Mesoscale Precipitation Discussion 1233
NWS Weather Prediction Center College Park MD
1010 PM EDT Wed Sep 09 2026

Areas affected...far western TX into southwestern NM into
southeastern AZ

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

Valid 100209Z - 100615Z

SUMMARY...Lingering monsoon convection will maintain a localized
flash flood threat across portions of far western TX into
southwestern NM and southeastern AZ for another 3-4 hours. High
sub-hourly rain rates will produce isolated additional totals of 1
to 2 inches.

DISCUSSION...0150Z GOES infrared satellite and GLM imagery showed
scattered thunderstorms advancing south across southwestern NM and
WSW over southeastern AZ. Lingering instability of 500 to 1000
J/kg (locally higher as seen on the 00Z EPZ sounding) was located
from western TX into southwestern NM and portions of southeastern
AZ. The storms were moving generally south to southwest following
the deeper layer mean flow around a mid to upper level ridge
centered over west-central AZ. Cell motions were also following
outflow progression, as noted in western Cochise into eastern
Pima/Santa Cruz counties where 15-minute rainfall rates of 0.5 to
1.0 inches have been observed.

Expectations are for storms to continue advancing downstream
(west-southwest to southwest across southeastern AZ and southward
in NM) over the next few hours with localized high sub-hourly rain
rates. The available moisture (1.3 to 1.7 inch PWs per recent GPS
data) will continue to support localized 15-minute rainfall of 0.5
to 1.0 inches and isolated storm totals of 1 to 2 inches. These
higher rates may result in flooding of low lying and urban areas,
as well as other locations of poor drainage. Beyond 06Z, the flash
flood threat is expected to diminish due to a loss of instability
and/or translation of storms into Mexico.

Otto

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

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

LAT...LON   33981082 33521038 33150975 32580939 32320879
            32390831 32740744 32800707 32720657 32350573
            31960541 31150579 31580683 31570783 31180804
            31090867 31090952 31131083 31201136 31781164
            32841163 33561147 33871121