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. 
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

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
            36750563 36540468 35940491 35220636 34680802
            34330965 34551282 34031506 33041581 32631695
            33231751 33911848 34451950 34611902 35051831
            36361852 37371883