045
AWUS01 KWNH 092036
FFGMPD
AZZ000-UTZ000-100200-

Mesoscale Precipitation Discussion 1172
NWS Weather Prediction Center College Park MD
436 PM EDT Thu Oct 09 2025

Areas affected...Northern Arizona...Southern Utah...

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

Valid 092035Z - 100200Z

SUMMARY...Increasing coverage of small core thunderstorms embedded
with moderate shower activity.  Localized .5"-.75"/hr rates over
very flashy basins and multiple south to north rain bands may
allow for some cross tracks and totals of 1-1.5" resulting in
localized flash flooding conditions.

DISCUSSION...Environment is starting to show initial signs of
waves/bands of convective activity expected through the afternoon.
 CIRA LPW and RAP analysis also denote leading edge of enhanced
subtropical moisture has grown deep enough to over-top the
Mogollon Rim and is lifting northward through the San Francisco
Plateau, Tds in the upper 40s to mid-50s have been noted and
pockets of total PWats over 1" have started to be
observed/analyzed.  Clear skies has provided ample insolation to
support increased SBCAPEs 750-1000+ J/kg with rapidly reducing
CINH capping across the Plateau.

GOES-W WV shows bulge of ideally anticyclonically curved
outflow/sub-tropical jet from Priscilla, as well as broadening
diffluence to its northwest under influence of the approaching
northern flow/polar jet streak.  Current divergence is small but
effective for the initial band of showers along the AZ/UT border
with recent uptick in embedded convective showers.  The enhanced
moisture flux and weak convergence associated with the broad scale
ascent appears to support some rates of .5"/hr so far.

As the evening progresses, the divergence pattern is expected to
increase with approach of embedded waves through the sub-tropical
stream.  This will increase overall coverage and the smaller cored
convection is expected to broaden with upstream redevelopment
along the Mongollon Rim and volcanic peaks within the broader
Plateau.  General north to north-northeast propagation will allow
for the potential for multiple bands resulting in random
intersection with prior rainfall footprints.  Localized 1-1.5" are
possible, though most of the area of concern has naturally very
low FFG at .5-1"/hr (especially in south-central and SE Utah) and
less than 1"/3hrs.   While overall coverage/totals are not
expected to be sizable, a random scatter shot of widely scattered
incidents of flash flooding are clearly possible.

Gallina

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

ATTN...WFO...FGZ...GJT...SLC...VEF...

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

LAT...LON   39491037 38740955 37710952 36910977 35921049
            35061158 34641310 35111391 36261394 37071312
            37621245 38261202 39211140