Area Forecast Discussion
Issued by NWS Grand Junction, CO

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000
FXUS65 KGJT 181053
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
353 AM MST Wed Jan 18 2017

.SHORT TERM...(Today through Thursday)
Issued at 351 AM MST Wed Jan 18 2017

Low clouds are impacting portions of the forecast area this
morning. The current GOES Satellite IFR (LOW CLOUD)Probability
image is showing stratus clouds in place over the Uinta Basin,
the Grand Valley and portions of the Upper and Central Yampa River
Basin. In addition low clouds are also present in Durango and
Pagosa Springs this morning. The good news is that the low clouds
will help to suppress the formation of dense fog at these
locations with the exception of Upper and Central Yampa River
Basin where dense fog is currently being reported.

Today should be a pleasant day to get outside with Blue Bird
conditions anticipated at many of the local ski areas. However,
high clouds will start to move in this evening ahead of the first
of a series of three storm systems that are expected to begin to
impact Eastern Utah and Western Colorado on Thursday. This first
storm system will be the weakest of the bunch, but will bring
mountain snow which could be heavy at times and a rain/snow mix to
the Grand Valley. Snow levels will be fairly low with this system
and places where southwest flow is favored such as Durango could
see a couple of inches of snow on Thursday night.

Overall short term forecast confidence is high.

.LONG TERM...(Thursday night through Tuesday)
Issued at 351 AM MST Wed Jan 18 2017

The current satellite water vapor image is showing a trough of low
pressure centered over New Mexico and a storm system pushing into
British Columbia. Additionally, the satellite and GPS derived
total precipitable water image is showing abundant moisture
pushing into Northern California stretching into the Pacific
Northwest. This moisture is representative of an Atmospheric river
that is stretching across the Pacific Ocean. The 0000Z ECMWF,
GFS20 and NAM12 have initialized well with these synoptic weather
features and remain in good agreement through the forecast period.

Both of the longer range models (the ECMWF and GFS20) indicate
that the first in a series of storm systems will begin to impact
the area on Thursday. As previously mentioned this storm system
will bring mountain snows and a rain/snow mix for the Grand
Valley. This system exits the area on Friday before the next storm
system quickly arrives Friday night into Saturday. These first two
storm systems will bring advisory level snow to a majority of the
mountain zones and up to 2 inches of snow to the low elevation
valley zones. There will be more than enough snow to cause some
impact to travel, especially over the Mountain Passes.

Yet another storm system will push into the area beginning Sunday
night persisting into Tuesday. At this point this system is to far
out to get exact snowfall totals, but it does look to be a more
robust system with plenty of upper level jet support which the
first two systems are lacking. In addition both the upper level
low and surface low will pass over the forecast area with this
third storm system. The take home message is that a series of
storm systems will pass over the forecast area beginning Thursday
bringing winter weather to Eastern Utah and Western Colorado
through the first half of next week. Although, initial snowfall
amounts will be relatively small, these three storm systems
collectively will bring abundant snowfall to the area, resulting
in significant impacts to travel. Please keep a close eye on the
forecast and check with CDOT and UDOT for the latest road
conditions before you decide to travel during this period of time.

Overall long term forecast confidence is moderate to high.

&&

.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 251 AM MST Wed Jan 18 2017

Stratus is being reported at many of the terminals this morning,
especially those located in the Grand Valley. Periodic dense fog
is also being reported in the Upper and Central Yampa basins as
well as in the vicinity of both Durango and Telluride. Overall the
forecast is calling for MVFR conditions improving to VFR by this
afternoon. Winds are anticipated to be generally light and
diurnally driven through the next 24 hours.

Overall forecast confidence is high.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...Dense Fog Advisory until 11 AM MST this morning for COZ002-005.

UT...None.
&&

$$

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



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