123
AWUS01 KWNH 120812
FFGMPD
AZZ000-121411-

Mesoscale Precipitation Discussion 1185
NWS Weather Prediction Center College Park MD
411 AM EDT Sun Oct 12 2025

Areas affected...southern/central Arizona

Concerning...Heavy rainfall...Flash flooding likely

Valid 120811Z - 121411Z

Summary...Showers and isolated thunderstorms will continue to
increase in coverage through at least 13Z/7a MST this morning.
Areas of flash flooding are expected during that timeframe.

Discussion...Larger-scale ascent was beginning to overspread much
of the Southwest due to a stout mid-level wave centered over
Nevada and northwestern Utah.  Meanwhile, a pool of 1000 J/kg
SBCAPE and weak inhibition has supported development of scattered
thunderstorms from the Phoenix area east to near Globe.  The
storms are embedded in a moist airmass (1.1-1.5 inch PW values),
supporting rain rates at or above 1 inch/hr in the strongest
cells.  Relatively quick movement has been noted owing to 40 knots
of mean steering flow.  However, as cells continue to expand in
coverage and intensity, local mergers and backbuilding should also
bump rain rates to above 1 inch/hr at times.   The flash flood
risk will increase as a result.

Models/CAMs suggest that the greatest concentration of
thunderstorm activity will reside along and just south of the
Mogollon Rim through 13Z/7a MST this morning.  This includes the
Phoenix Metro area.  Much of the discussion area remains well
ahead of any low-level boundaries that could stabilize this
airmass, and with continued ascent/height falls over the region,
flash flood potential will likely extend beyond 13Z/7a MST.  Both
urban and sensitive/low-lying areas will have the greatest flash
flood risk.

Cook

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

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

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

LAT...LON   34471072 34050941 32830932 31381045 31801316
            32601435 33471431 33951357 34201246