269
FXUS65 KGJT 160419
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
919 PM MST Wed Jan 15 2025

.KEY MESSAGES...

- Slightly warmer conditions are on the way as high pressure
  builds over the area. The exception will continue to be the
  high snow covered valleys where cold air remains trapped and
  cold temperatures will persist.

- Changes arrive by the weekend as an arctic front dives through
  area early Saturday and spread snow and cold back into the
  forecast.

- A strong arctic outbreak is expected to end out the weekend
  into early next week across the central CONUS. The coldest
  air should remain East of the Divide but temperatures on this
  side will end up well below normal. Overnight lows have a high
  probability of dropping well below zero in many mountain and
  high valley/basin areas.

&&

.SHORT TERM /THROUGH THURSDAY/...
Issued at 155 PM MST Wed Jan 15 2025

A ridge building over the Pacific Northwest noses into our region
allowing temperatures to warm up for most locations. This is not a
big swing in temperatures, but perhaps 5 degrees or so. A few of
those high snow covered valleys stuck in strong inversions might not
warm up much at all. These locations continue to be a challenge with
regard to temperature forecasts. Been going with the lowest
percentile of guidance and sometimes that is not enough. The warm
advection is also drying things out so the snow machine will shut
down for a brief period as well. The ridge begins to break down
tomorrow as a cut off low passes to our south and a system comes in
from western Canada. Condition still remain dry with some passing
clouds.

&&

.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
Issued at 155 PM MST Wed Jan 15 2025

The focus of the extended forecast is the arrival and residence of
an Arctic airmass. A longwave trough digs southward across much of
the CONUS this coming weekend with an arctic front progged to slide
through on Saturday. Periods of light snow are likely with the
frontal passage resulting increasing snowfall chances over the high
valleys and up to a few inches possible in the mountains. Overall,
snowfall does not look to be the primary threat with this system in
western CO and eastern UT. However, if you are traveling this
weekend, confidence is growing for impactful snowfall on the Front
Range so plan accordingly. Bitter cold wind chills are the main
threat in our forecast area with the coldest conditions currently
forecast on Tuesday morning. Some of the upper valleys could see
wind chills in the -20 to -40 range with the lower valleys in the 0
to -15 range. Cold Weather Advisories and Warnings may be needed in
some valleys early next week so be sure to continue to monitor the
forecast as we hone in on the potential impacts from this
system.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 917 PM MST Wed Jan 15 2025

Clear skies, light, terrain driven winds, and VFR conditions
will prevail for the next 24 hours. Strong drainage winds up to
20 knots will be possible at KHDN through 12z.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

SHORT TERM...KJS
LONG TERM...KAA
AVIATION...TGJT