Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 252046
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
146 PM MST Tue Feb 25 2020

.SHORT TERM...(Tonight through Wednesday night)
Issued at 132 PM MST Tue Feb 25 2020

As expected, snow is slowly coming to an end as the low pressure
and wraparound flow continue to shift eastward. Webcams do show
snow continuing over Rabbit Ears Pass and the higher elevations
along the Continental Divide. A rather persistent band of snow
also formed over the San Juans and kept some snow going for the
Telluride area but the banding is becoming a bit more disorganized
so some light snow will be possible over the next few hours but
nothing of much significance. Even though the low has shifted well
to the east, the surface pressure gradient remains tight and is
causing some gusty winds across the region. Gusts as high as 35
mph have been reported from Cortez up into Nucla, Delta, Montrose,
and Grand Junction. The winds, with the unseasonably cold air,
have made for a cool afternoon to say the least. Unfortunately,
this will translate into a bitter overnight as winds will decouple
and clouds dissipate allowing strong radiational cooling to kick
in. Low temperatures will be anywhere from 10 to 20 degrees below
normal especially in the lower valleys (Gunnison and Craig).

For tomorrow, high pressure starts to build in. A weak, minor
wiggle in the northwesterly flow might bring a few snowshowers to
the Park Range but minimal accumulations expected. Outside of that
area, expect some high clouds in the afternoon but we`ll still see
plenty of sunshine while temperatures will remain on the cool
side. Forecast soundings do show midlevels warming up but
inversions will remain in place keeping the warm air from mixing
to the surface. High temps may be a few degrees warmer than today
but still, cool for this time of year.

.LONG TERM...(Thursday through Tuesday)
Issued at 132 PM MST Tue Feb 25 2020

The inversions that remained in place the last few days will finally
break on Thursday allowing surface temperatures to start rising. MOS
guidance suggesting a bump of 10 to 12 degrees for high temperatures
across the CWA..it`s about time! On the synoptic scale, high
pressure will continue to build in from the west while a deep closed
low affects the New England states. Between these two systems, it`s
fairly quiet though a few minor waves will move through the
northwesterly flow.  One of these waves will bring some light snow
to the northern mountains (and to a lesser extent the central
mountains) during the day Thursday but as the wave is moisture-
starved...minimal snow amounts are expected. Current thinking about
1 to 3 inches, maybe a bit more for the highest elevations. For now,
not looking like any highlights necessary but will keep an eye on
things to see if QPF starts increasing.

Once the snow ends, heights continue to increase as does surface
temperatures. Friday through Sunday, high temperatures look to reach
above normal for this time of year by about 5 degrees or so.  Get
out there and enjoy the weekend before the next system moves in. As
expected, model solutions have changed with the evolution of a
system dropping down from the northwest. Initially, a closed low
forms over the western Canadian provinces Saturday evening and then
splits. The split causes a trough to drop down the West Coast before
closing off a low pressure just off the coast. The timing has
changed and also the location of the trough and eventual closed
low. It`s more semantics though because the end result is some
light QPF over the CWA Sunday (favoring the higher terrain) before
a deformation zone moves through on Monday bringing a better
chance for precip. Another wave is then poised to move through
bringing another shot of QPF to the region Tuesday. All that being
said, there are plenty of details for the medium and long range
models to figure out before confidence really increases in snow
amounts and any associated impacts.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1048 AM MST Tue Feb 25 2020

Lingering moisture in the northerly flow aloft on backside of
upper level trough moving east across KS today will keep streaks
of cumulus near or just below ILS breakpoints for favored upslope
regions across western CO along with scattered snow showers. Gusty
north to northwest winds will also be common...strongest in
the downslope regions south of the San Juan mountains. VFR
conditions are expected elsewhere and will become widespread after
00Z along with a decreasing wind.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...None.
UT...None.
&&

$$

SHORT TERM...TGR
LONG TERM...TGR
AVIATION...BM


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