Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Mar 28 2025 09:12:29 AWUS01 KWNH 280912 FFGMPD TXZ000-281400- Mesoscale Precipitation Discussion 0092 NWS Weather Prediction Center College Park MD 511 AM EDT Fri Mar 28 2025 Areas affected...Lower Rio Grande Valley of Texas... Concerning...Heavy rainfall...Flash flooding likely Valid 280915Z - 281400Z SUMMARY...A few more hours of showers/thunderstorms repeating across already flooded locations. Additional 1-3" totals possible, continuing flooding conditions through day break. DISCUSSION...GOES-E WV suite depicts core of MCV/vorticity center lifting north-northeast across South Texas with a trailing shortwave rounding out the bottom of the filling mid to upper level trough that has been persistent across central TX over the past few days. In the process the progressive squall line has moved into the northwest Gulf, but with some weak DPVA upstream, low-level winds have returned to south/southeast from the surface to boundary layer off the western Gulf. GOES-E 3.9um SWIR loop showed low level stratus at the leading edge of the return moisture, modest instability field lifted north but along weakening winds into the 15-25kts range from 925mb VWP in the area. Veered flow across 850-700mb with weak WAA allowed for some convection to refocus and build across Hildalgo to W Cameron county. Weaker flux of still ample deep layer moisture of 1.75-1.9 Total PWat and 1000 J/kg, support rates up to 1.5"/hr but given the veered steering flow aloft will once again allow for cells to train ENE across significantly flooded areas with an additional 1-3" totals expected, likely to maintain ongoing flooding conditions. Hi-Res CAMs continue to struggle with the placement and timing of the evolution of the convection. However, early HRRR runs showed a similar evolution through the Lower Rio Grande Valley but had been about 2 to 2.5 hours too slow with the timing of the squall line and the ongoing redevelopment. Still, the evolution seems to be the best handle on the situation, as such there most recent run has backed off a tad, suggesting the convergence and ascent pattern may be weakening with greater surface to boundary layer winds turning eastward across the Northwest Gulf over the next 3-5 hours finally giving the area of concern a break from these repeated rounds. Given the run to run variability and poor performance from other CAMs, not fully confident that additional convection may maintain at the trailing edge of the low level confluence of the larger cyclonic circulation as it lifts northeast across Northeast Texas later this morning as hinted by the recent RAP runs. Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9r039ww4ec7ioPgjc0BaxaDY5z-eJ8qZZfvOl-7Ncf1gzzlQ41znwbiDnB1-tJWM694W= ENbXJdwOluvoDuKnE-LEeFI$ for graphic product... ATTN...WFO...BRO... ATTN...RFC...WGRFC...NWC... LAT...LON 26969773 26889732 26519720 25989709 25799730=20 25969771 25979800 26129846 26339890 26659872=20 26909818=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) .