754
FXUS65 KSLC 262244
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
344 PM MST Tue Nov 26 2024

.SYNOPSIS...A band of moderate to heavy precipitation bringing
valley rain/snow and mountain snow will shift southward through
the evening hours, bringing one last period of snow accumulations
to the mountainous terrain and high elevation valley areas. Colder
air spills into the forecast area overnight, transitioning into a
slow warming trend with dry conditions being maintained through
at least early next week.

&&

.SHORT TERM (Through 12Z/5AM Thursday)...The plume of best
moisture availability and forcing current resides across the
northern Wasatch Front as of 330PM, but trends in radar already
show this feature shifting southward as the incoming frontal
boundary forces the moisture plume southward. As the cold frontal
boundary moves in from the north through the remainder of the
evening, enhanced forcing along the boundary will pair with the
moisture plume and bring a period of heavy precipitation to both
valley and mountain areas. So far, observations of 0.26" of SWE
have been observed in a one hour period in the northern Wasatch
Mountains, and I would expect these precipitation intensities to
be maintained within the band as it progresses south. By 5PM, this
band should shift far enough south to begin impacting the Salt
Lake Valley, Parley`s Canyon, and the Park City area. With the sun
setting around this time and precipitation intensity increasing,
expecting snow levels to crash and bring a period of potentially
impactful snowfall on the I-80 corridor from lower Parley`s
through the UT/WY border, and then south through Heber. For this
reason, have extended the Winter Weather Advisory through 10PM to
account for any potential snow accumulations under the band.

This frontal band should shift through the Salt Lake Valley by
10-11PM, leaving colder temperatures in its wake. The boundary
shifts southward across Utah through the overnight hours, bringing
similar heavy valley rain/snow and higher elevation heavy snow.
The cold temperatures in northern Utah will help to destabilize
the low level environment around the Great Salt Lake and will
likely help to initiate lake enhanced snow showers over Salt Lake
and northern Utah County. Not expecting much in the way of
impacts with these snow showers as they will occur during the
overnight/ early morning hours, but accumulations of up to 1 inch
may be possible for the higher elevation benches. By 7AM, any
lingering snow showers should be tapering off for the bulk of the
morning commute.

Light snow showers may linger in the high terrain of northern Utah
through Wednesday afternoon, however, given the decreasing
moisture profile, not expecting much in the way of additional snow
accumulations/ impacts. Low level cloud cover will be maintained
for the areas near terrain features while broader valley areas/
basins will see gradually clearing skies into the early afternoon.

.LONG TERM (After 12Z/5AM Thursday)...Mean ridge position in wake
of the early week storm will remain upstream with greatest height
anomalies focused over and west of the PacNW. Locally, whilst
residing on the downstream side of the ridge, a dry northwesterly
flow will remain in place across the forecast area through at
least Friday. With this, coupled with a weak short wave passage to
our north late week, temperatures will only moderate subtly each
day, peaking roughly 5F below climo leading into the upcoming
weekend.

By early next week the mean ridge position will begin to shift
inland, encroaching overhead by midweek, with increased subsidence
and building inversion conditions for lower valleys areawide.
Primary forecast problem for the extending revolves around valley
temps within these building inversion conditions, as blended
guidance will likely overestimate daytime highs within such an
environment. For now, have continued to lean on the lower side of
the spread of a warming trend given we`re looking out to the days 5-
7 range, but details will remain challenging until the ridge becomes
more established across the region.

&&

.AVIATION...KSLC...The arrival of the cold front has transitioned
winds to northwesterly, becoming a bit lighter in speed after ~01z.
Winds could be a bit variable until ~06z, when northwesterly winds
around 10kts will kick in once again, likely lasting through the
night. The heaviest rainfall will last until roughly 04z, becoming
more scattered and showery in nature and likely fully transitioning
to snow afterwards. During this period of heavier rainfall, MVFR VIS
and MVFR-IFR CIGs are likely, with CIGs starting to lift after 06z.

.REST OF UTAH AND SOUTHWEST WYOMING...A cold front is currently
making its way southeastward across the area, bringing a
transition to northwesterly winds and a period of heavy rain/snow.
This front will have moved through the Wasatch Front by ~03-04z,
reaching KCDC- KBCE by ~06-07z. MVFR to LIFR conditions are
possible, with the most VIS/CIG reductions in locations receiving
snow (KHCR, KEVW, KBCE). Behind the frontal passage, precipitation
will become more scattered and showery in nature, with periodic
VIS/CIG reductions. Precipitation will largely end across the area
by 15z Wednesday.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Winter Weather Advisory until 10 PM MST this evening for UTZ108.

     Winter Storm Warning until 5 PM MST Wednesday for UTZ110>113-117-
     125.

WY...None.
&&

$$

SHORT TERM...Webber
LONG TERM...Merrill
AVIATION...Cunningham

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