Area Forecast Discussion
Issued by NWS Grand Junction, CO

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000
FXUS65 KGJT 201747
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
1047 AM MST Fri Jan 20 2017

.SHORT TERM...(Today through Saturday)
Issued at 344 AM MST Fri Jan 20 2017

KGJX Doppler Radar continues to show snow falling across the
forecast area this morning as the first in a series of storm
systems continues to sweep across the forecast area. Short term
forecast models are showing a lingering possibility of snow
showers through late morning with a greater probability focusing
over the Mountains. A lull in the winter weather is anticipated
this afternoon into the early evening hours.

Snowfall rates will pick back up once again initially in
Southeastern Utah and Southwestern Colorado this evening as the
next storm system approaches from the southwest. Snow
probabilities will increase and spread north and east after
midnight Saturday morning as this second portion of the storm
system pushes east. Abundant snowfall is expected over the
mountains with this system in particular southwestern facing
slopes and the San Juan Mountains. Numerous Winter Storm Warnings
and Winter Weather Advisories remain in effect through Saturday
night. Please check the weather forecast before you head out today
and also check road conditons on UDOT and CDOT`s web pages.

Overall the short term forecast confidence is high.

.LONG TERM...(Saturday night through Thursday)
Issued at 344 AM MST Fri Jan 20 2017

The current satellite water vapor image is showing two strong
storm systems impacting the northern hemisphere this morning. The
first is currently positioned off of the British Columbia coast
with a strong jet stream pushing into coastal California. The
second storm system is pushing northeast through the northern
plains. The 0000Z ECMWF and 0600Z GFS20 have initialized well with
these synoptic scale weather features and remain in good agreement
through at least next Tuesday.

Both forecast models are indicating that a ridge of high pressure
will briefly build over the intermountain west on Sunday,
providing another break in the weather for our forecast area.
However, this break will be short lived as the third and stronger
storm system begins to enter Eastern Utah Sunday evening. This
stronger system will have significant upper level jet support
which will result in greater snowfall rates and windier conditions
through Tuesday.

Behind the system on Tuesday the general atmospheric flow over
the forecast area will become west northwesterly. This west
northwesterly flow will shift the focus from the San Juan
mountains to the northern mountains and northwestern facing slopes.
In addition the cold northwesterly flow will also result in much
colder temperatures for the second half of the upcoming week.

Overall the extended forecast confidence is high.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1047 AM MST Fri Jan 20 2017

Scattered light snow showers will continue for many of the
terminals this afternoon with more isolated coverage north of
I-70. Another surge of moisture will infiltrate the area after
06Z, resulting in increased coverage and intensity of showers
through Saturday. The southern mountains will be favored in the
southwesterly storm track. The persistence of showers, plus the
development of fog in valleys overnight, will result in periods
of reduced VIS/CIGS for nearly all TAF sites.

Overall forecast confidence is moderate.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...Winter Weather Advisory until midnight MST Saturday night for
     COZ003-008-014.

     Winter Storm Warning until 5 PM MST Saturday for COZ021>023.

     Winter Storm Warning until 6 AM MST Sunday for COZ009-010-012-
     013.

     Winter Storm Warning until midnight MST Saturday night for
     COZ017-018.

     Winter Storm Warning until 8 PM MST Saturday for COZ019.

     Winter Weather Advisory until 6 AM MST Sunday for COZ004.

UT...Winter Weather Advisory until midnight MST Saturday night for
     UTZ025.

     Winter Storm Warning until 5 PM MST Saturday for UTZ022.

     Winter Weather Advisory until 5 PM MST Saturday for UTZ028.

&&

$$

SHORT TERM...Larry
LONG TERM...Larry
AVIATION...MMS


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