Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Jun 04 2025 00:15:29 AWUS01 KWNH 040014 FFGMPD NMZ000-AZZ000-UTZ000-NVZ000-CAZ000-040613- Mesoscale Precipitation Discussion 0353 NWS Weather Prediction Center College Park MD 814 PM EDT Tue Jun 03 2025 Areas affected...southern California, southern Nevada, northern Arizona, far southern Utah, northwestern/north-central New Mexico Concerning...Heavy rainfall...Flash flooding likely Valid 040013Z - 040613Z Summary...Mature thunderstorms continue to move slowly within an axis from near Los Angeles and the Transverse Ranges eastward to northwestern New Mexico. Spots of 0.5-1.25 inch/hr rain rates are exceeding FFG thresholds in local areas and causing excessive runoff/flood impacts. These impacts should continue on a scattered basis through at least 06Z/10p PDT. Discussion...Abundant surface heating, steep lapse rates aloft, and appreciable moisture content has enabled development of several clusters of slow moving thunderstorms across the discussion area this afternoon. The heaviest downpours have been concentrated across portions of the San Bernardino Mountains eastward to near Las Vegas and adjacent areas of northwestern Arizona, where PW values at or above an inch were noted via mesoanalyses. These cells have prompted occasional flash flood impacts over the last 3-6 hours as well. Models/CAMs suggest that these cells will be primarily diurnally driven and persist through just after sunset before weakening and decreasing in coverage.=20 Flash flood potential is expected to continue during that time. Farther east, a more isolated threat for flash flooding exists across northern New Mexico. Here, moisture/PW values are comparatively lower (around 0.65 inch) and faster flow aloft has enabled slightly faster storm speeds, limiting the amount of rainfall in any one spot. Nevertheless, areas of 0.5 inch/hr rain rates should continue for another 3-5 hours or so (through 05Z/8p MDT) and may occur over burn scars and other sensitive terrain across the region. Eventually, nocturnal surface cooling should aid in decreasing storm intensity/coverage especially after dark. Cook ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5e9pyQVCwIArXpmvlTKWuxw3nrVrHw98niw9jpr7VX2hVazc9PZ_0dw4cyfQ2-P9MlRf= hz85YqqZmNzk0pbL6Hkb9gY$ for graphic product... ATTN...WFO...ABQ...FGZ...HNX...LOX...PSR...REV...SGX...SLC... VEF... ATTN...RFC...FWR...RSA...STR...TUA...NWC... LAT...LON 37871738 37811490 37311357 36791114 36900779=20 36750563 36540468 35940491 35220636 34680802=20 34330965 34551282 34031506 33041581 32631695=20 33231751 33911848 34451950 34611902 35051831=20 36361852 37371883=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) .