540
AWUS01 KWNH 302013
FFGMPD
TXZ000-NMZ000-AZZ000-010212-

Mesoscale Precipitation Discussion 0525
NWS Weather Prediction Center College Park MD
412 PM EDT Sun Jun 30 2024

Areas affected...Far West TX...Central and Southern NM...Central
to Southeast AZ

Concerning...Heavy rainfall...Flash flooding likely

Valid 302012Z - 010212Z

SUMMARY...Scattered areas of showers and thunderstorms will be
developing and expanding in coverage once again this afternoon and
evening. Some areas of flash flooding are likely given the
sensitivities involving the normally dry washes and area burn
scars.

DISCUSSION...The midday GOES-E satellite imagery shows convective
initiation taking place once again as monsoonal moisture rounding
the western periphery of the subtropical ridge advances north and
west up across areas of central and western NM through central and
southern AZ. Some areas of southern AZ in particular have some
very high PW anomalies that are in the 95th to 99th percentile of
climatology and the latest CIRA-ALPW data confirms the deep layer
nature of the monsoonal moisture environment.

SBCAPE values are already on the order of 1500 to 2500 J/kg across
areas of south-central NM westward into southeast AZ. And
satellite imagery shows an MCV lurking over far northwest Mexico
just to the south of the AZ border. Around the eastern flank of
this MCV is a corridor of stronger 850/700mb moisture flux
magnitudes impacting far southwest NM and through much of
southeast AZ. The combination of stronger moisture transport
parameters and the moderate to strong surface-based instability
from daytime heating will couple with orographic ascent/upslope
flow to favor increasing coverage of showers and thunderstorms
over the next several hours.

Given the anomalously high PW environment and level of
thermodynamic support, the rainfall rates are expected to again be
quite heavy and capable of reaching 1 to 2 inches/hour. The 12Z
HREF guidance suggests some potential for some loosely organized
bands of convection to eventually evolve, and some of the modest
shear parameters overhead around the western flank of the ridge
axis supports this. There may be some localized training of these
cells given the orientation to the deeper layer steering flow, and
thus some localized storm totals may reach 2 to 4 inches as
convection evolves.

Given the high rainfall rates and sensitivities on the ground with
the normally dry washes and area burn scar locations, additional
areas of flash flooding are likely to occur over the next several
hours.

Orrison

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

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

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

LAT...LON   36161089 35150919 35010773 34650622 33920551
            32810498 31100373 30510434 30820563 31440704
            31290909 31421025 32361103 33661178 34651281
            35891267