Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 170541

Area Forecast Discussion
National Weather Service Grand Junction CO
1041 PM MST Thu Feb 16 2017

.SHORT TERM...(Tonight through Friday night)
Issued at 340 PM MST Thu Feb 16 2017

Current satellite indicates a very weak disturbance bringing high
clouds to Utah, with the cloud front just west of the UT/CO border
as seen from WFO Grand Junction as I type. ASOSs in Utah do not
indicate clouds any lower than 12kft at this time, so not expecting
ceilings to drop much lower than that tonight with this passing
disturbance. The closed low bringing heavy rains to California on
Friday will tighten the pressure gradient between high pressure in
place and the incoming trough. The closed low over California will
increase moisture from the southwest on Friday with showers expected
to begin over the mountains late Friday afternoon. Good model
agreement on southwest facing slopes receiving rain and/or snow
Friday evening through the overnight hours into early Saturday

.LONG TERM...(Saturday through Thursday)
Issued at 340 PM MST Thu Feb 16 2017

The closed low over California will split into an elongated trough
on Saturday as it pushes eastward toward Utah and Colorado. At
this point, forecast models indicate this trough holding together
structure wise but losing some of its oomph and moisture as it
passes through the mountains in Nevada and Utah Saturday
afternoon. Forecast PoPs are on the low side as thinking between
the southerly flow ahead of this trough will keep activity
orographic and showery, but these may be on the low side. 700mb
temps still remaining between 0C and -3C over the weekend which
will keep the heaviest snow above 10000 ft with some snow as low
as about 8000 ft. The elongated trough eventually makes it to
eastern Utah and western Colorado with the best forcing mechanisms
and moisture on Sunday with its associated cold front. This should
be the big day for precipitation, and will be our biggest impact
day for travel. Snow level on Sunday will likely drop to about
6000 ft by end of day, but by then the trough will have passed and
conditions will begin to stabilize. A break in the weather is
expected Monday through Tuesday before the next possible storm
moving in next Wednesday. Forecast models have flip flopped a bit
from run to run but have been indicating a strong cold front
associated with a closed low passing through the intermountain
west sometime between Wednesday and Thursday.


.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1039 PM MST Thu Feb 16 2017

VFR conditions at all terminals overnight into Friday. High clouds
continue to spread over all terminals Friday. Ceilings lowering
after noon on Friday. BKN to OVC ceilings on Friday early evening
but CIG heights will remain above ILS values until after dark.




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