Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 232140 AAA

Area Forecast Discussion...UPDATED
National Weather Service GRAND JUNCTION CO
240 PM MST Thu Nov 23 2017

.SHORT TERM...(Tonight through Friday night)
Issued at 235 PM MST Thu Nov 23 2017

It`s a beautiful Thanksgiving Day across eastern Utah and western
Colorado today with only some scattered high- and mid-level clouds
streaming across the skies. Temperatures have been on the rise
this afternoon and, while no record highs have been met or
exceeded yet as of 2:00 PM MST, it`s certainly still a
possibility, especially in some of the central and southern valley

Looking at the synoptic overview, the ridge of high pressure
situated overhead will flatten this evening as a quick moving
shortwave trough and weak cold front drop into the area in the
northwesterly flow. This disturbance will generally just see an
increase in mid-level clouds tonight and on Friday with some
light snow showers developing over the northern and central
Colorado mountains late Friday morning. The increase in clouds
overnight will keep low temperatures mild for this time of
year...about 10 degrees above normal. The aforementioned snow
showers will bring minimal accumulations and no impacts since the
majority of snow will fall above 10kft as snow levels remain high
and most activity will end Friday evening. 700mb temperatures will
briefly drop to between 0 and -2 degrees C across areas north of
I-70 behind the front so temperatures on Friday should cool down
some 5 degrees or so. Skies will generally be clear across the
region late Friday for a chillier, albeit still mild for this time
of year, night.

.LONG TERM...(Saturday through Thursday)
Issued at 235 PM MST Thu Nov 23 2017

A ridge of high pressure will begin to amplify over the region by
daybreak Saturday and continuing into Sunday for a dry and mild
weekend with mostly to partly sunny skies and typical diurnal wind
shifts. Upper level flow turns to the southwest late Sunday as a
Pacific trough approaches the border of the western CONUS. Models
are beginning to come in better agreement with one another in
regards to the structure of this storm, but significant
inconsistencies still exist, especially in regards to timing. The
GFS is a good 6 to 12 hours quicker than the EC in bringing the
trough and associated cold front into our forecast area, and
almost 24 hours quicker in moving the storm out of the area! The
GFS brings a closed low into our region from the northern Great
Basin Monday evening while the EC favors a slower and slightly
more southern track into our area beginning Tuesday morning and
exiting Wednesday morning. So while confidence is increasing in a
shift towards cooler and wetter conditions early next week, would
still like to see some better and more consistent model agreement.

After the departure of this system at or around mid next week,
drier conditions look to return to the region before extended
models once again diverge on the synoptic pattern.


.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 200 PM MST Thu Nov 23 2017

A few high clouds above the forecast area will continue in
northwest flow aloft. Winds will be light and terrain driven.
A ridge of high pressure over the desert southwest will keep VFR
conditions over the area through the period.




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