Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 141613
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
1013 AM MDT Mon Aug 14 2017

.SYNOPSIS...A cold front will push south into central Utah tonight
then stall on Tuesday. A warming trend will follow for the
remainder of the week.

&&

.DISCUSSION...An upper trof is over the nrn Rockies this morning
with a couple of short waves lifting up the east side of it and
one strong wave in the base of the trof moving over nrn CA. Water
vapor imagery shows the nrn CA wave is almost closing off and this
is the feature that is forecast to sweep across the Great Basin
and nrn UT this aftn and tonight.

The short waves ejecting north sent the surface boundary into nrn
UT last night and it remains roughly along a line from nrn Utah
Co thru central Tooele Co. This stalled front is forecast to
retreat a little north today before it gets pushed south again
tonight by the passing nrn CA wave.

Southwest flow ahead of this wave will increase today with surface
winds becoming gusty south of the stalled front. PW imagery shows
the column has dried across the CWA from yesterday but there is
abundant low level moisture in place evidenced by surface
dewpoints in the 50s across the south and east. This should mix
out for the most part across the west but some terrain based
convection could develop over the mtns and persist as it moves
off into the ern valleys where somewhat deeper moisture is
pooled. Latest hi res guidance supports this idea.

The more closed nature of the upstream wave would imply a delay to
the frontal push and associated band of precip crossing nrn UT but
still expect at least scattered precip eventually filling in across
the north overnight.

The boundary stalls again across central UT on Tue and could
become a focus for convection in the aftn. In addition, the
upstream wave is now forecast to leave behind a weak trof over the
wrn Great Basin that keeps a threat of convection going over the
CWA into Thu.

Updated earlier to add pops to the central mtns and ern valleys
for this aftn, and made some adjustments to winds.

&&

.AVIATION...Northwest winds at the SLC terminal are expected to
continue through the day. Winds will become gusty after 23-00z as
the main cold front moves through.

&&

.FIRE WEATHER...Warm with a drying today ahead of a cold front
stalled across northern Utah, which will push into central Utah
by tomorrow morning before stalling again and weakening. Winds
will increase this afternoon south of the front with falling RH
across the southwest valleys. Critical fire weather conditions are
expected in these areas and the Red Flag Warning remains in
effect for Fire Weather Zone 497 where fuels are deemed critical.
There is a possibility that the considerable low level moisture
present in these areas this morning may not mix out as fast as
forecast and RH may not reach critical values this afternoon.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Red Flag Warning from noon today to 8 PM MDT this evening for
     UTZ497.

WY...None.
&&

$$

Wilensky/Carr/Lukinbeal

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For frequently asked questions about the Area Forecast Discussion
visit...
http://weather.gov/saltlakecity/general/afd_faqs.php


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