Area Forecast Discussion
Issued by NWS Grand Junction, CO

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000
FXUS65 KGJT 041411
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
711 AM MST Sun Dec 4 2016

.UPDATE...
Issued at 711 AM MST Sun Dec 4 2016

Updated the forecast to include fog this morning in the southwest
Colorado valleys...particularly the Animas Basin which includes
Durango and the Highway 160 and 491 corridor up through Dolores
and Cahone. Fog should burn off with sunrise.

&&

.SHORT TERM...(Today through Monday)
Issued at 505 AM MST Sun Dec 4 2016

Mostly clear skies are being reported around the area this
morning. Under these clear skies temperatures have fallen into the
mid single digits to mid teens at most locations with upper teens
to low 20s in the Grand Valley. Currently it is 21 degrees at
Grand Junction airport. After a cold start to the day temperatures
will rise into the mid 20s to mid 30 at most locations with mid to
upper 40s near the Four Corners.

Monday will be a day of change as a cold front begins to push into
Northern Utah and Northern Colorado. This cold front will bring
potentially heavy snow to the mountains beginning late Monday
morning persisting into Tuesday evening. At lower elevations in
Northeastern portions of the CWA 2 to 3 inches of snow will be
possible with 4 to 8 inches beginning around 3500 feet and 8 to 12
inches expected in the higher elevations. This event has prompted
a Winter Storm Watch for portions of the Elkhead, Park, Gore and
ELK Mountains as well as the Central Mountain Valleys, West Elk
and Sawatch Mountains as well as the Flattops. Please see
DENWSWGJT for more details.

.LONG TERM...(Monday night through Saturday)
Issued at 507 AM MST Sun Dec 4 2016

The 0000Z ECMWF and 0600Z GFS20 have initialized well with the
current synoptic weather pattern this morning and remain in good
agreement through at least Friday. As previously mentioned a cold
front will begin to push into the area on Monday and both of these
forecast models show cold arctic air moving into Northern Colorado
behind the front.

In fact 700mb temperatures north of I-70 on Monday night will
fall to -12 to -15 C which will bring surface temperatures into
the single digits. By Tuesday night 700mb temperatures will
continue to fall to -15 to -20 C across the CWA, with the coldest
temperatures in the northern half of Utah and Colorado. This will
result in cold daytime temperatures with widespread single digit
overnight temperatures and widespread negative temperatures for
northeastern portions of the CWA. These cold temperatures will
stick around Wednesday before beginning to warm on Thursday.

A warming trend is expected to begin on Thursday with afternoon
temperatures climbing back into the 30s on Friday. An upper level
disturbance will however pass over the area Friday and Saturday
bringing another possibility of snow for the second half of the
work week lasting into the first half of the weekend.

&&

.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 508 AM MST Sun Dec 4 2016

A cold dry airmass is in place over Eastern Utah and Western
Colorado. This cold dry airmass will support VFR conditions at the
terminals Today. Mid and high level clouds will begin to filter
into Northern Colorado and Northeastern Utah later this evening as
a cold storm system approaches from the north. Generally light
diurnal winds are expected to prevail at the terminals today.

Forecast confidence is high.


&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...Winter Storm Watch from Monday morning through late Tuesday
     night for COZ004-010-012-013.

UT...None.
&&

$$

UPDATE...MDA
SHORT TERM...Larry
LONG TERM...Larry
AVIATION...Larry



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