685
FXUS65 KGJT 230448
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
948 PM MST Fri Nov 22 2024

.KEY MESSAGES...

- Partly/mostly cloudy skies Saturday with mild temperatures
  continuing.

- Snow returns, mainly across the north, Saturday night and
  continues through Monday morning as a weak disturbance fed by
  the ongoing Atmospheric River (AR) moves over the area.

- After shifting south of the area Monday night, the AR lifts
  northward and threatens prolonged periods of heavy mountain
  snow Tuesday through Thanksgiving Day. Significant snowfall
  is possible.

- What`s more certain is that if you`re planning on traveling
  Tuesday and Wednesday before Thanksgiving, you face a high
  likelihood of winter driving conditions.

- Pay close attention to the latest forecasts as snow amounts
  and storm timing may change over the coming days.

&&

.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 301 PM MST Fri Nov 22 2024

Dry and relatively mild conditions continue today and tonight as
the jet and ongoing Atmospheric River (AR) remains north of the
area. However, cirrus and altostratus will increase over the
next 24 hours resulting in partly cloudy to mostly cloudy
conditions across the region. Despite the clouds, highs on
Saturday are expected to continue to run close to 5 degrees
above seasonal norms. Our first brush with the AR comes Saturday
night as a westerly propagating short wave causes it to drift
southward flowing over the northern half of the forecast area.
Moderate mid and upper level forcing combined with orography is
expected to generate snow, first over the eastern Uinta
Mountains then, potentially, over the Elkhead and Park Mountains
late Saturday night. Operational runs weren`t in great
agreement over northern Colorado and have some concerns that
snow will hold off there until Sunday morning. Given uncertainty
and marginal snow amounts indicated opted to hold off on any
highlights for now.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 301 PM MST Fri Nov 22 2024

Details regarding the upcoming storm system beginning this
weekend are coming into clearer focus as model agreement
improves. Sunday will provide a brief glimpse of what`s to come
as a shortwave trough and associated cold front will push
through the region. 4 to 8 inches of snowfall with locally
higher amounts is expected over the Uintas, Flat Tops, and
northern CO mountain ranges, bringing these locations to
advisory-level criteria. Central CO ranges are teetering on the
edge of advisory-level snowfall with the NBM indicating a 40-60%
chance of 4+ inches of snow on Sunday.

Deterministic models suggest in good confidence that a break in
precipitation over the CWA will begin around late Monday morning
as brief ridging occurs behind the trough. This should persist
until moisture from the ongoing atmospheric river advects into
the region late Monday/early Tuesday morning. The northern and
central CO ranges, San Juans, and La Sals all look to receive
between 1 to 2 feet of snowfall with this system. Accumulations
may push beyond these values in the Elk and West Elk ranges, but
confidence in this high-end scenario remains low at this point
in time. The Roan Cliffs and Abajos are also on tap for 6 to 10
inches of snow. Lower valleys are expected to see little
precipitation, if any. To note, trends continue pushing the
deepest moisture farther and farther south, leaving some
uncertainty regarding the placement of highest snowfall
accumulations. Northern portions of the CWA may begin to see
storm totals lower in upcoming model runs should this southward-
moving trend continue.

The messaging regarding Thanksgiving travel remains the same.
Mountain passes may see significant snowfall throughout the
the region. Therefore, it is important to stay updated as
forecasts will evolve over the coming days.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 948 PM MST Fri Nov 22 2024

VFR conditions will prevail over the next 24 hours with high
clouds increasing in coverage overnight into Saturday. Winds
aloft also increase which will lead to some LLWS at mountain TAF
sites after 08Z or so. Included LLWS at KASE, KEGE, KTEX and
KHDN. Gusty winds have a better chance of reaching the surface
at these sites Saturday afternoon with light, terrain driven
winds at the surface in the lower valleys.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

SHORT TERM...NL
LONG TERM...BW
AVIATION...TGJT