784
AWUS01 KWNH 260222
FFGMPD
AZZ000-NVZ000-CAZ000-260730-

Mesoscale Precipitation Discussion 0498
NWS Weather Prediction Center College Park MD
1017 PM EDT Tue Jun 25 2024

Areas affected...Western & Southern AZ...Far Eastern CA...Ext
Southern tip of NV...

Concerning...Heavy rainfall...Flash flooding possible

Valid 260230Z - 260730Z

SUMMARY...Risk for scattered clusters of thunderstorms along/ahead
of outflow boundary may produce 1-2" localized totals and possible
flash flooding incidents through early overnight period.

DISCUSSION...Western AZ...
Favorable upper-level conditions continue to support ongoing
convective clusters.  Western AZ remains within entrance to broad
southwesterly jet along the northwest quadrant of synoptic ridge.
In the lower levels, confluence and gentle upslope is responding
with southerly to southeasterly flow drawing higher
moisture/theta-E air northward on about 10kts of inflow and given
fairly orthogonal intersection with older outflow is likely to
spur further development across W AZ, perhaps into far E CA and S
NV, though instability is a bit weaker given reduced lapse rates.
Still, given deep moisture is over 1.75 to 2" through depth and
flux convergence should allow for clusters to reform.  These
updrafts will have slow/weak northward drift allowing for
increased duration up to 1-2 hrs resulting in spots of 1-2" across
hard pan, perhaps even rugged sloped terrain that may enhance
run-off for possible localized flash flooding conditions through
the early overnight period.

Southeast AZ...
A complex along leading edge of diurnal wave is once again moving
across northern Chihuahua into NE Sonora state in MX.  Higher
unstable air has pooled in proximity to the wave and is starting
to filter through Cochise and Santa Cruz county.  Goes-E 10.3um
and 3.9um imagery shows some scattered developing Tcu and CBs
along this leading impulse.  Surface winds across E Pima county
appear to be weakly responding and increasing moisture flux up
through the lower valley/Sonoran Desert.  As such, additional
convective development may expand W and NW with time with similar
1-2" localized totals and possible localized flash flooding as
well.

Gallina

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...FGZ...PSR...TWC...VEF...

ATTN...RFC...CBRFC...CNRFC...NWC...

LAT...LON   36061483 36041411 35401331 34021212 33111088
            32021024 31371102 32471352 33491462 34431517
            35251539 35701525