High Wind in Utah, February 5, 2021

Area Forecast Discussion
National Weather Service Salt Lake City UT
342 PM MST Fri Feb 5 2021

.SYNOPSIS...A storm system embedded within strong northwest flow
aloft will continue to cross the region through tonight. Drier
conditions will follow for the weekend into early next week.

&&

.SHORT TERM (Through 12z Monday)...A progressive short wave
is currently crossing northern portions of the area attm bringing
widespread snowfall to the Wasatch Front and surrounding mtn
areas. The cold pool aloft is rapidly shifting overhead and
sliding southeast across SW Wyoming, but heights are already
building in from the west across the west desert indicative of
the progressiveness and grazing nature of the feature. Snowfall
will remain moderate for the next few hours across the
central/southern Wasatch Front but will then rapidly taper within
a more subsident environment as the trough transitions downstream.
Moderate to strong northwesterly flow will aid some additional
orographic snowfall tonight for prone NW flow producers, but in
large the bulk of additional accums will be occurring over the
next few hours prior to drier air advecting in from the WNW.

Prone downslope areas within strong northwesterly flow have seen
localized strong gusts...downstream of the Raft River Mtns, near
KENV, and western portions of the Uinta Basin, but have namely
remained below advisory levels and within the 35-45 mph range
(peak values occurring now and for the next few hours prior to
decoupling overnight). Stronger gusts are expected to develop
across Castle Country moving forward this evening and overnight,
with H7 speeds near 50kt becoming increasingly capped providing
potential for breaking wave formation downstream of the Wasatch
Plateau, but highest gusts should remain primarily west of SR 10.
Solid Wind Advisory criteria remains forecast, and this headline
will go in effect at 6pm for the overnight hours.

A drier northwesterly flow will set up in wake of today's trough
passage for the upcoming weekend. Clearing and drying expected
most areas, through the Bear River range will remain close enough
to the additional short wave activity rippling across the northern
Rockies for a slight potential for snow showers through Saturday
night.

.LONG TERM (After 12Z Monday)...In between a ridge off the Pacific
coast and a broad trough centered over south central Canada, Utah
and southwest Wyoming are expected to remain under a northwest flow
aloft throughout the long term period. On the plus side, the flow
should be strong enough to limit the development of valley
inversions. However, this pattern also blocks any significant storm
systems from reaching the area so conditions will be mostly dry.

The Canadian trough will stay put over the same general area but
will wobble around enough to occasionally move weak boundaries into
primarily northern Utah that will keep temperatures at or below
seasonal normals for much of the area. There may be enough moisture
in association with these boundaries to produce occasional light
precipitation, primarily for the mountains of northern Utah, with
chances generally increasing as day seven approaches. However,
guidance, as one might expect, does not have a particularly good
handle on the movement of the trough and thus the details of the
situation, so ensemble spread is higher than usual so confidence
remains low on the timing and location of any precipitation.

&&

.AVIATION...At the SLC terminal...IFR conditions in snow are
expected to improve to prevailing VFR by 00Z as snow diminishes.
There is a 20 percent chance of IFR/MVFR conditions persisting into
the early evening. Cigs are expected to rise above 6000 feet AGL
between 03Z and 06Z but there is a 30 percent chance they stick
around longer than expected. A wind shift to the northwest is
anticipated by 00Z.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Wind Advisory until 5 AM MST Saturday for UTZ012.

     Winter Weather Advisory until 5 AM MST Saturday for UTZ007>009.

WY...None.
&&

SHORT TERM...
LONG TERM...
AVIATION...

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