Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Wed Aug 02 2023 18:43:21

AWUS01 KWNH 021843
FFGMPD
WYZ000-UTZ000-IDZ000-030045-

Mesoscale Precipitation Discussion 0838
NWS Weather Prediction Center College Park MD
242 PM EDT Wed Aug 02 2023

Areas affected...Central & Western WY...Eastern ID...Northern UT

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

Valid 021845Z - 030045Z

SUMMARY...Numerous thunderstorms developing throughout the region
may produce as high as 2"/hr rainfall rates this afternoon. The
combination of excessive rainfall rates and overly saturated soils
will likely result in flash flooding.

DISCUSSION...A 500mb vorticity maximum is fostering upper level
divergent flow over the central Rockies this afternoon at the same
time as strong surface based heating is rapidly destabilizing the
atmosphere. RAP mesoanalysis shows MLCAPE has increased 200-600
J/kg over the past 3-hours in southern WY and northern UT. The
biggest factor in today's flash flood threat is the increase in
atmospheric moisture. PWs of 1-1.2" are expected in south-central
WY and eastern ID, where PWs according to NAEFS are above the 97.5
climatological percentile. RAP model soundings in south-central WY
depict exceptionally saturated atmospheric profiles with skinny
CAPE aloft. Mean steering flow remains out of the S-SW and around
10-15 knots. This flow regime should help to keep some storms on a
progressive heading, but this could also favor persistent
back-building convection along topographically-favored terrain.

Latest 12Z HREF shows up to 20-30% probabilities for 1-hr QPF > 1
hr FFGs in parts of western and central WY. These areas of WY are
particularly prone to flash flooding given recent heavy rainfall.
AHPS 7-day rainfall analysis shows up to 400-600% of normal
rainfall for many locations stretching from southeast ID and
northern UT all the way to the Front Range of southern WY. With no
shortage of moisture aloft, surface based heating set to continue
for several more hours, and an upper level disturbance aiding in
vertical ascent to the west, thunderstorms will be capable of
producing up to 1.5"/hr rainfall rates and possibly even as high
as 2"/hr in the most intense cells. Areas most at-risk for flash
flooding are in areas hit hardest by heavy rainfall over the past
week, as well as along rugged terrain and residual burn scars.

Mullinax

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!8MN6t1KQTIwF9fofwl9SMUfR5kxjhLBLHKiyuIMnTAPLXrD0z7wwYAPbKJbTTJ7c82ei=
gQoQ29Zjth22sUSIqKuZeCw$  for graphic product...

ATTN...WFO...CYS...PIH...RIW...SLC...

ATTN...RFC...CBRFC...MBRFC...NWRFC...NWC...

LAT...LON   44740935 44600791 43420642 42830519 41410502=20
            41090609 41170920 41061134 40781256 41921359=20
            43201344 43781213 44221097=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 3.14-Linux
 * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

.