Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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FXUS65 KSLC 190341
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
841 PM MST Wed Jan 18 2017

.SYNOPSIS...High pressure over the Great Basin will give way to a
series of weather disturbances beginning Thursday and lasting
into next week.

&&

.DISCUSSION...The upper ridge axis has shifted over ern UT this
eve and high clouds have thickened up across the CWA west of the
axis obscuring the stratus deck still in place across the
northwest deserts. Radar shows some snow has already spread into
the far nwrn CWA.

The southwestern valleys broke out this aftn while the nw deserts
stayed cold under the stratus deck. Delta in Millard Co is about
the dividing line. Currently the valleys north of there have
chilled back down into the lower 20s and it is probable we will
not mix out before precip starts tomorrow morning leading to a
potentially snowy commute along portions of the Wasatch Front.
However, precip intensity may not be all that great in the Salt
Lake valley due to the southerly flow just above the inversion.

Of note is that a few sites around 5500 to 6000 feet along the
upper benches are in the upper 30s now but they are also very dry
so evaporative cooling will likely keep precip snow as it falls
thru this warmer layer.

The current distribution of advisories correctly highlights the
snow threat for nwrn valleys and it may need to be expanded into
the Wasatch Front if accumulating snow does indeed develop farther
east.

Precip should fall as rain or melting snow in the swrn valleys
until late tomorrow when colder air arrives.

It is also possible there could be enough impact in the nrn mtns
in the morning to warrant expanding the mtn advisories north.
Current forecasts do have high pops for snow already in these
areas for the morning, so will hold off on changes to highlights
at this time to allow a full suite of the latest guidance to
arrive.

The focus of precip should shift swd by the end of the day
tomorrow and it should taper off in all areas by Fri morning. The
next trof starts to spread precip back into swrn UT Fri aftn,
spreading north overnight into Sat but the greatest amounts look
to stay over the south.

No updates planned at this time.

&&

.AVIATION...MVFR vsbys are expected to prevail at the SLC terminal
through the evening lifting to VFR as winds shift to southeasterly
around 05z. IFR in snow will develop between 13-15z tomorrow
morning.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Winter Weather Advisory from 2 AM Thursday to 5 AM MST Friday
     for UTZ010-015-517-518.

     Winter Weather Advisory from 2 AM to 11 PM MST Thursday for
     UTZ005.

WY...None.
&&

$$

Wilensky

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visit...
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