High Wind in Wyoming, April 4 to 5, 2022

Area Forecast Discussion
National Weather Service Salt Lake City UT
944 AM MDT Mon Apr 4 2022

.UPDATE...Very windy conditions remain in the forecast tonight
across much of northern Utah and southwest Wyoming. There have
been some updates to the timing of when winds will peak and we
have increased winds and wind gusts particularly over downslope
areas of the Bear River Range and across southwest Wyoming. A Wind
Advisory has been added to the hazard headlines for the Bear River
Valley starting at 6 pm MDT this evening and continuing through 6
PM Tuesday. There are currently no other changes to the headlines.
Winds are expected to peak in speed along the Wasatch Front
around midnight.

&&

.SYNOPSIS...Winds will increase over the area, particular northern
Utah and southwest Wyoming, this afternoon with the arrival of a
storm system. Strong gusty winds along with some mountain snow
will continue through Tuesday. High pressure will return by
Wednesday.

&&

.SHORT TERM (Through 12Z Wednesday)...Seeing mostly clear skies
and seasonable temperatures this morning over the majority of
Utah and southwest Wyoming this morning but change is on the way
in the form of an approaching storm system. This system is
currently moving onshore along the Pacific Northwest coast and is
on track to graze northern Utah and southwest Wyoming late today
through Tuesday. Biggest story with this system is the wind, as
the trough will be accompanied by a potent 150 knot jet as it
moves through. Biggest impacts will be over southwest Wyoming and
the Uinta Basin where some gusts in excess of 60 mph will be
possible Monday afternoon into Tuesday. The mountains of northern
and central Utah will also see some significant gusts.

Given the grazing nature of the system that keeps the best
dynamics north of the area and the warm airmass out ahead of the
system, impacts from snow will be a bit limited and confined to
northern Utah. Looks like best accumulations will be late
Monday/early Tuesday and the trajectory of the system gives the
western Uinta mountains the best shot of significant snow. With
this in mind, have replaced the Wind Advisory for that zone with a
Winter Weather Advisory for snow and wind to highlight the
potential for higher accumulations and blowing snow. Will also
need to monitor trends in the Wasatch Mountains north of I-80,
primarily for areas near the Utah/Idaho border, as there is a
chance for significant accumulations there as well. However, did
not issue a new headline at this time because as of now amounts
look to stay below advisory criteria for the vast majority of the
zone. Otherwise, made no changes to the headlines as what was
issued with the afternoon package covers expected trends well.

By Tuesday morning, coverage of precipitation will tend to trend
downward tapering off during the afternoon for most locations.
With unseasonably cold area continuing to stream in, snow levels
should lower to valley floors during this time but accumulations
will be limited with the brunt of the precip having ended. Threat
of strong gusty winds continues through much of the day, though,
particular in southwest Wyoming and northeast Utah with the nose
of the jet expected to pivot south slightly. Winds should decrease
significantly by Tuesday evening, however, with the system
exiting and the jet weakening.

.LONG TERM (After 12Z Wednesday)...Cool northwesterly flow will
remain in place during the middle of the week as the late Monday/
Tuesday storm system continues to track east of the forecast area.
With high pressure building to the north of the area and lower
pressure to the south and east, a noteworthy pressure gradient will
remain in place and help generate continued breezy conditions,
especially across the southern two-thirds of the area. That said,
winds aloft will not be supportive of generating any lingering high
wind concerns... so not seeing any need for extension of pre-
existing headlines. Gusty conditions can be expected in areas prone
to gap winds and downsloping winds (i.e. Black Ridge Canyon and the
SR-10 corridor through Castle Country), however, winds will relax as
high pressure continues to filter into the area through the evening
and overnight hours into Thursday.

Upstream of the area, a substantial ridge will continue to shift
into the western U.S. which will act to expand high pressure across
the eastern Great Basin and bring consistent daily high temperature
rises across the area. This warming trend will have a bit of a
delayed start as cooler air remains draped across the region on
Wednesday, however, by Thursday ensemble guidance is in solid
agreement of placing the colder air downstream which will allow warm
high pressure to take back control. For northern Utah, near to
slightly above normal temperatures are expected by Thursday and will
become ~10-15 degrees above normal by Friday and Saturday. For
southern Utah, expect temperatures to already be ~5-10 degrees above
normal by Thursday, potentially pushing 20 degrees above normal by
Friday and Saturday.

As we progress more into the weekend, ensemble guidance remains in
good agreement on flattening the ridge and developing a broad
longwave trough over the western U.S. by Sunday. Similar to trends
in guidance yesterday, models are still a bit dispersive in the
overall moisture availability with this next system. As per the Apr
3 12Z ensemble cluster analysis, about 50-60% of ensemble members
place some sort of measurable precipitation over a portion of Utah
and southwest Wyoming by Sunday, whereas the other 40-50% maintain a
dry forecast. Similar trends are reflected in the max temperature
forecasts as ~50-60% of models indicate significant cooling by
Sunday, and the other 40-50% maintain warmer temperatures. Digging a
little deeper, every ensemble EOF cluster shows some sort of trough,
but the major variance looks to be in how quickly this trough
settles over the area. Apr 4 00Z cluster analysis shows a trend
toward drier conditions on Sunday, with more models honing in on
Monday as the wet period... but with similar statistics (e.g. 50/50
wet vs dry). Needless to say, there is still a great deal of
uncertainty, but changes are coming.

&&

.AVIATION...KSLC...southerly drainage flow will continue over
the SLC terminal through the morning hours, becoming gusty around
17Z. A transition to gusty southwest flow is expected around 18Z,
with a west to northwesterly shift in wind expected about earlier
than previously forecast, or between 19Z-20Z. There remains a 40%
chance that winds revert back to southerly flow around 00Z,
otherwise, northerly flow is expected through the evening. Shower
activity will increase after 20Z this afternoon, leading to local
mountain obscuration but still remaining VFR through the evening.
MVFR CIGs possible between 09Z-18Z, and plan to introduce a mix with
snow as well during this time.

Rest of Utah and Southwest Wyoming...VFR conditions are expected to
prevail across the region today under increasingly cloudy skies.
Gusty south to southwesterly winds are expected across most areas
during the late morning and afternoon hours. An area of showers are
expected to develop along terrain north of KSPK after ~19-20Z,
causing widespread mountain obscuration. Shower coverage will begin
influencing valley areas late in the evening, where CIGs may drop to
near MVFR toward the end of the TAF period.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Wind Advisory from 9 AM to 6 PM MDT Tuesday for UTZ120-121.

     High Wind Warning from 3 PM this afternoon to midnight MDT
     Tuesday night for UTZ114.

     Wind Advisory from 6 PM this evening to midnight MDT Tuesday
     night for UTZ117.

     Wind Advisory from 6 PM this evening to 6 PM MDT evening for
     UTZ109.

     Wind Advisory until 6 PM MDT Tuesday for UTZ101-110.

     Winter Weather Advisory from 6 PM this evening to midnight MDT
     Tuesday night for UTZ112.

WY...High Wind Warning from 3 PM this afternoon to midnight MDT
     Tuesday night for WYZ021.

&&

UPDATE...NDeSmet
SHORT TERM...Traphagan
LONG TERM...Webber
AVIATION...Webber/ADeSmet

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