Mesoscale Precipitation Discussion 0686
NWS Weather Prediction Center College Park MD
909 PM EDT Sun Jul 21 2024

Areas affected...Far Southern Arizona...Bootheel of Southwest
NM...

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

Valid 220110Z - 220415Z

SUMMARY...A few more hours of potential 1-2" totals and localized
flash flooding.

DISCUSSION...Multiple strong outflows are starting to result in
faster southward cell motions, particularly further west across W
Maricopa county.  Still, ample deep moisture is present with
1.75"+ total PWats from the Sonoran Desert across S Pima county
back to as much as 1.5" even at higher elevations across Cochise
county, AZ and SW Hildalgo county in NM.  Strong moisture
convergence from 30-50kt low level outflow will rapidly ascend
this moist/unstable air for intense downdrafts after the lead
severe winds, though cooler more dense outflow is likely needed
for strongest vertical ascent.  Given this updraft strength
vertical moisture flux may support instantaneous rates over 3"/hr
but totals of 1-2" given 15-45 minutes of duration may result in
localized flash flooding.

Still, RADAR and Visible/EIR GOES-E loops, indicate cells dotted
across Pima to Santa Cruz along/ahead of the line.  As such,
greatest potential for spots of 2-3" totals exist as these cells
may have time to produce 1-1.5" prior to the arrival of the main
line.  The line is rapidly moving and likely to clear the Old
Mexico boarder by 04z.  As such, localized flash flooding remains
possible through that time.

Gallina

ATTN...WFO...EPZ...PSR...TWC...

ATTN...RFC...CBRFC...WGRFC...NWC...

LAT...LON   33341315 32951270 32681173 32381028 32000883
            31740820 31320816 31250843 31240897 31291028
            31311142 31821280 32131330 32851360 33271346