Area Forecast Discussion
Issued by NWS Grand Junction, CO

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000
FXUS65 KGJT 152357
AFDGJT

Area Forecast Discussion
National Weather Service GRAND JUNCTION CO
457 PM MST Mon Jan 15 2018

Updated and corrected portions of the 00Z Aviation discussion

.SHORT TERM...(Tonight through Tuesday night)
Issued at 255 PM MST Mon Jan 15 2018

Clouds and light showers associated with the cold front moving
along the Front Range is showing up well on visible satellite this
afternoon on an otherwise mostly sunny day. Isolated snow showers
have been confined to the northwestern Colorado mountains today
and this activity as well as any lower cloud bases will diminish
by this evening as the front dives to the southeast. A chilly
night is on tap for tonight, especially in northwest Colorado
under those clear, post-frontal skies.

A narrow ridge of high pressure will amplify overhead for Tuesday
keeping conditions dry and sunny. A weak and moisture-deprived
shortwave will move through eastern Utah and western Colorado
Tuesday evening through early Wednesday and result in a brief
period of increased mid and high level clouds and maybe a few
light snow showers in the eastern Uinta mountains.

.LONG TERM...(Wednesday through Monday)
Issued at 255 PM MST Mon Jan 15 2018

A short-lived ridge of high pressure will build over the region
Wednesday afternoon and Thursday while the main weather maker in
the long term, a cold, strong, and broad Pacific trough, deepens
off the west coast. Upper level flow will begin to turn to the
southwest Thursday evening as the trough moves inland. A strong
120-plus knot upper level jet will usher this system into the
Great Basin overnight Friday. Moisture will spill out ahead of
this system in the unsettled southwesterly flow so scattered
showers of rain and snow will develop as early as Friday morning
with coverage becoming more widespread Friday night and Saturday.
Latest model runs, though they have slowed down a bit, are
consistent in bringing the trough and an associated cold front
right through our forecast area before lifting this system into
the Plains Sunday morning. Preliminary snow totals are not too bad
and seem to favor areas north of I-70. Definitely a good shot of
cold air with this system as 700mb temperatures plummet to the -10
to -16 degrees C range. With this shot of cold air, snow levels
should lower to valley floors after midnight Saturday. Given this
system is still over 100 hours out, there are bound to be changes
in the models over the coming days, though the recent model
agreement is promising. This Friday night/Saturday system is
definitely the storm to watch so be sure to check back for the
latest updates throughout the week.

A transitory ridge of high pressure looks to set up in this
storm`s wake on Sunday, though some orographic showers will likely
linger over the northern mountains in the favorable northwesterly
flow. Extended models diverge on potential solutions for the next
disturbance as we head into the new work week but a more
progressive weather pattern looks to prevail from Monday onwards.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 457 PM MST Mon Jan 15 2018

Low ceilings below ILS breakpoints around 4k to 5kft will persist
through the evening along the divide areas (including KEGE and
KASE), as well as KVEL outside the divide where some stratus is
trapped under an inversion. These clouds are associated with a
front moving through the area from north to south. Brief period of
gusty winds to 20 kts will also occur in the vicinity of this
front as it tracks southward trough the area, which should die
down after sunset. After 06Z, Skies should clear for the most
part aside from some thin high cirrus with VFR conditions
prevailing through Tuesday.

&&

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

$$

SHORT TERM...MMS
LONG TERM...MMS
AVIATION...MDA


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