Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 202344

Area Forecast Discussion
National Weather Service GRAND JUNCTION CO
444 PM MST Tue Feb 20 2018

.SHORT TERM...(Tonight through Thursday)
Issued at 154 PM MST Tue Feb 20 2018

Convective instability leading to scattered snow showers across
the region this afternoon, focused mainly across the central
portions of the forecast area. Spotty accumulations around an inch
or two have occurred so far and activity will be diminishing this
evening as the sun goes down. Expect clearing and cold conditions
across the region tonight with temperatures dropping below zero
again across our higher valleys.

Wednesday will be another transition day with mainly dry
conditions expected in southwest flow. Mid and high level moisture
will be increasing throughout the day with dense cloud cover
anticipated by late afternoon. Few flurries or light snow showers
possible over the peaks, but nothing significant. Models are in
good agreement with driving a strengthening wave northeastward
across the Four Corners Wednesday night and Thursday. RER of 120
kt H3 jet sets up near the Southwest San Juans. Surge of low level
moisture combined with favorable jet dynamics and south to
southwesterly H7 flow will drive another round of moderate to
potentially heavy snowfall into the southwest San Juans and into
the Pagosa Springs area. Gradient looks fairly tight between
Durango and Pagosa with 3 to 6 inches possible east of Bayfield
with number falling off below 3 inches to the west. Any shifting
around of the flow or final placement of the upper level jet will
adjust final output and for now will be going with advisory level
snowfall. Snow lingers through midday Thursday before shutting
down as we wait for the next system that is now targeting a Friday

Cold temperatures will moderate slightly over the next 24 hours,
although readings will remain on the cooler side of normal.

.LONG TERM...(Thursday night through Tuesday)
Issued at 154 PM MST Tue Feb 20 2018

Active weather will continue through this extended period with the
models loading up on another two systems that will be driving
through. The EC and GFS are driving another strong jet through the
area Friday with deep southwest flow lifting up and over the
southwestern mountains. Approaching longwave trough and cold
advection will bring more snow to the region. Trough axis with
this wave is expected to move through Friday night with showers
lingering through Saturday morning. Flow then swings back to the
northwest with another fast moving Pacific wave expected to roll
through Sunday and Sunday night. Expect things to dry out and calm
down just a bit Monday and Tuesday, but more energy will be
filling out another trough across the western U.S. that will bring
more snow to the area by midweek. Temperatures are expected to run
around 5 degrees below normal each day.


.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 444 PM MST Tue Feb 20 2018

A few stray showers this evening will pass through and impact
KASE, KMTJ, and potentially KTEX, KEGE, and KRIL through about
02z. Showers are expected to taper off after this time. Some low-lying
stratus will be possible tonight where it has recently snowed, but
hard to pinpoint exactly where at this time. Cigs will improve
other than the spotty stratus tonight, before they begin to drop
again after 18z on Wednesday with an incoming mid level cloud deck.


CO...Winter Weather Advisory from 8 PM Wednesday to 6 PM MST Thursday
     for COZ019-023.



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