AWUS01 KWNH 191325
FFGMPD
AZZ000-191800-

Mesoscale Precipitation Discussion 1106
NWS Weather Prediction Center College Park MD
923 AM EDT Fri Sep 19 2025

Areas affected...Central AZ

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

Valid 191323Z - 191800Z

SUMMARY...Small bands of locally training showers and
thunderstorms may continue for at least a few more hours.
Additional concerns for some flash flooding will exist this morning.

DISCUSSION...GOES-W IR satellite imagery is showing a couple of
small southwest to northeast oriented bands of heavy showers and
thunderstorms impacting portions of central AZ. The activity is
mainly focused in between Phoenix and Winslow, with some impacts
noted into the southwest-facing flank of the Mogollon Rim.

The convection is embedded within a modestly unstable airmass with
MUCAPE values generally around 500 J/kg, and is aligned with a
corridor of somewhat focused moisture convergence associated with
the low to mid-level southwest flow regime that remains in place.
There is also proximity of left-exit region upper-jet dynamics
associated with the subtropical jet crossing far southern CA and
southern AZ which is generating at least some deeper layer ascent
over the region.

The ongoing convection may tend to linger this morning for at
least a few more hours given the upper-jet support, and there will
be continuing concerns for some smaller scale backbuilding and
training of convective cells. Anomalous moisture remains in place
early this morning, with PWs running near 2 standard deviations
above normal, and this will still help support heavy rainfall
rates that may reach 1 inch/hour with the stronger storms.

Given the cell-training concerns, some additional short-term
amounts of up to 2 inches cannot be ruled out for this morning.
This may result in some additional localized concerns for flash
flooding with impacts primarily to the normally dry washes and
burn scar locations.

Orrison

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

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

LAT...LON   35551100 35191020 34431013 33911083 33571236 
            34031303 34721302 35271219 

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