340
FXUS65 KSLC 292238
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
338 PM MST Sat Nov 29 2025

.SYNOPSIS...An approaching early winter storm system will cross
the region late tonight through Sunday. Cooler and stable
conditions will follow for Monday, with another system expected
midweek.

&&

.DISCUSSION...

Key Points:

- Have issued a Winter Weather Advisory for the Northern and
  Central Mountain areas from 5am Sunday to 11pm Sunday Evening.

- An early winter storm system will bring widespread accumulating
  snow to the higher terrain Sunday into Sunday evening.
  Widespread snow accumulations of 4-8 inches of new snow can be
  expected, with locally up to 12 inches in the upper Cottonwoods
  and portions of the Wasatch Plateau. This snowfall coupled with
  a very busy travel Day (Sunday) will make travel difficult over
  the higher passes and canyons Sunday into Sunday evening.

- Light snow accumulations (<3 inches) are likely for portions of
  the northern Wasatch Front and Cache Valley Sunday morning, and
  bench areas in the Salt Lake Valley later Sunday morning into
  the afternoon hours. Minor accumulations (T-1") are possible
  down to the valley floors of the Wasatch Front as precipitation
  transitions to snow during the day Sunday.

Afternoon satellite and H5 analysis indicate a sharpening trough
dropping south-southeast across southern BritCol and just now
translating into the PacNW. Model consensus retains this
trajectory moving forward tonight with passage across the eastern
Great Basin (and locally) during the day Sunday prior to
translating east and downstream of the area Sunday night.

A favorable set up looks to unfold late tonight and especially
Sunday with increasingly broad upper diffluence shifting NW-SE in
advance of the positively tilted wave as it further sharpens over
northern Utah Sunday morning, this driving further development of
favorable left exit jet support over central/northern Utah with
speeds increasing to ~90kts through early afternoon. Broad lift
coupled with modest low/mid level moisture associated with the
trough will drive increasingly widespread light to moderate precip
across the area during the day Sunday, with rates heaviest tied
closest to its axis passage roughly midday in the north, and
afternoon/early evenings central/south. Have noted model details
trending a skosh more bullish regarding H7 thermal packing in
advance of this axis, which will likely aid P-type to transition
to all snow down to the lower valleys later Sunday morning along
the Wasatch Front.

Primarily looking at travel across the higher passes/canyons as
the biggest foreseen impact Sunday, namely in northern/central
Utah where snow totals are expected to be greatest. Although snow
levels are expected to drop to valley floors, a combination of
warm ground temps given ambient temperatures of late, and lower
rates (outside of the mountains) should preclude any lower valley
road accums, though some light accumulations will remain likely on
grassy and (possibly) elevated surfaces. This combined with a very
busy travel day Sunday...opted to issue a Winter Weather Advisory
for the northern/central mountains where those travel impacts
will be highest. See WSW for further details.

Areal extent of snowfall is expected to diminish rapidly with
axis passage later Sunday/Sunday evening for many areas, though
maintenance of of somewhat unstable/moist northwesterly flow does
look to drive a continuation of snow for the favorable orographic
areas along the I-15 corridor and potentially eastern bench areas
from roughly SLC south to CDC. A combination of recent model
nudging towards more lift in advance of the axis, and slightly
more favorable orographic potential post passage, has trended
storm totals up again this forecast.

Heights will rapidly build later Sunday night/Monday in wake of
the trough moving downstream, but given the CAA associated with
passage, looking at maintaining much cooler temps Monday into
Tuesday than experienced this past month. Given the long wave
pattern shifting minimally through late week, with amplified
ridging over the eastern Pacific, and the eastern Great Basin
remaining on the western periphery of broad long wave trough, not
surprised to see additional waves slated to cross the area later
Tuesday and Wednesday, and again later next weekend. Neither
overly impactful, more of the nickel and dime nature and very "La
Nina-ey". Though confident in their future existence, models
continue to have difficultly resolving details in amplitude,
and/or possible western retrogression within the long wave
ridge/trough setup in place. More detail to come in future
forecasts.


&&

.AVIATION...KSLC...Light, northwesterly flow persists through around
03z before clocking to southerly. Conditions begin to deteriorate
tomorrow around 12z with CIGs initially dropping to below 6000ft.
Intermittent snow showers are possible from 12-16z before becoming
prevailing. During this time, MVFR CIGs and perhaps MVFR vsbys will
develop. Wintry precip will taper off from 21-24z, though it remains
somewhat uncertain if the MVFR CIGs will lift by the end of the
period.

.REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions persist across
the forecast area through 09-12z tomorrow. A winter storm will move
into the area bringing widespread snowfall, MVFR CIGs, and perhaps
MVFR vsbys to all sites tomorrow except for our southern UT sites.
Precipitation will begin to taper off following 21z, though it
remains somewhat uncertain if MVFR CIGs will persist through the end
of the TAF period.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Winter Weather Advisory from 5 AM to 11 PM MST Sunday for
     UTZ110>113-117.

WY...None.
&&

$$

Merrill/Worster

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http://weather.gov/saltlakecity