Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 171039

Area Forecast Discussion
National Weather Service Grand Junction CO
339 AM MST Tue Jan 17 2017

.SHORT TERM...(Today through Wednesday)
Issued at 315 AM MST Tue Jan 17 2017

Mostly clear skies are being reported across the forecast area
tonight as an area of high pressure begins to build over the Great
Basin and Intermountain West. Under these mostly clear skies
temperatures have fallen into the upper teens to mid 20s in the
Grand Valley with single digits in the upper and lower Yampa River
basins. Temperature dew point depressions are running between 2 to
3 degrees, indicating a relatively moist environment. With the
clear skies allowing abundant radiative cooling combined with the
tight temperature dew point depressions can`t rule out patchy fog
around the area this morning. In fact Telluride and Durango
Airports are already reporting reduced visibility due to fog.

Looks like dry weather today and Wednesday with seasonally mild
afternoon temperatures as a ridge of high pressure briefly resides
over the forecast area. Night time temperatures will be chilly
once again tonight and Wednesday night with mostly clear to partly
cloudy skies allowing for radiational cooling and a potential for
early morning fog.

.LONG TERM...(Wednesday night through Monday)
Issued at 315 AM MST Tue Jan 17 2017

Expect clouds to slowly diminish Wednesday night as the closed low
over the Panhandle of Texas moves east. The first in a series of
Pacific storm systems will start to impact the Great Basin by
Wednesday night and early Thursday as southwest winds increase over
the region, especially over the higher terrain. Timing for the onset
of precipitation is a bit tricky, with the GFS and the EC trending a
tad slower than the NAM. A compromised solution brings shower
activity into eastern Utah by Thursday afternoon and across the
remainder of western Colorado by Thursday night. Expect rain or a
rain/snow mix at the onset at valley locations, especially below
6500 feet, but any rain should change over to snow during the
evening hours as colder air moves east across the forecast area.
There looks to be a lull sometime on Friday, but expect it to be
short-lived with another lobe of energy forecasted to move through
late Friday into early Sunday. A transient short-wave ridge will
move across the Intermountain West on Sunday with another wave of
energy moving through the area late Sunday into Tuesday.

Timing and confidence regarding the fine-scale details of these
storms systems late Thursday into early next week remains low at
this time. However, confidence is increasing that significant
accumulations are possible over mountain locations by early next
week. The best focus at this time, for the first two waves through
early Sunday, appears to favor southwest-facing slopes over the
southern and central mountains, with less confidence across the
north. In addition, lower elevation areas, such as the southern
valleys of western Colorado and eastern Utah have the possibility of
receiving significant accumulations as well. Stay tuned to
subsequent forecasts for the latest updates.


.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 315 AM MST Tue Jan 17 2017

Mostly clear skies are being reported across the forecast area
this morning as a ridge of high pressure builds over Eastern Utah
and Western Colorado. Dewpoint depressions are pretty tight so
reduced visibility will be a threat this morning at many
terminals. For the most part expect VFR today with LIFR conditions
possible as visibility becomes reduced due to fog.




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