442
FXUS65 KSLC 162335
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
435 PM MST Tue Dec 16 2025

.KEY MESSAGES...

- Strong westerly winds develop early Wednesday across northern
  Utah and southwest Wyoming, peaking with a frontal passage in
  the afternoon. Strongest winds in excess of 60 mph are expected
  across northwest Utah and Uinta County, WY.

- Expect valley rain and high elevation snow on Wednesday,
  associated with increased moisture from an atmospheric river.

- Another warm storm brings increased winds and another shot of
  rain and high elevation snow to northern Utah Friday into
  Saturday.

&&

.SHORT TERM (Through 12Z/5AM Friday)...GOES-West mid-level
satellite imagery from this afternoon depicts a robust stream of
Pacific moisture originating around Hawaii, also known as an
atmospheric river. This imagery shows the associated moisture and
increased cloud cover beginning to move into northern Utah this
afternoon.

A strong upper-level jet associated with this atmospheric river
is expected to shift inland into northern Utah and southwest
Wyoming early Wednesday before peaking at an impressive 150-170
kts at 250 mb over northern Utah Wednesday afternoon. Strong
westerly winds are expected to develop first across the high
terrain, southwest Wyoming, and far northwest Utah early Wednesday
morning before mixing down to lower valleys of northern Utah
through the late morning. Maximum winds are expected ahead and
along of a frontal boundary moving through the region late morning
into the early afternoon, with gusts 40 to 55 mph for most
northern Utah valleys, gusts in excess of 60 mph across southwest
Wyoming and areas near Curlew Junction and Wendover, and gusts in
excess of 80 mph on mountain ridgelines. Given 700 mb winds
peaking around 50-55 kts Wednesday afternoon, can`t rule out some
wind- prone high ridgelines seeing a period of gusts over 100
mph. Given the widespread nature of these strong winds, wind
headlines are in place for most of northern Utah and southwest
Wyoming on Wednesday. Take the time now to secure any outdoor
holiday decorations or other loose items that may be blown around
in strong winds.

Dry conditions will linger through the remainder of today, before
the strong upper- level jet shifts into a more favorable position
for precipitation to overspread northern Utah and southwest
Wyoming early Wednesday. Conditions will be mainly showery early
Wednesday before a cold front passage early in the afternoon
quickly sweeps a more organized band of heavier precipitation
through northern Utah and southwest Wyoming. This band will move
through quickly from north to south given strong flow aloft, with
main impact between roughly 1 to 5 PM before quickly tapering off
through the remainder of the evening as drier northerly flow
develops behind the front. Snow levels are expected to gradually
increase from 7500-8000 feet early Wednesday up to around 9000
feet just ahead of the frontal passage in the early afternoon. As
such, snow totals through this storm will be heavily dependent on
elevation. Another factor that may impact storm total snow is the
strong winds aloft -- these winds will likely be strong enough to
support an unblocked upslope flow regime that will favor highest
snow totals just along and on the lee side of mountain crests.
Current forecast holds between 2-8 inches of snow for most
northern Utah mountains above 9000 feet. Snow character will be
dense throughout this event due to the warm nature of this system.

Drier conditions settle in late Wednesday, continuing into
Thursday. Slightly cooler temperatures are expected Thursday,
though will generally remain around 10-15 degrees above normal.

.LONG TERM (After 12Z/5AM Friday), Issued 325 AM MST...
Another atmospheric river event
will track into the PacNW Thursday. Through much of Friday,
southwest Wyoming and Utah will be between the exiting and
incoming storm systems. Upslope orographics and weak forcing will
allow for northern mountain snow showers above 7000 feet much of
Friday. Also between systems, similar to Wednesday ahead of that
atmospheric river, winds will be enhanced. South the southwest
winds will be maximized on northern mountain ridgelines and
throughout southwest Wyoming.

There is good agreement with models and ensembles that the jet
associated with abundant moisture advection will slide southward
through Friday, with increasing moisture advection and better
forcing pushing into southwest Wyoming and northern Utah Friday
into Saturday. Snow levels will start around 7000 feet near the
Idaho border and 8000 feet for the Cottonwoods. Snow levels will
increase and decrease some, but stay consistent through the event,
as the main forcing will be the zonal jet. This will transport
abundant moisture, bringing moderate to heavy mountain snow. Snow
ratios will be low through the event, ranging from 5-10:1 for the
northern mountains, with the greatest ratios for the Bear River
Range. Water content will generally range from 0.5-1.0" for the
western Uinta Mountains and Cottonwoods, with 0.75-1.5" for the
Bear River Range. There will be a big range of snowfall totals,
with totals likely exceeding 1 foot for ridgelines near the Idaho
border. There will be a decreasing trend from north to south.

Moisture advection will diminish later Saturday as the forcing
and moisture lift out of the region, but valley rain and mountain
snow showers will continue for southwest Wyoming and northern
Utah. Temperatures from Friday into next week will be warmer than
normal, with valley highs in the 50s for most locations.

For the end of the weekend into next week, there is good
agreement on another atmospheric river event into the western U.S.
Models generally have the track of this storm system more
southward from the previous. There would be enhanced southwest
flow ahead of it, with the better moisture surge north and west of
Utah. The track would lead to more downslope orographics to the
west from the Sierra Nevada Mountains, so a significant mountain
snow event is not anticipated through the start of the week.

&&

.AVIATION...KSLC...VFR conditions are expected at the
terminal through at least late morning, with cigs likely lowering to
or just below 6kft agl between 12-14z. Northerly winds will switch
to diurnal southeasterlies around 03z, becoming gusty after 12z.

REST OF UTAH AND SOUTHWEST WYOMING...Winds for northerly terminals
will be diminishing this evening, becoming gusty and erratic with
incoming showers moving southeasterly from LGU beginning around 11z.
Typical diurnal light winds and clear skies are expected at southern
terminals through late morning.

&& &&

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...High Wind Warning from 8 AM to 5 PM MST Wednesday for UTZ101.

     Wind Advisory from 11 AM to 5 PM MST Wednesday for UTZ102>105-
     107-109-110.

     Wind Advisory from 11 AM to 11 PM MST Wednesday for UTZ114.

WY...High Wind Warning from 8 AM to 8 PM MST Wednesday for WYZ021.

&&

$$

SHORT TERM...Whitlam
LONG TERM...Wilson
AVIATION...Verzella

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