189
FXUS65 KSLC 062210
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
310 PM MST Sat Dec 6 2025

.SYNOPSIS...Northwesterly flow will remain in place through the
week ahead with windy conditions developing across southwest
Wyoming and the Uinta Basin by mid week. There is 25% chance that
the northern Utah mountains will see warm atmospheric river
moisture return by midweek, with a 75% chance that minimal
moisture and windy conditions persist.

&&

.DISCUSSION...

KEY MESSAGES:

- Generally breezy northwesterly flow will remain in place across
  northern Utah and southwest Wyoming through the week ahead, with
  a medium chance of exceeding 45 mph wind gusts across Southwest
  Wyoming and Western Uinta Basin Tuesday into Wednesday.

- There is a 25% chance that warm atmospheric river moisture
  returns to northern Utah by Wednesday, which could produce 1-2
  inches of water equivalent in the mountains with high snow
  levels and dense snow. Otherwise, there is a 75% chance that
  moisture remains to our north brining minimal precipitation and
  otherwise windy conditions for the mountains.

- Temperatures will moderate through the week with northwesterly
  flow in place, which is also expected to minimize the threat for
  inversion conditions across northern Utah Valleys.

This evening precipitation has largely diminished across the area
except for isolated snow showers over the higher terrain. These
snow showers are developing in the modest instability and strong
flow behind the cold front, and thus the highly un-blocked flow is
resulting in snow showers extending well downstream from the crest
of the higher terrain. Thus additional snow accumulations or
impacts are expected to minimal in the mountains through the
evening. As such have canceled all Winter Storm Warnings.

Quiescent conditions will resume Sunday and Monday in the wake of
the departing storm system will generally northwesterly flow still
in place. As we move into Tuesday and Wednesday, an upstream
ridge will strengthening, centered along and offshore of the West
Coast, with troughing remaining in place over the central CONUS,
placing using in strengthening northwesterly flow in the middle.
In this pattern an impressive Atmospheric River will penetrate
inland through the Pacific Northwest and into the Northern
Rockies. However, where some ensemble members have been showing a
trend over the last 24 hours has been toward one potential outcome
(25% chance) where the downstream trough is more amplified, thus
helping to push the AR moisture trajectory into northern Utah.
Thus the forecast is an interesting one because the most likely
outcome (75%) is that the moisture will remain to our north,
keeping northern Utah and southwest Wyoming just in the drier air
but with still windy conditions. Thus the highest probability
outcome is minimal precipitation for the northern Mountains with
generally wind conditions. However if the AR moisture trajectory
is more southerly then we would be in for another round of
potentially impressive SWE amounts of 1 to 2+ inches over the
Northern Mountains. This would event have potential to be a
slightly warmer system than the one that just moved through, thus
snow levels would be quite high and snow densities above the snow
level would be very high as well. Thus while this is currently a
lower chance event, the impact could be high for the mountains,
especially when considering the windy conditions that would
accompany the precipitation.

Otherwise, despite what happens with the precipitation winds will
increase, with the best potential for lower elevation impacts
from winds coming across Southwest Wyoming. There there is a
greater than 66% chance of exceeding 45 mph, and greater than 33%
chance of exceeding 58 mph (or High Wind Warning) level wind gusts
Tuesday into Wednesday, with the highest chances on Wednesday.
The Western Uinta basin could also do well in this westerly flow,
but being farther south the probabilities are bit lower than
southwest Wyoming, with about a 33% chance of exceeding 45 mph on
Wednesday (Wind Advisory levels).

&&

.AVIATION...KSLC...Northwesterly winds will continue at the terminal
through 02-03Z before shifting to the southeast. Otherwise, little
impact to the weather through the period.

REST OF UTAH AND SOUTHWEST WYOMING...Outside of a few snow showers
across the mountains of northern and central Utah, conditions will
continue to improve across the region as a storm system moves out of
the area. That said, there is a 20% chance of patchy fog/MVFR
conditions in the northern valleys overnight tonight.

&&

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...None.
WY...None.

&&

$$

PUBLIC...Church
AVIATION...Kruse

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