Area Forecast Discussion
Issued by NWS Grand Junction, CO

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000
FXUS65 KGJT 111109
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
409 AM MST Wed Jan 11 2017

.SHORT TERM...(Today through Thursday)
Issued at 340 AM MST Wed Jan 11 2017

The moist and near zonal flow over the area will continue
producing mountains snowfall through Thursday, with a mix of
precipitation type at lower elevations. The first minor trough
that will enhance the snowfall will move over the area about
mid-morning. This feature may be associated with a jet speed
maxima visible on WV Sat over SW UT this morning. Then another
wave, which satellite imagery shows over Nevada early this
morning, will move across the area late this afternoon and
evening. Neither feature is all that strong and moisture doesn`t
increase significantly, so believe the current winter wx products
should handle it well, though have added CO zone 14, Gunnision
vicinity, to the advisories after a call to county dispatch
reported an inch new tonight with 3+ inches likely by Thursday
morning. Decided to leave zone 8 and the Eagle vicinity out of the
winter products as temps are a bit warm this morning causing
precip to vary between rain and snow.

.LONG TERM...(Thursday night through Tuesday)
Issued at 331 PM MST Tue Jan 10 2017

The current satellite water vapor image is showing a trough of low
pressure pushing into the West Coast with another storm system
centered approximately 950 miles off of the Oregon coast. In
addition the satellite and GPS derived total blended precipitable
water image is showing yet another atmospheric river pushing into
the west coast. Precipitable water values associated with this
atmospheric river over the Eastern Pacific and California coast
are ranging between 1.1 and 1.3 inches, which is substantial.

The 1200Z ECMWF and GFS20 have initialized well with the these
synoptic weather features and remain in good agreement through
next Tuesday. Both of these forecast models show the trough of low
pressure pushing into the west coast interacting with the
atmospheric river resulting in another round of snow tonight into
Thursday morning. A short break in the winter weather action is
anticipated Wednesday morning before the second storm system
pushes into California steering yet more moisture into our area
resulting in a reinforcing shot of snow Thursday afternoon into
Saturday. Most likely this second shot of heavy snow will bring
snow to the lower elevations than tonight`s system.

The latest model runs are showing this storm system moving down
the California coast into Mexico by Saturday. This scenario will
place southern portions of our CWA in wrap flow resulting in
additional snow for the San Juans on Saturday and Sunday. Please
be sure to monitor the forecast for frequent updates as this storm
system unfolds.

&&

.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 340 AM MST Wed Jan 11 2017

Winter weather will continue across the area for the next 24
hours. Mountains will remain obscured and except for KCNY and
KDRO, TAF sites will experience periods of snow, rain and snow at
lower airports, which will bring CIGS below ILS breakpoints while
also limiting VSBY to MVFR, and brief IFR levels through much of
the period.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...Winter Weather Advisory until midnight MST tonight for
     COZ001>003-017>019.

     Winter Weather Advisory until 9 AM MST Thursday for COZ005-014.

     Winter Storm Warning until 9 AM MST Thursday for COZ004-009-010-
     012-013.

UT...Winter Weather Advisory until midnight MST tonight for UTZ023-
     025-028.

&&

$$

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



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