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Area forecast discussion 
National Weather Service Grand Junction Colorado
302 PM MST sun Feb 1 2015

Short term...(tonight through Monday night)
issued at 302 PM MST sun Feb 1 2015

Nearly clear skies advected over the area overnight and this
morning with plenty of sunshine burning of fog and low stratus in
some valleys around noon. The next batch of clouds and precipitation will
move in quickly tonight. The northwest flow will gradually
moisture up...beginning an extended period of northwest orographic flow
and precipitation over the Colorado northern and central mountains. This northwest
flow aloft will remain static through Monday night...but 2 weak
shortwave troughs will ride this flow across southern Wyoming and
northern Colorado. The first will enhance the orographic precipitation after
06z tonight through Monday morning. The second will begin
enhancing the orographic affects late Monday night. Have increased
the cloud cover and the chance of rain over the northern third of
the area tonight and Monday morning and again late Monday night.

Long term...(tuesday through sunday)
issued at 302 PM MST sun Feb 1 2015

These periods begin with minor disturbances passing in northwest flow
that will favor the northern Colorado mountains with showers.
These disturbances lack good upper level support or even much
temperature advection except maybe on Wednesday. Moisture amounts
look good with precipitation water values over northwest Colorado at near 0.5 inches.
The NAM seems to be over-producing quantitative precipitation forecast in this regime...but the
GFS has increased precipitation amounts for the Tuesday night Wednesday
time frames. Highlights may be be needed mainly for the
park/Gore/Flattops with less amounts in the Elk Mountains northwest winds at
mountain top level of 20-35 miles per hour threaten areas of blowing snow
especially over Rabbit Ears Pass. Mild temperatures will produce a
rain/snow line near 7000ft.

Northern Colorado snow ends Wednesday night as the western ridge
progresses. Temperatures climb to 10-15 degrees above normal by
the weekend. A disturbance passes over the ridge through Wyoming
on Saturday that will mostly just increase mountain gradient winds.
There are hints that the ridge will break early in the second week
of February.


Aviation...(for the 18z tafs through 18z Monday afternoon)
issued at 302 PM MST sun Feb 1 2015

VFR conditions will prevail across the area until about 06z.
Layered middle and high cloud will spread over the northern and
western portions of the area overnight as a weak disturbance moves
through Wyoming and eastern Colorado. Snowfall will increase of
the northern Colorado mts north of Interstate 70...produces locally
obscured mountains. The precipitation area and Montana obscurations will
gradually increase over NE Utah and central Colorado...but flight
conditions at the taf sites will remain VFR through Monday.


Gjt watches/warnings/advisories...


Short term...cirrocumulus
long term...Joe

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