AWUS01 KWNH 042108

FFGMPD

NMZ000-AZZ000-050240-



Mesoscale Precipitation Discussion 0939

NWS Weather Prediction Center College Park MD

507 PM EDT Tue Aug 04 2026



Areas affected...southwestern NM into southeastern/southern AZ



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



Valid 042106Z - 050240Z



Summary...Increasing thunderstorm coverage across southwestern NM

into southeastern AZ through the evening and early overnight may

result in a few areas of flash flooding. Hourly rainfall totals of

1-2 inches and sub-hourly rains of 0.5 to 1.0 inches in 15-30

minutes are expected through 03Z.



Discussion...2045Z visible satellite imagery showed monsoonal

convection underway across the higher terrain of southwestern NM

into southeastern AZ. Water vapor imagery showed the center of a

west-east elongated mid to upper-level ridge over south-central AZ

into NM, with deeper layer mean flow from the E to ENE across the

south-central AZ/NM border into northern MX. PW values across

western NM into eastern AZ were average to slightly above average

for this time of year (per blended TPW imagery) and mostly clear

skies through the mid-afternoon have contributed to 500 to 1500+

J/kg MLCAPE across southeastern AZ into far southwestern NM via

20Z SPC mesoanalysis data, with higher instability in excess of

2000 J/kg with southward extent into northern MX.



Expectations are for thunderstorms to continue forming along the

higher terrain of southwestern NM into eastern AZ over the next

few hours, with an eventual movement toward the west and southwest

into the lower deserts and eventually portions of the I-10 and

I-19 corridors which have greater instability. While some slow

cell movement may be observed early on in the storm life cycle,

individual cell speeds of 10 to 20 kt are expected as one nears

the US/MX border due to the presence of 20-35 kt of easterly 500

mb winds over southern AZ into northern MX on the south side of

the ridge axis. Rainfall rate potential will be for 1 to 2 inches

in an hour but also high sub-hourly totals of 0.5 to 1 inch in

15-30 minutes.



Thunderstorm coverage is also expected to increase through 00Z

across the mountains of southeastern AZ into northern MX (per

recent HRRR/RRFS runs), with these cells generally moving from

east to west. Outflow development within the dry sub-cloud layer

should contribute to eventual merging and clustering of cells with

movement toward the west. As this occurs, locally enhanced rain

rates of 1-2 inches per hour are expected but with much of the

heaviest rain falling in the sub-hourly time frame. These intense

rainfall rates may produce a few areas of flash flooding through

03Z.



Otto



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



ATTN...WFO...ABQ...EPZ...FGZ...PSR...TWC...



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



LAT...LON   34671088 34440963 33560823 32640746 31850739 

            31510796 31110837 31071013 31121107 31481175 

            32271168 32891146 33881154