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Area forecast discussion 
National Weather Service Grand Junction Colorado
327 am MDT Sat Nov 1 2014

Short term...(today through sunday)
issued at 324 am MDT Sat Nov 1 2014

Mild conditions will continue across the forecast area today ahead
of a cold and splitting longwave trough that will be shifting
into the Great Basin by this afternoon. Deep and increasingly
moist southerly flow will be in place today with breezy to windy
conditions anticipated as surface gradients tighten in battle between
warmer air mass in place and colder conditions advancing eastward
across Utah. Latest short range models continue to advertise an
active morning period as weak wave ejecting out and over the
forecast area arrives. Lightning activity has continued to pick-up
across southeast Utah and latest hrrr model drives this activity
northeast into western Colorado by sunrise with activity
diminishing by midday. Winds will be the biggest concern with any
storms that develop with gust potential in excess of 45 miles per hour. 700 mb
speeds peak around 15z and then slowly taper off as gradients
relax this afternoon. At this time...not planning on any wind highlights
with rain hitting the valley momentum Transfer likely
hindered a bit by low level moisture sneaking in. Will keep temperatures
near values experience yesterday...with a few degrees of cooling
for the mountains and southwest Colorado valleys where showers
will be most prominent today.

As the Pacific trough moves across the Great initial
wave of energy splits off and lifts to the northeast Saturday
evening. Some light precipitation will continue in the warm sector
of the storm ahead of the cold front associated with this system.
The front will push across eastern Utah in the evening is prognosticated
to stall roughly along a kdwx to 20 to 30 miles east of kpga line
by 12z/sun. Precipitation will focus along this boundary and in
the southern Colorado mountains as a 100kt jet noses into The Four
Corners region. Increased moisture and lift will bring a strong
likelihood for showers elsewhere as well. Meanwhile...7h temperatures
fall to near zero along the boundary and snow should begin
accumulating in the higher elevations at this point. The front
remains stalled over the area Sunday as a relatively balanced jet
moving through the southern branch of the trough holds the system
in place. Overnight lows will be a bit cooler Saturday night as
the cold front eases over the area. However...clouds and moisture
will mitigate the impact of cold air advection. Clouds... precipitation and
colder air will lead to markedly cooler afternoon highs on Sunday.

Long term...(sunday night through friday)
issued at 324 am MDT Sat Nov 1 2014

The system finally begins tracking slowly eastward Sunday night
and Monday. Precipitation will remain fairly widespread during
this period with snow levels lowering below 8000 feet. Given the
persistent nature of the precipitation with this slow moving
system have decided to issue a Winter Storm Watch for mountain
areas above 9500 feet aligned with the stalled front from Sunday
through Monday afternoon. Specifically...this watch will include
the mountains of southeast Utah...the Grand Mesa...and The Flat
Tops. Also included are the western San Juan Mountains where
orographics and dynamics favored. Accumulations above this level
could potentially range from 4 to 8 inches with up to a foot
possible on higher southwest facing slopes. Understandably...
temperatures will continue to run below normal Monday.

Flat ridging will be building back over the region Tuesday with a
slow warming trend anticipated. With the ridge comes drier
conditions with little to no precipitation expected through the
end of the week.


Aviation...(for the 12z tafs through 12z Sunday morning)
issued at 324 am MDT Sat Nov 1 2014

Scattered showers and isolated thunderstorms will occur across
much of eastern Utah and western Colorado through 18z today. After
18z...activity is expected to become more isolated in nature and
confined to the higher terrain of western Colorado and northeast
Utah. Another surge of moisture arrives after 06z tonight with
showers again expected by early Sunday morning. Expect areas of
MVFR ceilings and obscured mountains today. Gusty southwest winds in
excess of 40kts can also be expected through 03z this evening.


Gjt watches/warnings/advisories...
Colorado...Winter Storm Watch above 9500 feet from late tonight through
Monday afternoon for coz009-012-013-018-019.

Utah...Winter Storm Watch above 9500 feet from late tonight through
Monday afternoon for utz028.



Short term...jdc/nl

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