839
FXUS65 KGJT 052338
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
438 PM MST Fri Dec 5 2025

.KEY MESSAGES...

- A winter weather system arrives tonight with more widespread
  accumulations and stronger winds at the high elevations.
  Winter Storm Warnings and Winter Weather Advisories are in
  effect for portions of the Colorado mountains this evening
  through Saturday evening.

- Unsettled weather continues through the coming work week in
  the northern Colorado mountains with mostly periods of light
  snow showers.

- A general warming trend is expected, but the snow covered
  mountains valleys will see cold inversions set up overnight
  lasting through the days.

&&

.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 258 PM MST Fri Dec 5 2025

Radar imagery and traffic cameras have shown snow falling
throughout the day, primarily in the northern and central
Colorado mountains. Over the next few hours a lull in snowfall
is expected, but late this evening rates should begin to
increase again, first in the northern mountains, as anomalous
atmospheric moisture advects into the area from the northwest.
This plume of moisture looks to carry PWAT values around 200%
of normal, and will quickly move across the region through
Saturday. Both the forcing from the synoptic pattern, and
orographic lift, will support accumulating snow across our
terrain. The northern mountains are expected to get the most
snowfall from this event, as favorable orographics occur with
the prevailing northwesterly flow in place. The Park Range in
particular could see one or two feet of snow, perhaps even more
at the highest elevations. Snow totals generally came up a bit
for most mountain areas in the latest forecast package, so a
Winter Weather Advisory was issued for the northwest San Juan
Mountains above 9000 feet from 11 PM this evening through 11 PM
Saturday. The other Advisories and Winter Storm Warnings issued
remain in place.

The synoptic setup will allow for upper level support from
narrow waves of energy embedded in the flow, and some additional
support from diffluence and the positioning of the jet aloft.
The timing of the increased moisture and upper level support
will result in the greatest snowfall rates occurring late
tonight through Saturday morning. However, snow is expected to
continue through Saturday evening. In addition to the falling
snow, strong wind gusts exceeding 30 to 40 mph in some areas of
higher terrain may create blowing snow conditions tonight
through tomorrow afternoon. As such, hazardous travel conditions
are possible, and travel may be very difficult to impossible at
times during this winter weather event.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 258 PM MST Fri Dec 5 2025

The bulk of the heaviest snow should be done by sunrise on Sunday
but a moist dendritic layer over the northern and central divide
mountains through early afternoon will keep showers going. Warm air
advection kicks in through the afternoon as the jet shifts onto the
Plains and this stabilized the column and most showers should be
ending by sunset. Next week a ridge builds over the West Coast,
which will steer the jet stream to our north. Also, the ridge will
cause temperatures rise to 10 degrees above normal by mid week. The
northern mountains could get clipped by moisture advecting through
the ridge, which may result in snow showers. As of now those amounts
are minor. Valleys in deeper snow could experience strong inversions
despite the warm advection. That means temperatures could end up
cooler than the going forecast.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 435 PM MST Fri Dec 5 2025

Low clouds linger across much of eastern Utah and western
Colorado, with many locations experiencing ceilings below
breakpoints. This will continue through the next 24 hours, as
the next storm moves in. Higher elevation sites and terminals
along and north of I-70 have the highest chances of seeing snow
beginning after 03z this evening, and lingering through 18z
tomorrow afternoon. Winds will be strong and northwesterly, with
gusts up to 25 knots possible for higher elevation terminals.
LLWS will be an issue for most terminals tonight. VFR to MVFR
conditions will prevail, with drops to IFR/LIFR likely,
especially for KASE, KTEX, and KHDN. Conditions will begin to
gradually improve after 18z tomorrow.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...Winter Weather Advisory until 5 PM MST this afternoon for
     COZ004.
     Winter Storm Warning until 11 PM MST Saturday for COZ004-013.
     Winter Weather Advisory until 11 PM MST Saturday for COZ005.
     Winter Weather Advisory from 11 PM this evening to 11 PM MST
     Saturday for COZ008-009-018.
     Winter Storm Warning from 11 PM this evening to 11 PM MST
     Saturday for COZ010-012.
UT...None.

&&

$$

SHORT TERM...GF
LONG TERM...KJS
AVIATION...TGJT