AWUS01 KWNH 030620

FFGMPD

AZZ000-NVZ000-CAZ000-031130-



Mesoscale Precipitation Discussion 0576

NWS Weather Prediction Center College Park MD

218 AM EDT Thu Jul 03 2025



Areas affected...northwestern AZ, southern NV into eastern CA



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



Valid 030617Z - 031130Z



SUMMARY...Isolated to widely scattered instances of flash flooding

will be possible across portions of northwestern AZ, southern NV

into eastern CA through 11Z. High rainfall rates of 0.5 to 1.0

inches in 15 minutes will be possible with storm totals near 2

inches.



DISCUSSION...Area radar and GOES West infrared satellite imagery

showed an increasing trend in convection over northwestern AZ,

centered over central and southern Mohave County through 06Z. Low

level confluence and low level moisture increasing from a

combination of remnant outflow from the east and low level winds

advecting in moisture from the south to southeast have allowed for

an increase in MLCAPE over western/northwestern AZ with 06Z SPC

mesoanalysis data showing 1000 to 2000+ J/kg. The SSE to NNW

oriented instability max was co-located with anomalous moisture

with SPC mesoanalysis estimated PW values of 1.5 inches along the

CA/AZ border to 1.8 inches near PHX.



Continued development of convection is expected over northwestern

AZ, southern NV and eastern CA as low level moisture increases

instability to the west and slightly north over the tri-state

region over the next few hours. Aloft, the region resides to the

east of an upper level trough over south-central CA with a 50-60

kt jet max measured by GOES West DMV over eastern NV, placing

locations over the tri-state region within the favored

right-entrance region for ascent. Mean steering flow from the

south to southwest at 10-20 kt should keep individual cells moving

but upstream development could allow for brief training with high

rainfall rates of 0.5 to 1.0 inches in 15 minutes, with similar

rates observed earlier in the night to the west of the Phoenix

metro. Any instances of flash flooding over southern Nevada,

northwestern AZ and eastern CA should be isolated to widely

scattered in coverage and storm total rainfall is expected to max

out near 2 inches.



Otto



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



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



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



LAT...LON   37331563 37161428 36151322 34351332 33701460 

            34101540 35471630 36721641