AWUS01 KWNH 121955
FFGMPD
NMZ000-AZZ000-130100-

Mesoscale Precipitation Discussion 1075
NWS Weather Prediction Center College Park MD
354 PM EDT Fri Sep 12 2025

Areas affected...Southeast Arizona...Southwest New Mexico...

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

Valid 121955Z - 130100Z

SUMMARY...Increasing convective coverage and eventually rainfall
rates.  Isolated rates of 1-1.5" and scattered spots of 2" may
pose localized flash flooding conditions through evening.

DISCUSSION...CIRA LPW shows subtropical moisture plume from
850-500mb core along and just south of the US/Mexico border
between Santa Cruz county, AZ and central Dona Ana county, NM
extending northward along the AZ/NM within strong southerly
confluent deep layer flow.   Deep layer bulk shear, remains strong
with 35-45kts mainly along the upwind edge in SE AZ as strong
upper-level flow slowly approaches from the west.  The base of the
strong upper-level trough is also ejecting a upper-level jet
streak to further support large scale ascent and divergence aloft
for thunderstorms that do develop.

Nearly full insolation being well south of mid to upper-level
cloud coverge due to the exiting shortwave over N AZ/SE UT, has
allowed temperatures to rise into the 90s across the lower valley
and through the mid to upper 80s into the slightly higher
topography along and south of the Mogollon Rim in SE AZ/SW NM. 
MLCAPEs of 1500-2500 J/kg will support strong updraft developing
and isobaric influenced moisture flux to any even weakly rotating
updrafts.  Given Tds in the 60s and the overall Total PWat values
of 1.25 to 1.5", should support some localized 1-1.25"/hr totals
(as instantaneous rates would be well over 2".  Deep layer flow
may reduce residency at a given location, but with the upstream
forcing remaining strong and slowly ejecting, should support
back-building/upstream flank development to support
repeating/training locally.  As such, spots of 1.5-2" in 1-3 hours
are likely to scattered across the area of concern.   Given
rugged, hard-pan soil conditions across many locations, FFG values
are naturally below these hourly rates and therefore localized
flash flooding conditions are considered possible through the
remainder of the evening across SE AZ/SW NM.

Gallina

ATTN...WFO...ABQ...EPZ...FGZ...PSR...TWC...

ATTN...RFC...FWR...STR...NWC...

LAT...LON   33900782 33220739 31900720 31700762 31630808 
            31210816 31170923 31231101 31851145 33381091 
            33801000 

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