 90th percentile data (reasonable worst case scenario) showed 10 to 12 inches of rain in some of these same locations. While 10 to 12 inches of rain may be a high bar to reach, even 50th percentile QPF values of 4-5 inches from the WoFS is noteworthy. These rains may lead to locally significant/considerable flash flood impacts, especially given the sensitive terrain of the TX Hill Country. Otto ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8YndtCGAs8KoCkAgOuZoFZR-gu-Fgd_InPfDR65XJRHG_XTfRp-j-Zl0TMax_ELjbBQb= oL9gywSBuQKOh6os3q1vc4A$ for graphic product... ATTN...WFO...CRP...EWX...FWD...HGX...SJT... ATTN...RFC...FWR...NWC... LAT...LON 33139750 32209651 30479643 29239715 28719821=20 28699924 29249992 30859989 32009901 32969858=20 =20=20=20=20=20=20=20=20=20=20=20=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) .