Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 021049

Area Forecast Discussion
National Weather Service Grand Junction CO
349 AM MST Fri Dec 2 2016

.SHORT TERM...(Today through Saturday)
Issued at 347 AM MST Fri Dec 2 2016

Currently the satellite water vapor image is showing a low
pressure system centered over Arizona advecting some moisture into
Utah and Western Colorado. KGJX Doppler Radar is showing some snow
showers associated with this moisture passing over the forecast
area this morning. This snow fall is light with the best radar
returns occurring just north of the I-70 corridor. A few bands are
also beginning to move through southwestern portions of the CWA.

Both the 0600Z GFS20 and NAM12 are showing diffluent southwesterly
flow aloft, sending some vort energy into southern Colorado Today
as an upper level boundary pushes in from the northwest. This
will result in light snowfall today into this evening tapering offovernight.
The main focus for this light snowfall will be south of the I-70
corridor, with the best possibility of snow expected over the San
Juan and West Elk Mountains. Total snow fall for these areas is
expected to be 2 to 3 inches with locally higher amounts possible.

.LONG TERM...(Saturday night through Thursday)
Issued at 347 AM MST Fri Dec 2 2016

The 0000Z ECMWF and 0600Z GFS20 have initialized well with the
current synoptic weather pattern and remain in good agreement
through roughly Monday morning. Both models are suggesting a dry
weekend with seasonally cool temperatures. Both models continue to
show a cold front passing over the area on Monday, which will
bring a return of snow and open the door for much colder

Behind the cold front on Tuesday 700mb temperatures are expected
to fall between -17C and -20C. This translates into day time
surface temperatures in the mid teens to mid twenties on Tuesday
and Wednesday, with the coldest temperatures north of the I-70
corridor and over the mountain areas. A slight warm up is
anticipated for Thursday as the cold airmass pushes to the east.
Snow will be likely with this event. However, exact snow amounts
are still outside of the range of the forecast. First guess snow
fall totals will be between 2 to 4 inches in the valleys with 6 to
10 inches in the mountains. Please keep an eye on the forecast as
details unfold.


.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 348 AM MST Fri Dec 2 2016

Overcast conditions are being reported at the terminals this
morning along with some patchy light snow showers. The current
water vapor satellite image is showing a low pressure system
centered over Arizona, pushing moisture into Utah and Southwestern
Colorado. This moisture along with an upper level disturbance will
support light snow throughout the day today, mainly over the San
Juan and Elk Mountains. For the most part VFR conditions are
expected at the terminals today with the exception of Durango and
Telluride which will see MVFR cigs and potentially reduced vis.
MVFR cigs will also be possible at terminals not supported by a
TAF, such as Steam Boat Springs.

Confidence on cigs and snow is moderate.




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