Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Thu Oct 09 2025 21:01:28

AWUS01 KWNH 092101
FFGMPD
AZZ000-NVZ000-CAZ000-100200-

Mesoscale Precipitation Discussion 1173
NWS Weather Prediction Center College Park MD
501 PM EDT Thu Oct 09 2025

Areas affected...Southern Nevada...Southeast California...

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

Valid 092100Z - 100200Z

SUMMARY...Training showers/thunderstorms capable of .5-.75"/hr and
localized streaks of 1-2" may result in localized flash flooding
over the next few hours.

DISCUSSION...CIRA LPW, VWP obs and RAP analysis, shows surge of
subtropical moisture through the Lower Colorado Valley on 15-20kst
of south to southeasterly confluent flow.  Total PWat values have
increased to over 1.25".  Strong convergence along the tight
moisture gradient has providing a sufficient differential boundary
for isentropic ascent.   Deep layer profiles are not particularly
unstable (100-250 J/kg of CAPE) given the mid-level warming, but
the strength of deep layer moisture convergence generally
coincident with a combined diffluent portion of the polar and
subtropical jet noted in GOES-W WV suite was sufficient to allow
for elevated convective cores to develop, maintain and even expand
upstream toward the San Bernadino Range.   Total Pwats of 1.25"
and moistening of the sub-cloud is allowing for some increased
rainfall rates of .5-.75"/hr.=20

Upstream shortwave energy rounding th western edge of the
sub-tropical ridge shows some additional cumuliform mid-level
clouds indicative of upstream energy and potential for further
upstream redevelopment/back-building environment. As such, with
deep layer steering generally oriented parallel to the ascent
boundary there is increasing potential for repeating cores and  a
streak or two of 1-2" totals.  Limited soil conditions and low FFG
values of .75-1.25"/3hrs suggests localized flash flooding is
possible within this band for the next few hours.

Gallina

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!-TjeaugyAH17AL9diwgM5BcLIY8OnJF-Axeu_Gq9oefrHLEt_4bexssdL27yk5C-UbTB=
LLkVtwYYZibVHg6AJcdJ3sI$  for graphic product...

ATTN...WFO...SGX...VEF...

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

LAT...LON   37971501 37571416 36171431 34711595 34491710=20
            35291750 37001667=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to
https://lists.illinois.edu and use the "Unsubscribe" link.  Otherwise email
Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
 * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

.