Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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FXUS65 KSLC 211628
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
1028 AM MDT Wed Sep 21 2016

.SYNOPSIS...A strong cold and wet storm system will impact most
of the region through the end of the week.

&&

.DISCUSSION...Tropical moisture is being drawn northward into the
forecast area this morning ahead of an approaching storm system.
Seeing widespread PWs in excess of 1.0 inch across southern utah
with values more in the 0.7-0.8 inch range across northern Utah
and southwest Wyoming. This abundance of moisture has combined
over shortwave energy moving across southern Utah to produce a
broad area of showers. This area of showers will become more
scattered in nature later this morning/early this afternoon as the
wave lifts northward. Have adjusted POPs, sky, and max temps over
primarily southern Utah to account for the persistence of this
feature.

Looking for scattered showers/thunderstorms to develop later this
afternoon with daytime heating. Dynamics in the environment ahead
of the trough will be good with some decent shear. Combined with
the moist airmass, some organized convection is possible with
gusty winds as the primary threat. With the very moist airmass
over southern Utah, storms have a larger possibility of producing
heavy rainfall, despite relatively quick storm motions.

Initial cold front is progged to push into northwest Utah early
this evening before stalling. This boundary will act as a focus
for precip over that part of the state. The front finally gets
moving again Thursday afternoon/evening as the main trough moves
in. Ahead of the system, precipitation will become increasingly
widespread Wednesday night/Thursday with increasing instability in
a moist airmass. Best coverage during the day Thursday should be
on the front end of the jet over central Utah. Snow levels will be
initially quite high today and tomorrow, 10k to 12k feet, but will
drop quickly as the main trough moves in Thursday evening, around
7500 to 8k feet by Friday afternoon. Precipitation should continue
to be fairly widespread across the state through Thursday night
before the focus shifts to northern Utah for Friday.

&&

.AVIATION...VFR conditions will continue at the SLC terminal
through the afternoon with cigs above 6000 ft AGL. Rain showers
are expected to bring cigs to or below that value by early
evening. Southerly winds are expected to remain gusty through the
afternoon.

&&

.FIRE WEATHER...Yesterday`s ERC values were below the 50th percentile near
Arizona, while many stations across central and northeast Utah
were in the 80th to 89th percentile.

Pool of deep moisture will continue to be pulled north across the
area ahead of a cold storm system along the Pacific Northwest
Coast yielding copious showers and thunderstorms. This storm will
make use of the deep moisture and provide plenty of rainfall late
Wednesday into Saturday. Snow Levels are likely to fall to near
7kft by Friday.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...None.
WY...None.
&&

$$

Traphagan/Rogowski

For more information from NOAA`s National Weather Service visit...
http://weather.gov/saltlakecity

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



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