610
FXUS65 KGJT 081716
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
1016 AM MST Wed Jan 8 2025

.KEY MESSAGES...

- Quiet and cool conditions continue today under a brief
  transitory ridge.

- Another winter disturbance will bring accumulating snow to the
  Uintas and the Colorado high country late tonight and
  Thursday. No winter highlights are expected, but blustery
  conditions will contribute to low visibility on mountain
  roads.

- A potentially more impactful storm is expected Saturday and
  Sunday with measurable snowfall for the Northern and Central
  Colorado mountains.

&&

.SHORT TERM /THROUGH THURSDAY/...
Issued at 351 AM MST Wed Jan 8 2025

Meridional flow digs southward across the Great Basin this morning.
This carves out the pinched low centered over Baja California at the
moment. A heavily tilted transitory ridge oriented west to east
across the CWA will pause active weather today. This weak high
pressure will have little impact on temperatures today as we keep
mostly normal winter-like temperatures in place this afternoon. Some
clouds will also stream through from the moisture spilling over the
upper ridge building along the West Coast. This will be mostly thin
high clouds and should allow some filtered sunshine to peek through.
Cold air reinforcements and additional moisture arrive late tonight
on that meridional jet streak as it organizes further. This will
push height falls and dig a trough into the Front Range. Light snow
will turn up on the Elk Heads and northern Park Range tonight, along
with the Uintas, as due north flow on the nose of the previously
mentioned jet streak kicks off a few orographic showers on favored
aspects. The Uintas stand to gain some of the best snow out of this
disturbance thanks to their unique east-west orientation. The high
country there will pick up 6-8 inches of new snow, while the eastern
shoulders along highway 191 will see 3-5 inches of snow by Thursday
afternoon. Have held back on issuing any highlights there due to the
sparse coverage of accumulating snow. Light snow will spread across
most of Colorado mountain zones early Thursday. Lack of forcing and
moisture will keep new accumulations under 4 inches for the most
part. Cold air and steep lapse rates will contribute to a few
over-performing showers in the Flat Tops, Central Mountains, and, to
a lesser extent, the San Juans. Strong winds aloft are expected to
keep breezy conditions on most of our terrain Thursday. This will
add to the visibility concerns under snow showers, likely creating
some brief whiteouts beneath strong outflows. The imposing West
Coast ridge begins to shove moisture east late Thursday afternoon
and is expected to turn off showers west to east.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Issued at 351 AM MST Wed Jan 8 2025

Some lingering snow showers will continue along the Divide as the
previous system continues to drop southward and associated upper
level trough does the same. Ridging then builds in Friday but a
strong jet will already be breaking down the ridge axis across the
PacNW. This jet will be supporting a more robust upper level trough
and surface cold front than we`ve seen lately. Forecast PWATs are
also expected to reach between 150 to 200% of normal values albeit
this jump in available moisture only lasts for about 8 to 10 hours,
if models are to be believed, early Saturday morning. As of now, the
GFS and EC are in fairly good agreement as are ensemble members. The
end result looks to be 6+ inches for the Elkheads, Park Range, Flat
Tops, and 4+ inches for the central mountains from Saturday morning
through Sunday morning. Even with confidence increasing in this
solution, will still take this with a grain of salt as models have
not performed especially well this season with snow amounts. One can
hope. Outside of the snow mentioned above, adjacent areas will also
see some chances (40 to 60%) for some showery precip.

Despite the front and trough pushing off to the east on Sunday,
general troughiness will remain across the CWA. Weak pieces of
energy will move through allowing some light snow showers to form
over the higher terrain for the remainder of the long term period.

Temperatures through the period will stay below the more usual mid-
January values.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1013 AM MST Wed Jan 8 2025

Quiet conditions at terminals will resume today as a weak ridge
of high pressure moves overhead. Winds will remain light.
Clouds will increase from the north later tonight as the next
winter disturbance approaches. Went ahead and placed VCSH in a
few terminals for tonight. Snow showers could cause MVFR
conditions at several sites and perhaps IFR at a few. Models
show the showers dissipating late in the period, but expect
cloud cover to hang around.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

SHORT TERM...LTB
LONG TERM...TGR
AVIATION...TGJT