AWUS01 KWNH 030050

FFGMPD

AZZ000-030550-



Mesoscale Precipitation Discussion 0575

NWS Weather Prediction Center College Park MD

850 PM EDT Wed Jul 02 2025



Areas affected...Parts of west-central into southern Arizona



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



Valid 030050Z - 030550Z



SUMMARY...Clusters of thunderstorms containing rainfall rates up

to 1.5"/hr are expected to continue early tonight and may produce

isolated instances of flash flooding, particularly should storms

converge near the Phoenix metropolitan area.



DISCUSSION...GOES19 IR imagery shows cooling cloudtops associated

with strengthening thunderstorms this evening across parts of

central AZ. This ongoing while an upper low over central CA

continues to funnel a plentiful amount of moisture northward into

the Desert Southwest. SPC's mesoanalysis depicts the region with

widespread PWATs above 1.5"and MLCAPE generally between 1000-2000

J/kg. This environment is sufficient for 1.5"/hr rates that could

overcome the dry complex desert terrain to lead to rapid runoff

and flash flooding. Additionally, mean layer winds remain

relatively light (per the 23z RAP) and around 5-10 kts out of the

south-southwest. This leads to thunderstorms dominantly outflow

dependent, as seem in current radar visuals, but also tied to an

instability gradient extending across southwest AZ in a

northwest-southeast orientation. This is where the strongest

storms are current located in west-central and south-central AZ.



Recent 23z HRRR, while not perfect, has a decent handle on ongoing

convection and depicts the potential for isolated to scattered

1-hrly totals of 1-2" to continue through at least 05z, while also

encroaching upon the Phoenix metro. This area is also highlighted

by RAP guidance as an area of increasing low-level convergence and

MLCAPE by about 02z or so. Given the relatively quick outflow

dominated storm motions, flash flooding coverage is expected to be

isolated.



Snell



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



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



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



LAT...LON   34511202 34221105 33411059 32201100 31601168 

            31531227 31761266 32571286 33151328 33641411 

            34061405 34351343