Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Fri Aug 09 2024 19:23:35

AWUS01 KWNH 091923
FFGMPD
COZ000-AZZ000-UTZ000-100120-

Mesoscale Precipitation Discussion 0850
NWS Weather Prediction Center College Park MD
322 PM EDT Fri Aug 09 2024

Areas affected...northern AZ into UT and central CO

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

Valid 091921Z - 100120Z

SUMMARY...Isolated to scattered areas of flash flooding will be
possible across portions of UT, northern AZ into central CO
through this evening. Rainfall rates of 1 to 2 inches in 30-60
minutes are likely to occur in the stronger thunderstorms that
develop.

DISCUSSION...GOES West visible imagery across the western U.S. at
19Z showed the early development of diurnal monsoon convection
across northern AZ into the Wasatch of UT and eastward into CO.
Earlier cloud cover has been eroding, allowing better solar
insolation and CAPE production. Precipitable water values are
similar to or slightly higher than yesterday at this time,
corresponding to standardized anomalies of +1 to +2. Water vapor
imagery showed AZ positioned within a break in the ridge, with the
main belt of westerlies located over the northern Great Basin.
Winds on the 12Z FGZ sounding were generally 10 kt or less from
250 mb to the surface, resulting in 850-200 mb layer mean flow of
just 3 kt. Deeper layer mean flow increases into central UT to
near 10 kt and 15+ kt in central CO.

Due to the anomalous moisture in place and expectation for
increasing instability through 00Z (MLCAPE was less than 500 J/kg
area-wide via the 18Z SPC mesoanalysis), thunderstorms will become
more numerous through the remainder of the afternoon into the
evening hours. While 700 mb winds are weak, there is some
confluent flow noted over southern UT into CO which help to focus
thunderstorms as convective initiation progresses. Outflow
boundary influences will come into play later in the day, driving
storm behavior but some brief training will be possible from UT
into western CO where mean westerly winds could support higher
rates where cell alignment sets up in accord with the mean wind.
Slow moving and training storms over the region will pose a risk
for high rainfall rates of 1-2 inches within 30-60 minutes,
whether due to slow movement or brief training. Isolated to
scattered areas of flash flooding will be possible.

Otto

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!62oCx3NiAXpj0wQ8a9vf0m2hiwmuwO4Kxl-OAE67G0MrtoHbdqWZILk9hnaRLO7XeW6K=
JadlkMHiUifsU24_Bk7ZRlY$  for graphic product...

ATTN...WFO...BOU...FGZ...GJT...PUB...SLC...VEF...

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

LAT...LON   40260794 40190673 40140602 40140568 39880538=20
            39550544 39300586 39080614 38870624 38650645=20
            38190693 37580740 37370792 37280840 37040916=20
            36611009 35541114 35231154 35011194 35051265=20
            35321341 35641376 36081396 36691398 37211381=20
            37661364 38261318 38491298 38731265 39041226=20
            39181206 39531172 39781100 39901055 40070976=20
=20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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