Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 070503
AFDGJT

Area Forecast Discussion
National Weather Service GRAND JUNCTION CO
1003 PM MST Wed Dec 6 2017

.SHORT TERM...(Tonight through Thursday night)
Issued at 140 PM MST Wed Dec 6 2017

Water vapor imagery is currently showing some drier air
undercutting the weak shortwave that is moving southward through
Wyoming and northern Colorado. This dry air is entrenched across
much of central and southern Utah into southwest Colorado. Do not
expect too much in the way of snow accumulation over the mountains
with this weak shortwave today with a few flurries due to the dry
atmosphere. Another wave comes in on the heels of this one on
Thursday, clipping the northern divide mountains again for maybe a
couple inches of light snow at best among the higher peaks.
Clouds will increase across the northern and central divide
mountains but otherwise, expect mostly sunny skies for most areas
due to the lack of moisture. While snow and moisture may not be
much of a player through Thursday with these weak shortwaves, one
thing that will be a player is the cold air mass that moves in
this evening. H7 temps lower to between -10C and -16C across the
entire forecast area down to the Four Corners tonight through
Thursday afternoon. Therefore, lowered afternoon highs and
overnight lows today through Thursday night and trended more
towards the non-bias corrected guidance as it looked more
reasonable. Expect near normal temps this afternoon lowering to
below normal through Thursday night.

.LONG TERM...(Friday through Wednesday)
Issued at 140 PM MST Wed Dec 6 2017

What more is there to say other than that strongly amplified ridge
of high pressure along the western states, stretching from the
Baja to as far north as the Aleutian Islands in southern Alaska
will hold strong through at least mid December, which is as far
as the model forecasts go. This will result in dry conditions
with not much chance of precipitation as any disturbances hitting
this ridge will take a while to ride up and over the top of the
ridge and weaken as they reach Colorado, resulting in some high
clouds from time to time. Bottom line: the stubborn ridge of high
pressure is not budging. The biggest forecast challenge is the
temperatures, as valley inversions strengthen under this ridge,
slowing the warming trend through the weekend and into next week.
The nighttime lows especially will feel colder compared to where
we have been with highs gradually reaching near normal by Friday
and above normal late in the weekend into next week. Lowered
temps through the weekend in order to show a more gradual warming
trend heading into next week.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1003 PM MST Wed Dec 6 2017

VFR conditions will prevail over the next 24 hours. Mid and high
level clouds will increase for areas north of I-70 as a weak
disturbance drops into the region around sunrise. Strong
northerly winds aloft will have some impact to surface winds with
some gusts up to 35 kts possible during the afternoon hours along
with some light snow showers for the northern mountains.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...None.
UT...None.
&&

$$

SHORT TERM...MDA
LONG TERM...MDA
AVIATION...TGJT



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