Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 161026

Area Forecast Discussion
National Weather Service Grand Junction CO
326 AM MST Mon Jan 16 2017

.SHORT TERM...(Today through Wednesday)
Issued at 253 AM MST Mon Jan 16 2017

It`s been a long week for eastern Utah and western Colorado with
snowfall that has lasted for the last several days. And it still
doesn`t want to let go. Wraparound flow from the closed low, that
is currently over northern Texas/western Oklahoma, is still
drawing in enough moisture and getting enough lift to make it over
the mountains and cause snowfall. Montrose, Gunnison, Pagosa
Springs, and the San Juans continue to see snowfall at this hour
though amounts look to be on the order of an inch or less. This,
according to SNOTEL data and ASOS reports from the airports. Will
keep an eye on the Gunnison area, in particular, to see if the snow
warrants a quick morning advisory. Models keep this light snowfall
in the forecast for southeastern portions of the CWA for much of
the day with conditions slowly improving from northwest to
southeast. Previous grids captured this trend well so made minor
adjustments to going grids. Satellite and obs also show some fog
across the area but nothing too low just yet. Again, will keep an
eye on the usual spots and issue dense fog advisories as the need
arises. For now, the northern valleys and southeastern Utah
valleys are the closest to 1/4 mile visibilities. Outside of the
above mentioned areas, no precipitation expected with variable
cloudiness. Less clouds to the northwest and more the closer you
get to the mountains. Temperatures will hover right about near

Tuesday, the snow finally ends as a ridge of high pressure builds
into the area. Most models do show a small area of circulation
forming over Arizona early Tuesday morning and actually closing
off forming a weak upper level low. The difference? The GFS and
Canadian put some showers over the San Juans while the NAM and EC
keep us dry. Following the NAM at the moment and no mention of
precipitation is in the forecast Tuesday into Wednesday. Will be
interesting to see which models win out. Either way, areas north
of the San Juans should finally see the sun return. Unfortunately,
it`ll take a bit longer for the San Juans and southern valleys to
clear out which should occur Tuesday evening into Wednesday
morning. Some minor cold air advection will drop high temperatures
a few degrees Tuesday but nothing out of the ordinary.

Wednesday, ridging continues to build in ahead of the next system
to affect the area. Expect plenty of sun and warmer temperatures
than Tuesday. Enjoy it as another active weather pattern looks to
be on the horizon.

.LONG TERM...(Wednesday through Sunday)
Issued at 403 PM MST Sun Jan 15 2017

Confidence in onset of showers not great on Thursday as ECMWF and
GFS a bit out of step. 12Z/EC was a bit shallower and more
progressive with the West Coast trough thereby generating the
first chances for precipitation across eastern Utah in the
morning, then portions of western Colorado during the afternoon.
GFS ensembles showing less than confidence inspiring spread and
CMC similar to EC solution. inclined to bring
snowfall chances for the mountains earlier than indicated by GFS.

Regardless of timing issues, models all indicated the trough will
bring rain and snow to the area through Friday. Another trough
ejecting from a closed low off the coast of British Columbia is
set to generate more unsettled conditions this weekend. Given
model spread, hesitate to mention snowfall amounts, snow levels
and other details at this point.

Temperatures are forecast to hover near or a little above normal
through the period.


.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 253 AM MST Mon Jan 16 2017

Snow and fog are being reported across much of the forecast area
this morning. MVFR to IFR conditions are being reported at most
TAF sites to include KMTJ, KEGE, KASE, KTEX, and KVEL. Mountain
TAF sites KEGE, KASE, and KTEX will likely fluctuate through IFR
to VFR conditions today as snowshowers persist across the central
mountains and San Juans. Those areas affected by fog should see
conditions improve after 17Z. Another chance for fog exists
tonight but do not anticipate it to be too widespread. Towards the
end of the the TAF period, conditions will slowly start improving
as moisture and showers come to an end.




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