Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 172325

Area Forecast Discussion
National Weather Service GRAND JUNCTION CO
425 PM MST Wed Jan 17 2018

.SHORT TERM...(Tonight through Thursday night)
Issued at 325 PM MST Wed Jan 17 2018

Not much to speak of today, weather-wise, as the remnants of a
weak upper level trough exit our area and transitory high pressure
builds in. Temperatures continue to run warm and will do so
through Friday as the next system approaches. The upper level
trough and cold front remain off the Pacific coast though the
upper level jet is moving into Washington and Oregon bringing
plenty of clouds with it. These clouds will start migrating into
our area after midnight tonight with most of the forecast area
seeing variable clouds by noon Thursday. No precipitation expected
Thursday as temperatures remain about the same as seen today.

.LONG TERM...(Friday through Wednesday)
Issued at 325 PM MST Wed Jan 17 2018

The trough and cold front, supported by a 120+ kt jet stream,
will be bringing precip to Nevada and Idaho Friday morning. We`ll
see clouds on the increase as well as some gustier winds
materialize thanks to a tightening pressure gradient. A few timing
differences have cropped up in models, slowing them down a bit,
and the latest GFS also lowers QPF some...again, not by too much.
Southwest flow will still bring in much warmer air ahead of the
front with 50s looking more and more likely for the valleys.
Precip should start over the eastern Uintas Friday evening with
more widespread precip starting over the Colorado mountains by
daybreak Saturday. Specific humidity, an indication of available
moisture, remains above average so the system should have plenty
to work with. H7 temps still look in the -3C to -5C range
depending on the mountain range and this is at the start of the
event. Heaviest snowfall looks to occur from noon Saturday through
Saturday evening, not the best time of day (night is always
better), and noticeably cooler air will quickly move in once the
front moves through. Snow amounts, for now, look to be in the 6 to
12 inch range with some spots seeing higher amounts.

Sunday morning the much colder air aloft will allow some
instability showers to kick off over much of the forecast area
though significant accumulations are not anticipated. These
showers will continue off and on through the day and finally
ending by Monday. This will be short-lived though as pieces of
energy will move over Colorado and utah bringing more showery
type precip to the mountains. Previous runs showed some good
snowfall potential but latest runs have backed off considerably.
Despite that, the unsettled weather will continue through Tuesday


.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 425 PM MST Wed Jan 17 2018

No impacts to airport operations anticipated through the next 24
hours as a ridge of high pressure dominates the west. VFR
conditions will prevail with CIGS above ILS breakpoints during the
entire period.






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