High Wind in Wyoming, February 26, 2024

Area Forecast Discussion
National Weather Service Salt Lake City UT
355 PM MST Mon Feb 26 2024

.SYNOPSIS...A strong cold front will cross the region tonight into
Tuesday morning bringing much colder temperatures as well as
significant snow for many locations. High pressure will build
into the area for midweek before another strong, cold Pacific
system brings the potential for valley snow and much colder
temperatures to the region Friday into the weekend.

&&

.SHORT TERM (Through 12Z Wednesday)...A cold Pacific Northwest
storm system is approaching the northwestern corner of Utah this
afternoon. Ahead of it, increasing moisture and some favorable jet
support have allowed some showers, valley rain and mountain snow,
to develop across northern Utah. Anticipating these showers to
continue into the early evening, with generally light
accumulations. Have also seen southwest winds pick up over the
area, most notably over northwest Utah where some gusts in excess
of 40 mph have been observed. Going Wind Advisory covers this
threat well.

The potent cold front associated with this system will track into
northwest Utah early this evening, before moving across the
remainder of northern Utah and southwest Wyoming during the late
evening and into the overnight hours. A band of moderate to heavy
snow will develop along this boundary, accompanied by strong winds
and rapidly falling temperatures. Overall trend over the past
several model runs has been toward faster overall movement of the
front and an earlier arrival and thus earlier exit over the state.
Therefore, associated amounts with this band will be on the low
side for northern Utah valleys, primarily in the one to three inch
range, but travel will be very difficult during the passage of the
frontal band.

The front will continue to track across central and southern Utah
during the remainder of the morning, with the front exiting the
area around midday. As the front becomes increasingly removed from
the main system, associated forcing will decrease, so overall
amounts over southern Utah will be less impressive. Additionally,
model runs a few days ago had the idea of the Pacific Northwest
system phasing with another system moving across the Desert
Southwest during this time, but recent guidance has abandoned this
idea, decreasing the amount of available moisture and instability
over southern Utah. With this in mind, snow totals for valleys
across west central and southwest Utah are now expected to be
limited at best, leading to the cancellation of Winter Weather
Advisories for those areas with this package. Additionally, have
adjusted the timing of the Wind Advisory previously issued for
Castle Country, as the earlier timing of the front will bring an
earlier onset and end for the potential of strong, gusty winds
along and directly behind the front.

Behind the strong front, anticipating period of relative
subsidence for part of the morning. However, anticipating
additional developing of showers over northern Utah, primarily
over the higher terrain, mid morning through the afternoon as the
main trough crosses Utah and southwest Wyoming. As the system
exits Tuesday evening, high pressure will follow, bringing a rapid
drying trend and an end to precipitation. Mountain totals still
look significant for northern and central Utah, though northern
mountain totals have been adjusted downward slightly due to the
faster movement of the front. Though this brings some areas out of
Winter Storm Warning criteria for amounts, the strong winds that
will accompany the front should bring impacts worthy of the
headline.

.LONG TERM (After 12Z Wednesday)...Southwest Wyoming and Utah
will have weak transient ridging that will transition to zonal flow
Wednesday. Temperatures will warm as a trough tracks to the east,
but be around 5F cooler than normal.

A longwave trough off the coast of British Columbia will dig into
the PacNW Thursday, which will bring more of a southwest component
to the winds. Warm air advection with dry southwest flow will allow
temperatures to reach around 5-10F warmer than normal. Enhanced
winds are forecast for portions of western Utah. As 700 mb flow is
around 30 knots, efficient mixing should translate to similar gusts.

Models and ensembles are in really good agreement on the synoptic
pattern through Friday and into the weekend. The trough will dig
further south and west Friday, with the axis off the PacNW coast.
This will bring better jet dynamics for enhanced clouds for
southwest Wyoming and northern Utah. Mountain snow is likely for
these locations, with upslope enhancement for some locations with
southwest flow. As the trough digs, stronger warm air advection and
enhanced winds are forecast. Models and ensembles highlight the wind
threat, as values stand out compared to climatology. Winds will be
higher for southern and western portions of Utah, but be enhanced
throughout southwest Wyoming and Utah.

The ECMWF Extreme Forecast Index highlights much of western Utah in
a contour of 0.9 or higher for wind gusts Friday. Any value from 0.8-
1.0 stands out compared to climatology. National Blend of Models
give a high probability, near or at 100%, for wind gusts of Wind
Advisory criteria, or 45 mph at places like Cedar City, Delta, and
Milford. Probabilities are lower further north, but are generally
50% or higher, including the Salt Lake and Tooele valley. For High
Wind Warning criteria of 58 mph or higher, probabilities for much of
west and southwest Utah range from around 60-90%, with much lower
probabilities further north. Temperatures will range from 10-20F
warmer than normal.

Confidence decreases Saturday as the trough axis tracks inland, and
a baroclinc zone slides into northern Utah. For southern portions of
Utah strong winds are forecast. As clouds build in, mixing will be
less efficient, but gusts are likely to be similar to Friday. The
most disagreement is with timing of the boundary, which would bring
better forcing and moisture for mountain snow and valley rain that
would transition to snow. The most likely timing is from later
Saturday morning to Saturday evening. Valley and mountain snow are
likely with the front, with snow showers likely lasting through the
end of the weekend.

&&

.AVIATION...KSLC...VFR conditions will transition to a brief period
of MVFR/IFR as a cold front moves through the terminal ~06Z. Expect
a transition from gusty southwesterly winds to gusty northwesterly
winds behind the front. Expect most snow to subside by 10Z with a
return to VFR conditions for the remainder of the period. Expect
some lingering low clouds and snow in the mountains through the
morning creating mountain obscuration. Winds will remain gusty out
of the northwest throughout day.

.REST OF UTAH AND SOUTHWEST WYOMING...A cold front will move through
the area overnight. It will sweep through from northwest (~04Z) to
southeast (~12Z). A narrow band of snow will accompany the band
across northern and central Utah creating a brief window of IFR/LIFR
conditions. Precipitation will end across valleys by sunrise with
snow showers lingering in the mountains creating mountain
obscuration. Winds will remain gusty out of the northwest most of
the day. Southern Utah will likely maintain VFR conditions.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Wind Advisory until 5 AM MST Tuesday for UTZ101-128-130-131.

     Winter Weather Advisory from 11 PM this evening to 5 PM MST
     Tuesday for UTZ102-105-106-118.

     Winter Weather Advisory from 8 PM this evening to 5 PM MST
     Tuesday for UTZ103-104-107-109.

     Winter Weather Advisory until 5 PM MST Tuesday for UTZ108-125.

     Winter Storm Warning until 5 PM MST Tuesday for UTZ110-112-113.

     Winter Storm Warning until 11 PM MST Tuesday for UTZ111.

     Winter Weather Advisory from 2 AM to 5 PM MST Tuesday for UTZ116.

     Winter Storm Warning until 5 PM MST Tuesday for UTZ117.

     Wind Advisory until 8 AM MST Tuesday for UTZ120.

WY...Winter Storm Warning until 5 PM MST Tuesday for WYZ021.

&&

SHORT TERM...Traphagan
LONG TERM...Wilson
AVIATION...Mahan

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