Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 262140
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
Issued by National Weather Service Salt Lake City UT
340 PM MDT Wed Apr 26 2017

.SHORT TERM...(Tonight through Thursday night)
Issued at 330 PM MDT Wed Apr 26 2017

Satellite and radar this afternoon show scattered orographic
showers this afternoon under northwest flow aloft, generally
limited to the central and northern ranges of Colorado. Webcams
show snow falling at a few high elevation locations, most notably
Rabbit Ears Pass along US-40, though roads are only wet.

Moisture increases tonight ahead of a fast-moving shortwave
trough approaching the area from the northwest. Deepening
moisture, combined with dynamic forcing at mid and higher levels
of the atmosphere is expected to result in widespread snow across
all mountain areas. Snow levels will lower to mountain bases in
the north, though accumulations will be limited in the lower
elevations.

A cold front associated with this system sweeps southeastward
across much of the forecast area late tonight through Thursday
morning. Moisture decreases behind the front, especially across
the south, but still sufficient to produce steady snow in the
northern and central mountains. Shower activity will be more
scattered over the southern ranges. Despite less available
moisture, expect showers will continue into Thursday night as a
broad trough settles over the region. A few weak thunderstorms
are possible as well as a colder and more unstable air mass moves
into the region.

Clouds, showers and weak cold air advection will keep afternoon
temperatures well below normal. Overnight lows will be cold, but
expect clouds and moisture should prevent temperatures from
reaching freezing in the lower valleys.

This late-season snow potential is well-handled by the current
headlines. The northernmost Colorado ranges may see more than a
foot in some areas. Lesser amounts are expected in Colorado`s
central mountains.

.LONG TERM...(Friday through Wednesday)
Issued at 441 AM MDT Wed Apr 26 2017

Off the west coast, a well-amplified ridge begins to set up for
the latter half of the week. This will push yet another upper
level trough into our forecast area Friday and into Saturday with
extended models even carving out a cutoff low. Details still need
to be worked out with this storm and would definitely prefer to
see some more model consistency. Regardless, the cool, unsettled
weather will continue through at least the end of the work week.
Temperatures will remain below normal through the week and
overnight lows will approach or reach freezing in many valley
locations.

Going even further into the extended, northwesterly flow appears
to set up over the region on Sunday. This will bring a shift
towards drier conditions although lingering moisture will more
than likely keep showers going over the northern mountains into
early next week.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 330 PM MDT Wed Apr 26 2017

Scattered rain and snow showers over the area will become
numerous to widespread beginning this evening as a storm system
moves through the region. The precipitation will resulted in
lowered cigs and some reduced visibilities, with mountains
frequently becoming obscured. Drier air moving in from the west
will allow precipitation to taper off from west to east during the
early morning hours, though some showers will linger at higher
elevation sites. Cigs will drop below ILS breakpoints at most TAF
sites, with periods of MVFR/IFR conditions occurring at higher
elevation TAF sites such as KTEX and KASE in snow.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...Winter Weather Advisory from 6 PM this evening to 6 PM MDT
     Thursday for COZ009-012.

     Winter Storm Warning from 6 PM this evening to midnight MDT
     Thursday night for COZ004-013.

     Winter Weather Advisory from 6 PM this evening to midnight MDT
     Thursday night for COZ010.

UT...None.
&&

$$

SHORT TERM...NL/DVC
LONG TERM...MMS
AVIATION...MT


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