Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 011018

Area Forecast Discussion
National Weather Service Grand Junction CO
318 AM MST Thu Dec 1 2016

.SHORT TERM...(Today through Friday)
Issued at 251 AM MST Thu Dec 1 2016

The current IR satellite image is showing mid and high clouds
passing over the area this morning. These clouds are associated
with a weak cold front which is currently passing through central
Utah. Both the 0600Z NAM12 and 0000Z GFS20 show this front slowly
passing over the area today, bringing some light snow to Eastern
Utah and Western Colorado. The primary focus of the snow will be
north of I-70 today with the focus shifting to the southeast on
Friday. For the most part it looks like total snow fall from this
front will be 2 to 3 inches in the mountains with locally higher
amounts to 6 inches possible over the Eastern Uinta mountains as
well as the Flattops.

.LONG TERM...(Friday through Wednesday)
Issued at 315 PM MST Wed Nov 30 2016

Dry northwest flow will return to the region on Saturday morning.
The break in the action will be short lived however, as low-level
moisture and upslope flow combine to return some light snow to the
northern Park range from Saturday afternoon through early Sunday
morning. At the moment, the NAM remains a bit of an outlier
showing enough moisture to produce some light snow in the north,
with the GFS and ECMWF depicting a drier solution for now.

After several weak systems late this week and weekend, a dramatic
change is in store for early next week as a more potent trough
dives through the Pacifc Northwest on Monday. Medium-range
guidance is in good agreement on the first piece of energy with
this system bringing precipitation to eastern Utah and western
Colorado beginning early Monday morning and lasting through
daybreak Tuesday. Thereafter, notable differences between
deterministic models emerge. The GFS develops an area of low
pressure over eastern Utah producing significant precipitation
over much of the central Rockies. The ECMWF develops this low
farther south, keeping the heaviest precipitation south of the
Interstate 70 corridor. Regardless of the outcome, cold air will
be plentiful from Tuesday onward with GEFS ensembles showing
500mb height anomalies 2 to 3 standard deviations below mean
values. Rocky Mountain snow lovers will certainly want to keep an
eye on the forecast over the next several days.


.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 251 AM MST Thu Dec 1 2016

A weak cold front will slowly pass over the area today, bringing
mid and high clouds and the possibility of light snow to the
terminals. The main threat of snow will be from I-70 and north.
The weak nature of the front will result in generally light winds
throughout the day today into the evening hours.

Confidence is moderate to high.




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