214
FXUS65 KGJT 042337
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
437 PM MST Wed Dec 4 2024

.KEY MESSAGES...

- The Gunnison Valley and, to a lesser extent, the upper Yampa
  will continue to run colder than the rest of the forecast area
  due to strong low-level inversions.

- Expect mostly sunny skies and a gradual warming trend this
  week.

- Models coming into better agreement with a winter system impacting
  the area Sunday night into Monday. Snow amounts appear
  moderate with the northern and central Colorado mountains
  favored.

&&

.SHORT TERM /THROUGH THURSDAY/...
Issued at 319 PM MST Wed Dec 4 2024

Satellite imagery doesn`t have mush to look at because the airmass
across the Western States is so dry that there is hardly a cloud in
the sky, but some shower have popped up along the Mogollon Rim in
Arizona under the low and there are some wisps of high clouds
tracking west across southern Utah hinting that the models
initialized well with the Rex block over the Intermountain West.
This blocking pattern will continue with light if any winds through
the column in the col aloft going into the weekend before breaking
down, but you can read more about the weekend forecast below. Though
temperatures are running eight to ten degrees above normal, guidance
is still struggling to forecast temperatures running well above the
actual observations. Leaned heavy on the 5th percentile temps for
snow covered areas and the 10-25th percentile for areas with bare
ground. The inversion in the Gunnison Valley is still keeping temps
there well below normal with radiative fog and low stratus
developing each night. The upper Yampa River Basin around Craig saw
some fog this morning and may yet see it again tomorrow, but there
isn`t much confidence in it, maybe 50/50.

&&

.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
Issued at 319 PM MST Wed Dec 4 2024

A pattern shift looks likely for Sunday into Monday with the passage
of an upper-level trough. Ensemble guidance continues to favor a
trough increasing our confidence in the pattern change, however
there is still a lot of spread in the details at this time. Some of
these details include things like timing, track, strength, and
mositure content which will all have the potential to be
impactful to the forecast- especially winter weather amounts and
impacts. Right now the NBM is favoring light to moderate
snowfall in the northern mountains into the central mountains,
with light snow possible in the southern mountains. What is more
certain is the ability for this weather system to displace the
low-level inversions that have kept the snow-covered valleys
much cooler than the rest of the forecast area this week.
Elsewhere, a cool down ensues with a frontal passage on track to
arrive late Sunday/early Monday.

Dry air moves in behind this system resulting in decreasing
precipitation chances beyond Monday.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 436 PM MST Wed Dec 4 2024

VFR conditions and light terrain-driven winds are expected
through the taf period. The exception is the possibility of fog
at KGUC in the morning hours.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...None.
UT...None.

&&

$$

SHORT TERM...DB
LONG TERM...KAA
AVIATION...TGJT