Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 201045

Area Forecast Discussion
National Weather Service Grand Junction CO
345 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 12Z TAFS through 12Z Saturday morning)
Issued at 344 AM MST Fri Jan 20 2017

KGJX doppler radar continues to show snow showers around the
forecast area this morning, especially over the mountainous
terrain. Light snow continues to be reported at a majority of the
terminals as well with generally VFR cigs and IFR vis. GOES IFR
satellite derived IFR probability is indicating IFR to LIFR
conditions in the Grand Valley and also in the vicinity of Cortez
and Durango. Reduce vis will be possible through roughly 9:00 am
MST in these locations but should improve by mid morning with VFR
then prevailing through this afternoon. The second wave of a
multi-day storm will begin to impact the terminals Friday night
persisting through Saturday.

Overall forecast confidence is moderate to high.


CO...Winter Weather Advisory until midnight MST Saturday night for

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

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

     Winter Storm Warning until midnight MST Saturday night for

     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

     Winter Storm Warning until 5 PM MST Saturday for UTZ022.

     Winter Weather Advisory until 5 PM MST Saturday for UTZ028.



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