508
FXUS65 KGJT 222228
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
328 PM MST Wed Jan 22 2025

.KEY MESSAGES...

- Light snow continues in the Colorado mountains tonight where
  in general, an additional 1 to 2 inches are expected.

- Temperatures continue to warm up during the latter half of
  the week.

- Another system is possible this weekend and early next week.
  It could bring more widespread snowfall to the area.

&&

.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 322 PM MST Wed Jan 22 2025

A low amplitude mid-level short wave trough continued to sweep
south-southeastward across the area this afternoon. Lift and
instability brought by this feature continued to generate light
snow from the northern mountains into the northwest San Juan
Mountains during the day according to webcams and observations.

Showers will decrease early this evening in the wake of the
previously mentioned short wave, but ramp back up later this
evening into the early morning hours as a second, weaker short
wave trough moves over the northern and central Colorado
mountains. As mentioned in previous discussions, models
indicated little moisture available in the colder air
propagating from the north, so additional accumulations will be
light with generally 1 to 2 inches of new snow anticipated.

Drier air fills in behind the second disturbance so we`ll see
showers over the northernmost mountains erode through the
morning on Thursday. A transitory positive tilt ridge develops
over the area Thursday sustaining the break in snow.
Clear/mostly clear skies are expected through Thursday evening
with clouds increasing across the north late Thursday night
ahead of the next system approaching the area. More on that in
the long term discussion.

Cold air will remain entrenched beneath strong inversions which
have held since the arctic surge arrived this weekend. Areas
within the thermal belt along mountain flanks will continue to
see temperatures moderate in a warm air advective environment.
In contrast, areas below the inversion will be slower to recover
with temperatures gradually becoming less cold during the
period.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 322 PM MST Wed Jan 22 2025

Models show good agreement with continued ridging off the Pacific
Northwest and a deep cold longwave trough from the Front Range east
across the CONUS keeping eastern Utah and Western Colorado under a
northerly flow aloft. A shortwave descends in this flow Friday to
form a cutoff low in the Great Basin Saturday that drifts southwest
over California and southeast into the Desert Southwest Sunday into
early next week. This pattern shifts the flow aloft to the southwest
to bring a return of temperatures to near to a little above normal.
The exception will be the northern areas generally north of the I-70
corridor where temperatures will dip again over the weekend as the
trough associated with the low to the west moves across the region.
The cooler temps will be more from the cloud cover and showers
limiting diurnal heating. The dynamics with the troughiness and the
right entrance region of the jet going overhead will bring snow
showers to most of the higher terrain Saturday and Sunday. The lack
of moisture will temper snow amounts to generally just a few inches,
but the higher mountain passes could see six to nine inches over the
extended period. Weather headlines are not likely at this time, but
can`t rule out an advisory for minor to moderate impacts as we get a
clearer picture of this system. Stay tuned.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1034 AM MST Wed Jan 22 2025

Expect mid to low ceilings with scattered snow showers through
the northern and central Colorado mountains through 12Z with
periods of MVFR and brief IFR conditions at mountain TAF sites.
Look for periods of conditions below ILS breakpoints at KASE,
KEGE, KRIL, KHDN and KTEX, especially with passing snow showers.
Gusty northerly winds pick up this afternoon with peak gusts over
25 mph TAF sites lasting into the early evening before the
inversion quiets them.

&&

.HYDROLOGY...
Issued at 936 AM MST Wed Jan 22 2025

Ice build up during the past few days of colder temperatures
could release as temperatures become more moderate today through
the end of the week.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...Flash Flood Watch through Friday evening for COZ008-010.
UT...None.

&&

$$

SHORT TERM...NL
LONG TERM...DB
AVIATION...DB
HYDROLOGY...NL