High Wind in Utah, May 19, 2022

Area Forecast Discussion
National Weather Service Salt Lake City UT
321 AM MDT Thu May 19 2022

.SYNOPSIS...A strong but generally dry cold front will cross Utah
and southwest Wyoming this afternoon through Friday morning,
bringing unseasonably cold temperatures along with some strong and
gusty winds and areas of critical fire weather conditions.
The area will see a steady warming trend this weekend, but conditions
will remain unsettled over northern Utah as southern Utah stays
dry.

&&

.SHORT TERM (Through 12Z/6AM Saturday)...Utah and southwest
Wyoming are under a mild westerly flow this morning ahead of a
storm system currently moving over the Pacific Northwest. This
system will bring a fairly potent front accompanied by some quite
unseasonably cold air into northern Utah later today and through
the rest of the forecast area through Friday morning. Behind the
front, anticipating overnight lows to drop into hard freeze
territory down to northern Utah mountain valleys, and perhaps in
some colder valleys like the Cache as well. Highs Friday should
average 15F below normal for this time of year, struggling to
reach 60F along the Wasatch Front.

With a strong pressure gradient accompanying the front, winds
should become quite gusty. Winds ahead of the front will result in
critical fire weather conditions for areas in southern Utah where
fuels are currently dry. See the fire weather section of the AFD
for more details. Strongest winds are anticipated in the vicinity
of the 120 kt jet, over southwest Wyoming and the Uinta Basin
where there should be some gusts to around 60 mph and a High Wind
Warning is in effect. Gusty winds will also bring some impacts to
Castle Country and northern portions of Utah county, though winds
should not be quite as strong. Weighed adding the San Rafael
Swell and west central/southwest Utah to the Wind Advisory, but
though some areas will see gusts in excess of 40 mph do not
believe the duration of these winds will be enough to warrant a
headline. Winds will tend to taper off this evening behind the
front, but will likely remain gusty overnight over far southern
Utah.

While the winds and drop in temperatures will both be impressive
with this system, associated precipitation looks unremarkable as
the unseasonably cold origins of the system also seem to make it
more than a bit moisture starved. Still, anticipating some showers
over northern Utah and southwest Wyoming this afternoon and this
evening, primarily over the higher terrain with light
accumulations. After a lull tonight into tomorrow morning, should
see northern Utah precipitation increase in coverage, particularly
over the terrain, with the upper trough lingering. Overall
dynamics, at least for the higher terrain, actually look a bit
better at this point than with the initial passage of the front.
Activity will tend to diminish after sunset.

.LONG TERM (After 12Z/6AM Saturday)...While the longwave trough and
its associated bowling ball of cold air will remain in place
Saturday, increasing warm advection along with the breaking up of
cloud cover will allow surface temps to rebound some. Daytime highs
are still expected to run 10-15F below normal across much of the
forecast area. This will kick off a slow warming trend, with
temperatures finally approaching seasonal normals by mid next
week.

While the upper level trough begins to lift and shift east by Sunday
morning, a trailing shortwave is expected to develop northwest of
the forecast area. By Sunday evening, this feature will increase
cloud cover and begin to generate some mountain rain/snow showers.
Conditions will likely be quite breezy across much of the northern
half of Utah and southwest Wyoming early Sunday evening and Monday
as a result. Not expecting an impressive event or rain/snow
accumulations with this feature as it will clear the forecast area
quickly and carries unimpressive dynamics and little moisture to
work with. It will, however, limit much of any additional warming on
Monday.

Ensemble members supporting the development of yet another trailing
shortwave to impact the area Tuesday are becoming scarce, with
cluster analysis with just 22% of the membership in favor. With run-
over-run trends towards an increasingly strong ridge building in by
mid-week, have heightened confidence in and choosing to favor its
earlier arrival and lack of troughing Tuesday in this morning's
forecast package.

&&

.AVIATION...KSLC...VFR conditions will persist throughout
the TAF period. Expecting the arrival of the a potent cold front
around 22Z, and while there is some uncertainty in its strength upon
arrival at the airfield, expecting peak gusts in the low 30 kts out
of the NW. As the pre-frontal setup should favor a northerly flow,
will likely avoid a hard wind shift or noteworthy low-level shear.
CIGs should fall to around 10kft with limited development of cloud
cover between 5-7kft. Precipitation and visibility reductions are
not expected. Winds will remain out of the north overnight into
Friday morning.

REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions will prevail
throughout the forecast area through this TAF period. Far northern
Utah and southwest Wyoming could see brief reductions to MVFR with
the development of low CIGs along the leading edge of the front this
afternoon. Little convective potential accompanies this system
outside of the northern quarter of the forecast area where isolated
storms are possible. Winds will be of concern area-wide, with
widespread gusts in excess of 50 kts possible, with gusts strongest
on the eastern periphery of the forecast area, then in southwestern
Utah in the late evening.

&&

.FIRE WEATHER...A strong cold front will cross the district today,
moving across northern Utah this afternoon and through the
remainder of Utah through Friday morning. Though some showers are
anticipated over northern Utah this afternoon into this evening,
the front will be mostly dry. Of greater impact will be the winds,
becoming quite gusty for areas ahead of the front this afternoon.
The combination of gusty winds and dry conditions will result in
critical fire weather conditions across parts of southern Utah
where fuels are currently dry. Winds will decrease for most areas
by Friday but will remain strong enough over far southwest Utah
for another day of critical fire weather conditions. Temperatures
will cool quite noticeably behind the front, with high
temperatures expected to drop 25-30F, resulting in maxes up 15F
below seasonal normals. Steady warming is expected over the
weekend, bringing high temperatures back to or above normal for
this time of year by Sunday. With the trough lingering over the
area, additional showers are possible for northern Utah, primarily
over the higher terrain, both Friday afternoon and Saturday
afternoon.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Wind Advisory from 4 PM this afternoon to 11 PM MDT this evening
     for UTZ106.

     Red Flag Warning from noon today to 10 PM MDT this evening for
     UTZ489-496-498.

     Red Flag Warning from noon today to 9 PM MDT Friday for UTZ497.

     High Wind Warning from 9 AM this morning to 8 PM MDT this
     evening for UTZ114.

     Hard Freeze Warning from 3 AM to 9 AM MDT Friday for UTZ108-109.

     Hard Freeze Watch from late Friday night through Saturday
     morning for UTZ108-109-118.

     Wind Advisory from noon today to 8 PM MDT this evening for
     UTZ120.

WY...High Wind Warning from 9 AM this morning to 8 PM MDT this
     evening for WYZ021.

&&

SHORT TERM/FIRE WEATHER...Traphagan
LONG TERM/AVIATION...Wessler

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