232
FXUS65 KSLC 160921
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
321 AM MDT Thu Oct 16 2025

.SYNOPSIS...A low pressure system will maintain unsettled
conditions across northern Utah today while the south trends
drier. A warming and drying trend will follow for the upcoming
weekend. The next storm system will affect the area late Sunday
into early Monday.

&&

.DISCUSSION...

Key Points:

- Widespread valley rain/mountain snow will continue across much
  of northern Utah and southwest Wyoming this morning, with
  accumulating snow above 6000 feet.

- Cold temperatures tonight will result in freezing temperatures
  in the western Uinta Basin, Castle County, and west central Utah
  near Delta.

- Patchy fog is possible late tonight through Friday morning
  within sheltered northern valleys including the Cache and Bear
  River Valleys.

- Roughly 80% of ensemble members show potential for another cool
  Pacific system to impact the region late Sunday through early
  Monday.

An upper low lifting through the region will continue to bring
fairly widespread valley rain/mountain snow to northern
Utah/southwest Wyoming into the morning hours. The circulation
center is evident in satellite imagery and objective analysis
lifting through northeast UT/southwest WY early this morning. A
plume of weak low-mid level warm advection/pseudo-trowal
structure, accompanied by moisture wrapping around the back side
of this occluded circulation, is resulting in a broad area of
precipitation across the Wasatch Front/adjacent terrain. This
precipitation is also likely lake enhanced given a GSL lake
surface (~ 16C) to 700mb temperature (~ -4C per RAP analysis)
differential approaching 20C. Snow levels have fallen as low as
6000ft, and snow may be mixing in as low as 5500 feet based on web
cams along the Wasatch Back northeast toward Evanston.

Anticipate this precipitation to persist well into the morning
hours as these features are often very stubborn and tend to linger
longer than expected. Eventually as the low center continues to
move away from the area this forcing should diminish this
afternoon. Given this duration we`re likely looking at snow totals
in excess of 6" in the higher terrain of northern Utah above 8000
feet, and 2-5" below this level. This may end up including areas
around Park City, although would expect the PC area to become
increasingly shadowed as the low level flow takes on more of a
westerly component this morning.


As this system lifts out of the region later today, much cooler
temperatures and clear skies may allow min temps to reach the
freezing mark in portions of the western Uinta Basin, Castle Country
and west central Utah including areas around Delta. Have left the
going freeze products as is for now. Additionally, with today
moisture would anticipate areas of fog to develop in more
sheltered locations of northern Utah such as the Cache Valley and
areas of the Wasatch Back.

In the wake of today`s departing trough, a warming trend will ensue
heading into the upcoming weekend with daytime max temps rebounding
to near climo by Saturday across the CWA, then trending another 4-7F
warmer by Sunday as southwesterly flow strengthens ahead of the next
shortwave trough.

The majority of ensemble guidance (83%) is more progressive with
this early week shortwave trough, with the better upper forcing
brushing by northern Utah and pushing a relatively shallow frontal
boundary through the forecast area late Sunday (north) through early
Monday (south). This quick hitting solution would result in a
shorter window for precipitation largely confined to the northern
third of the CWA Sunday night into early Monday, while a small
minority (17%) of ensemble solutions are clustered around a slower
and deeper wave with a better chance for precipitation across the
CWA. The official forecast favors the faster solution, which brings
a strong but progressive front through the area late Sunday,
accompanied by a band of precipitation Sunday night, and followed by
with much cooler temperatures heading into early next week. In
the wake of this trough a gradual warming trend is forecast
through the end of the period.


&&

.AVIATION...KSLC...Light-moderate rain will continue through the
early morning hours until around 14-16z or so, with mostly MVFR
VIS/CIGs prevailing. Brief periods of IFR conditions are possible
(20% chance), particularly under any lake-effect showers which
will develop moreso by early morning. Showers will be much more
isolated during the afternoon, but may still produce periods of
MVFR conditions. Winds are likely to be light and variable through
the early morning, becoming more southerly after 15z before
transitioning to northwesterly sometime between 18-20z. Mountain
obscuration will continue through much of the day.

.REST OF UTAH AND SOUTHWEST WYOMING...Light-moderate valley
rain/mountain snow will continue through roughly 15z across northern
UT/southwest WY, with predominately MVFR VIS/CIGs and mountain
obscuration expected. Above ~6500ft, expect snowfall with MVFR-LIFR
conditions. After 15z, lake-effect rain showers may continue in the
area between KSLC-KOGD, with more scattered showers developing
across much of northern Utah during the afternoon. As clouds clear
by Thursday evening, some valleys could experience fog development
Thursday night (KLGU in particular is the most likely).

&&

.FIRE WEATHER...A low pressure system will continue to bring
valley rain and mountain snow to much of northern Utah through
this morning, mainly impacting areas east of I-15. This
precipitation will gradually wind down this afternoon as the storm
system begins to move away from the area. With the widespread
precipitation and cloud cover temperatures will run 10 degrees
below normal across the north. Meanwhile drier air has spread
across southern Utah overnight, which will result in increased
sunshine with temperatures a few degrees below normal today.

A warming and drying trend will follow for the remainder of the
week and into the upcoming weekend. Temperatures will climb back
to near normal by Saturday, and then trend a few degrees above
normal by Sunday as southwesterly flow temporarily develops and
strengthens. The next storm system will push a cold front through
the region Sunday night, with much cooler temperatures expected
Monday. Any precipitation with this system is expected to remain
confined to northern Utah Sunday night. Another warming and drying
trend will follow heading into the middle of next week.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Freeze Warning until 9 AM MDT this morning for UTZ114-120.

     Freeze Watch from late tonight through Friday morning for UTZ114-
     115-120.

WY...None.
&&

$$

Seaman/Cunningham

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