Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 261041

Area Forecast Discussion
National Weather Service GRAND JUNCTION CO
441 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

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

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 06Z TAFS through 06Z Wednesday night)
Issued at 1113 PM MDT Tue Apr 25 2017

Aviation conditions will continue to improve over the next 6
hours. VFR conditions at all but ASE are noted as of 5:30z. Expect
ceilings to rise at all terminals overnight including ASE. Partly
cloudy skies early will become overcast in the afternoon as the
next storm system moves in from the northwest. Ceiling heights
will lower once again on Thursday afternoon with some shower
activity moving in by nightfall. VEL, EGE, and ASE will be the
first to see aviation conditions deteriorate from this storm,
between 0z and 6z Friday.



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.




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