Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Jun 09 2025 04:51:54 AWUS01 KWNH 090450 FFGMPD LAZ000-ARZ000-TXZ000-OKZ000-091030- Mesoscale Precipitation Discussion 0407 NWS Weather Prediction Center College Park MD 1249 AM EDT Mon Jun 09 2025 Areas affected...Much of northern & Central TX...Northwest LA...Southwest AR... Concerning...Heavy rainfall...Flash flooding likely Valid 090450Z - 091030Z SUMMARY...Very large, progressive MCS. Greater duration of intense rain-rates along the warm advective wing on the northeast side as well as along the flanking line due to repeating pose best potential for 2-3" totals much in very short-duration. DISCUSSION...GOES-E WV suite shows a large dual clustered MCS across the Central Red River Valley back into the Rolling Plains/Big Country of Texas within a highly diffluent portion of the mid to upper-level flow at the base of a broad, strong synoptic low. This divergent pattern combined with a very moist/unstable environment has supported a strong MCV located at the northeast side of the complex in SE OK, quickly shifting east-southeast. Given the secondary explosive convective development a secondary weaker MCV can be seen further southwest near KMWL with a strong/broad bowing segement connecting the two features as an effective cold front ahead of the northern strong 1013mb meso-high. Further upstream, left exit dynamics and southerly inflow from the Pecos river valley shows a third cluster/linear convective complex acting as a caboose to the overall complex, sweeping through with another strong burst of intense rainfall rates (though equally progressive given the downward mixing of strong flow aloft). Overall the deep layer flow with the diffluence as supported a very progressive southeastward propagation that is starting to limit overall duration of the most intense rain-rates. CIRA LPW and overall Total PWAT animation shows the complex is propagating into slightly drier overall environment through depth, though it continues to currently ingest 2-2.25" total PWats allowing for efficient rates over 2-3"/hr...yet, the quickness is generally limiting the initial burst to about 1-1.5" in 15-30 minutes, with broad moderate shield precip adding an additional .5-1" through the main line. However, southerly inflow on broad 20-25kt LLJ is advecting this drier and lower theta-E air, so rates should continue to diminish with greater dry air and forward propagation expected, reducing the overall flash flooding potential, especially as the convection moves off into the Heart of Texas and into NW LA where FFG values are over 2-2.5"/hr, making FF risk limited to urban areas. With that stated, there will remain two axes of increased rainfall duration: 1) Precursory to the squall line WAA downshear of the MCV center across NE TX into far NW LA/SW AR increasing overall duration and training. Expected totals of 2-3" are probable with an isolated spot of 4" possible. MCV may also slow and rotate northeastward further increasing duration of this training axis.=20 2) The other is along the flanking line of the overall complex that is favorably oriented from WNW to ESE fairly parallel to the deep layer steering of the MCS. In addition, south to south-southwesterly isentropic ascent may help for additional development along the outflow boundary...though with lower unstable and moisture environment, extending the duration of thunderstorm activity and repeat/training will have the greatest potential for those 2-3" totals and continue scattered ongoing flooding in the southern Big Country into northeast Hill country as the trailing 'caboose' linear complex slides through out of the southern Rolling Plains. So all in all, the coverage of flash flooding will be reducing with a few axes of enhanced risk and given the ongoing flash flooding with upstream rainfall likely...flash flooding will remain likely through 10z, but reducing becoming more widely scattered in nature eventually becoming only an urban concern further south and east.=20 Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7iZ9QbBIW8NgwOmIRWKr69Fd02TdQRo2MD-wLx90BpK1HGllYPUNay--4nuOk1QAPLeE= 0s1vLBCqICnIDVyGfl54Lvs$ for graphic product... ATTN...WFO...FWD...HGX...LUB...LZK...MAF...SHV...SJT... ATTN...RFC...FWR...ORN...TUA...NWC... LAT...LON 34069465 33549339 33339303 32979215 32119211=20 31679258 31579339 31259461 30729641 30989757=20 31739974 32200062 32740093 33200032 33219972=20 33099877 32919765 32949610 33329553 33909516=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) .