Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 212212

Area Forecast Discussion
National Weather Service GRAND JUNCTION CO
312 PM MST Tue Nov 21 2017

.SHORT TERM...(Tonight through Wednesday night)
Issued at 312 PM MST Tue Nov 21 2017

Dry air will slowly filter into the region from the west as a
ridge of high pressure amplifies over the Desert Southwest.
Dispersing cloud cover has allowed temperatures to climb this
afternoon with some impressive temperature changes from the past
24 hours with current temperatures sitting some 10 to 15 degrees
warmer than this time yesterday. Available moisture in the lower
levels of the atmosphere remains scant so am confident in
continuing with the previous forecaster`s reasoning for just some
light snow flurries lingering over the northern mountains through
Wednesday. Otherwise, dry and benign weather will persist into
midweek as heights increase over the region. High temperatures
will jump an additional 5 to 10 degrees tomorrow with overnight
lows remaining above normal for this time of year.

.LONG TERM...(Thursday through Tuesday)
Issued at 312 PM MST Tue Nov 21 2017

By daybreak Thursday the center of the area of high pressure will
be anchored off the coast of southern California while a weak
upper level Pacific trough situated off the northwestern CONUS
gradually moves inland. As a result, it will be a beautiful and
pleasant Thanksgiving Day for eastern Utah and western Colorado
with mostly sunny skies, no precipitation, and well above seasonal
temperatures! Friday morning the aforementioned trough will have
migrated east and it will just barely clip our northern border
throughout the day which will generate light, isolated snow
showers to the Elkhead and Park Ranges and potentially the Gore
and Elk Mountains as well. Additionally, a ~120 knot jetstreak
will move overhead Friday afternoon to generate some breezy
conditions. High pressure will rebuild over the area for the
weekend for a mild and dry weather pattern.

Extended models begin to diverge at the start of the new work week
in regards to an approaching Pacific storm. While the timing of
the arrival of this system into the Great Basin appears to match
up pretty well at this point between the GFS and Euro, the
intensity, amount of available moisture, and depth of cold air
differs with the GFS being the drier solution at this time. As far
as the long term forecast goes, the progression of this upper
level trough early next week will be the main feature to watch
over the coming shifts.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1042 AM MST Tue Nov 21 2017

Some light snow showers will continue to impact the divide
mountains and passes of northwest Colorado with ASE and EGE TAF
sites seeing lower ceilings reaching ILS breakpoints at times due
to cloud cover. Conditions will improve after 21Z as drier air
moves in from the west, resulting in VFR conditions area wide with
light terrain driven winds. Some mountain turbulence is still
possible through this evening with stronger winds aloft as the
upper level jet remains overhead.




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