Mesoscale Precipitation Discussion 0588
NWS Weather Prediction Center College Park MD
913 PM EDT Thu Aug 02 2018

Areas affected...Sun Valley/Sonoran Deserts of AZ...

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

Valid 030113Z - 030530Z

SUMMARY...Highly unstable, deep moisture and slow convergent cell
motions support flash flooding threat across Sonoran Desert into
Sun Valley.

DISCUSSION...Temps AoA 105-110F and Tds in the low 60s support,
RAP analysis depicting highly unstable corridor of uncapped 
MLCAPEs reaching 2000-3000 J/kg across the northern and eastern
Sonoran Desert. A broad area of enhanced CU with some TCU across
La Paz county as well as into N Pinal along the NE periphery of
strong but slow moving convective complex just north of I-8 west
of I-10.  This later complex rapidly developed with the help of
the instability and resides within deeper moisture pool with total
PWATs up to 1.75" per 00z soundings and RAP analysis. Suggesting
highly efficient rainfall production for cells developing.  Given
proximity to mean deep layer anticyclone over SE AZ/SW NM...cell
motions are generally weak or suggest a southwesterly component
that would advance toward the Sun Valley with general convergence.
 Rain rates up to 1.75" are possible leading to flash flooding
conditions, though the overall coverage should be scattered.  The
only exception to this may result from converging outflow
boundaries falling off the San Francisco Plateau/Mogollon Rim 
helping to enhance broader pockets of enhanced overturning that
could collapse quickly for a larger area of heavy rainfall
increasing localized flash flooding threat in common drainage
basins.  

Gallina

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

ATTN...RFC...CBRFC...

LAT...LON   34471348 34001263 33711120 33251021 32401052
            32651269 32981348 33621426 34281420