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National Weather Service Grand Junction Colorado
338 PM MST Tuesday Jan 27 2015

Short term...(tonight through Wednesday night)
issued at 336 PM MST Tuesday Jan 27 2015

Blanket of middle and high clouds with a few showers continues to
lift slowly north across eastern Utah and western Colorado this
afternoon. Cloud cover has helped to hold temperatures back a bit from
the record warmth experienced yesterday afternoon...with readings
down about 5 degrees across the board. This moisture is associated
with an upper level low lifting north across Nevada which slides
east across southern Idaho before dropping back into the plains on
Wednesday. Deeper moisture near the core of this wave will get
entrained in developing west-northwest flow across our northern zones
overnight with top down saturation bringing areas of snow to the
park and Gore ranges later this evening and through Wednesday
evening. Focus will be along the northern Park Range...which
could pick up 3 to 6 inches of new snow by late Wednesday night.
Areal impact of this event is small and in remote areas of Routt no highlights planned. Lingering low level
instability dissipates after midnight Wednesday night bringing an
end to this event. Cloud cover and shot of cooler air aloft
tonight and tomorrow will send temperatures down another few degrees in
most areas...but still well above our seasonal norms.

Long term...(thursday through tuesday)
issued at 336 PM MST Tuesday Jan 27 2015

A transient ridge will produce rather stable and benign weather on
Thursday with above normal temperatures. It will be mostly cloudy...with a
few light showers will be possible over the central and southern

Models continue in general agreement pointing toward a potential
winter storm Friday and Saturday focusing on SW Colorado. Split flow
pushes a Pacific trough across the West Coast Thursday and Thursday
night. The southern section becomes the dominant circulation over
northern Baja California as it moves into the southwest on Saturday before dropping
south into Mexico Sunday. Strong moisture transport into The Four
Corners is indicated on low- and middle-level isentropic surfaces in
nearly south flow Friday and Friday night but diminishes fairly
quickly north of the San Juans. Warm advection should result in snow
levels 7500-8500 feet...perhaps up to 9000 feet in the San Juans Friday per
wet-bulb zero forecast. Snow levels lower Friday night and Saturday
with cooler air. 12z models backed off a bit on snow accumulations
as best isentropic and q-g forcing stays just south. Early estimate
is for advisory snow amounts in the San Juans and southern valleys.
But uncertainty models hint at some hesitation with the
southward turn in the upper low over northwestern Arizona early Saturday. This
could lead to a bit longer duration of moist southerly flow into The
Four Corners. GFS also tries to briefly form a surface low in SW Colorado.
Will continue with the Special Weather Statement currently out for
SW Colorado.

Deformation axis indicated in the 700 mb wind field across the
Tavaputs to Flat Tops and should mark the northward extent of the
better chances of precipitation. Central mountains should also see
some snow accumulations mainly Friday night into Sat morning.

Drier air works northwest to southeast across the forecast area Sat
night as the upper trough moves into Mexico and ridging builds back
over the Great Basin. Pacific energy topping the ridge then brushes
our north Monday-Tuesday for a slight chance of snow in the northern mountains


Aviation...(for the 18z tafs through 18z Wednesday afternoon)
issued at 1006 am MST Tuesday Jan 27 2015

VFR conditions expected to persist at terminal sites through
midday Wednesday. However...isolated to scattered showers are
expected to develop overnight...mainly east of a line from kcag
to kril to kguc. Earlier forecast of showers approaching the
vicinity of kege and kase remains on track and tafs will reflect
this possibility later tonight through 15z Wednesday morning.
Mountains will be occasionally obscured after 06z this evening.


Gjt watches/warnings/advisories...


Short term...jdc
long term...jad

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