Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Tue Aug 27 2024 17:40:24

AWUS01 KWNH 271740
FFGMPD
TXZ000-COZ000-NMZ000-AZZ000-272338-

Mesoscale Precipitation Discussion 0934
NWS Weather Prediction Center College Park MD
139 PM EDT Tue Aug 27 2024

Areas affected...Southeast Arizona, New Mexico, far southern
Colorado, and far western Texas

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

Valid 271738Z - 272338Z

Summary...Increasing coverage of slow moving thunderstorms are
expected to impact parts of the Southwest and Southern Rockies
this afternoon. Rainfall rates may reach up to 0.75-1.0" per hour,
with localized totals approaching 1.5-2" by tonight. Isolated
instances of flash flooding are possible, especially in and around
burn scars and highly susceptible terrain.

Discussion...GOES-East satellite imagery shows developing cumulus
over terrain of the Southern Rockies and Southwest, which is
anticipated to build through the afternoon hours as daytime
heating increases lapse rates and promotes scattered thunderstorm
development. This area falls within an area of upper divergence as
an upper low lingers off the coast of southern California and a
larger-scale trough extends from the Northern Plains to the
central Rockies.

Meanwhile, Advected Layered Precipitable Water shows a stream of
elevated upper level moisture content stretching from the southern
AZ-NM border to northwest NM, while PWs of 1-1.4" stretch from
southeast AZ to central/eastern NM per SPC's mesoanalysis. These
PW values peak at +1.5 standard deviation above the climatological
mean and above the 75th percentile across southwest NM per the 00z
GEFS and should help storms contain hourly rainfall rates up to
around 0.75-1.0" per hour, especially near convective initiation
over the higher terrain. Instability in the area on the order of
500-1000 J/kg of MUCAPE will help promote updraft maintenance,
with a gradual advection westward that should lead to later focus
near the southern AZ-NM border. However, weak southerly mean mid
to-upper level winds should lead to chaotic outflow driven
boundaries and storm motions driving storm movements.

12z HREF neighborhood probabilities for at least 1" per hour are
elevated (10-30%) with higher amounts over the Sacramento Mts.
Sensitive terrain with burn scars and dry washes will create
chances for localized flash flooding concerns due to the scattered
convection.

Snell

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!7Ce8YvvHOzsWQu5HZzYhu0i2rsvuc-mb0TYEkh3E-0l_5wYMEPqXbCIcczp-W5TkHHqZ=
qyLmp2pHDmLMtgbqgtBKAJ4$  for graphic product...

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

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

LAT...LON   37240575 37210438 36900354 36290352 35800438=20
            35080477 33880482 32140484 31490607 31200895=20
            31331104 32761129 33971049 35230873 36110750=20
            36810669=20

=3D =3D =3D
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