437
FXUS65 KGJT 212347
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
447 PM MST Thu Nov 21 2024

.KEY MESSAGES...

- High pressure remains in control heading into Saturday with
  partly cloudy skies expected. Warm temperatures continue.

- Snow returns late Saturday night as an Atmospheric River sets
  up across the area. This AR may persist through Wednesday
  bringing periods of heavy snow to the mountains.

- If you`re planning on travelling during Thanksgiving week,
  especially over any mountain passes, please pay close
  attention to the latest forecasts as amounts and timing will
  likely fluctuate over the coming days.

&&

.SHORT TERM /THROUGH FRIDAY NIGHT/...
Issued at 230 PM MST Thu Nov 21 2024

Other than some high clouds at times skies will be mostly
clear. A ridge of pressure is building over the region keeping
us dry and gradually warming temperatures. By Saturday highs
will be 5-10 degrees above normal while lows will be pretty
close to average. Over the next 48 hours the strong low pressure
system in the Pacific Northwest will shed a piece of energy
that ejects inland. This trough tracks over the Northern Rockies
and eventually sends a cold front along with some moisture into
the area. This looks like it will not happen until late
Saturday.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 230 PM MST Thu Nov 21 2024

Southwesterly flow sets up across the region on Saturday ahead
of the low pressure system which is currently impacting the
PACNW. High temperatures across the CWA are likely to exceed
normals by 5-12 degrees underneath this pattern. Moist
conditions look to push into the Intermountain West on Saturday
as well, though precipitation doesn`t seem to be on the table
for most of the area aside from a small possibility of snow
(15-30%) over the northern CO mountains and eastern Uintas.
Impacts become more notable on Sunday and early Monday as a
shortwave trough ejects across Wyoming and northern CO. The
ECMWF and GFS have some variation in the timing of this system
with the ECMWF exhibiting a lower-amplitude trough that transits
across the region quicker than the GFS. Regardless, both models
suggest this is when our next stretch of wet conditions will
begin.

A stronger surge of moisture is poised to advect into the area
starting Monday as the AR connected to the PACNW low dips south
of the Sierras. Precipitation over higher elevations may persist
through Wednesday or even early Thursday. Highlights will be
possible at all mountain ranges during this period, with current
guidance indicating the central CO mountains are to see the
greatest snowfall totals. However, run-to-run storm totals
continue to vary greatly. With the volatility of these
forecasts, these estimates could certainly continue to wobble as
we approach the weekend, so it is difficult to speculate at
this time what to expect in terms of snow accumulations. What
has remained consistent though is the expectation for high
temperatures in the mid-40`s in lower valleys, thus
precipitation in these locations is expected to fall as rain.

This event is setting up to linger over the region through late
next week, meaning travel for Thanksgiving will be impacted,
especially over mountain passes. Stay updated with the latest
forecasts as the system approaches.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 445 PM MST Thu Nov 21 2024

VFR conditions will prevail over the next 24 hours with mostly
clear skies expected, although some high cirrus will stream
overhead from time to time, more prevalent across the north.
Winds will remain light and terrain driven with breezy
conditions overnight at KHDN.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

SHORT TERM...KJS
LONG TERM...BW
AVIATION...TGJT