Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 261624
AFDGJT

Area Forecast Discussion
National Weather Service GRAND JUNCTION CO
1024 AM MDT Wed Apr 26 2017

.SHORT TERM...(Today through Thursday)
Issued at 441 AM MDT Wed Apr 26 2017

Residual moisture, instability and orographics are expected to
continue to bring scattered snow showers to the mountains this
morning with coverage increasing during the afternoon. The
northern and central ranges are favored today.

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 the region 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.

Clouds, showers and weak cold air advection will keep afternoon
temperatures well below normal today, and even more so Thursday in
the wake of the cold front mentioned previously. Overnight lows
will be cold, but expect clouds and moisture should prevent
temperatures from reaching freezing in the lower valleys.

Given persistent late season snowfall expected tonight through
Thursday night, will hoist winter weather highlights with this
package. The northernmost Colorado ranges may see more than a foot
in some areas, so opted to upgrade the watch to a warning for the
Elkhead, Park and Flat Tops beginning this evening and continuing
through Thursday evening. Lesser amounts expected in Colorado`s
central mountains so opted for advisories for those areas tonight
through Thursday afternoon.

.LONG TERM...(Thursday night through Tuesday)
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 1024 AM MDT Wed Apr 26 2017

Scattered rain and snow showers will develop this afternoon and
become numerous to widespread this evening as a storm impacts the
region. Showers will frequently lower CIGs and VIS with mountains
frequently becoming obscured. By 12Z showers will gradually taper
off from west to east as dry air moves in from the west. Coverage
will begin to shift to along the divide after 18Z Thursday. CIGs
will drop below ILS breakpoints at most TAF sites and periods of
MVFR and even brief IFR conditions are possible especially at
sites such as KTEX and KASE.

&&

.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
LONG TERM...MMS
AVIATION...TGJT



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