383
AWUS01 KWNH 121402
FFGMPD
NMZ000-AZZ000-121830-

Mesoscale Precipitation Discussion 1187
NWS Weather Prediction Center College Park MD
1001 AM EDT Sun Oct 12 2025

Areas affected...central/southern AZ into western NM

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

Valid 121400Z - 121830Z

SUMMARY...Scattered Thunderstorms are likely to continue a few
areas of flash flooding across central/southern AZ over the next
3-5 hours, possibly extending into western NM. Hourly rainfall
over 1 inch will be found within areas of training.

DISCUSSION...1330Z radar imagery across south-central AZ showed
scattered thunderstorms, with a history of backbuilding and
training, despite individual cell motions off toward the ENE at
20-30 kt. OSPO ALPW imagery showed that the cells were located
just ahead of a slow moving, north-south oriented, 850-700 mb
moisture gradient found over the lower CO River Valley with
notable directional shear between the KYUX and KIWA 850 mb wind
vectors. The moisture plume over AZ remained anomalously high with
contributions from former T.C. Raymond in the eastern Pacific. SPC
mesoanalysis data from 12Z estimated PWAT values between 1.0 and
1.5 inches over the southern half of AZ along with 500-1000 J/kg
MLCAPE over south-central to southwestern AZ. In addition, AZ was
situated within the right-entrance region of a 130+ kt upper level
jet max extending from southern NV into northwestern CO.

RAP forecasts over the next 3-6 hours show weakening 850-700 mb
moisture transport into southern AZ but some increase in
instability is expected over southwestern AZ due to the onset of
daytime heating and continued jet-induced divergence aloft will
remain. So while there are some conflicting signals for continued
thunderstorm generation, lingering forcing for ascent should
maintain thunderstorm formation over southwestern to south-central
AZ over at least the next 2-4 hours. Mean steering flow from the
WSW will continue periods of training as some backbuilding
continues to occur, resulting in hourly rainfall of at least 0.5
to 1.0 inches, but idealized training could result in 1-2 inches
in an hour. A few areas of flash flooding are likely to continue,
especially within the near-saturated ground conditions across the
I-8 and I-10 corridors to the SSW of Phoenix.

Otto

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

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

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

LAT...LON   34750934 34160876 33390883 32380957 31781075
            31521189 31641255 32091427 33051418 33751272
            34511103