Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 230648
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
1148 PM MST Fri Feb 22 2019

.UPDATE...
Issued at 1144 PM MST Fri Feb 22 2019

Some snow is continuing at this hour across the central mountains
and a few spots in the San Juans although can`t see any sign of a
gorge event yet. Satellite imagery shows the best enhancement over
the Front Range though there is some along our portions of the
Continental Divide. Figure another 3 hours or so for the
highlights and then we`ll call it good. So...current highlights
will now expire at 3AM. Rest of forecast looks good.

UPDATE Issued at 524 PM MST Fri Feb 22 2019

Updated to let the Winter Storm Warnings for the southwest
Colorado valleys, southwest San Juans, Uncompahgre Plateau and La
Sals and Abajos expire at 5 pm. While some snow showers are
continuing over these areas, additional accumulations are expected
to remain light through the rest of this evening with focus
shifting to the central Colorado mountains and northwest San Juans
as the flow shifts to north-northwest this evening. The best
dynamics appear to be shifting into the central mountains along
the divide. A Winter Storm Warning remains in effect for
northwest San Juans with a Winter Weather Advisory in effect
across the central Colorado mountains through midnight tonight,
with these areas favored for additional significant accumulations
and impacts. Vail Pass and the Uncompahgre Gorge in the northwest
San Juans will have to be watched closely as these areas could
continue to snow past midnight into early Saturday morning.

&&

.SHORT TERM...(Tonight through Saturday night)
Issued at 352 PM MST Fri Feb 22 2019

A broad swath of snow continued to fall across western Colorado
this afternoon ahead of the deep mid-level trough which pummeled
some areas in eastern Utah and western Colorado with excessive
snowfall over the past few days. The trough axis was aligned with
the Wasatch mountains of eastern Utah at midafternoon placing
best lift associated with the system over western Colorado. A few
showers lingered over the eastern Utah high country, but expect
that activity will diminish by evening.

The trough-axis will shift over western Colorado this evening then
push east of the Continental Divide after midnight. As this occurs
winds will shift to the west on the backside of the trough axis
then northwest as the trough pushes farther east. Instability and
orographic flow is expected to keep wringing snow from the
lingering moisture across the central Colorado mountains. In
additional, models were pretty clear on the potential for heavier
snow in the Uncompahgre Gorge with the northwest flow. Therefore,
decided to extend the Winter Weather Advisories over the central
Colorado mountains and the Winter Storm Warning for the northwest
San Juan Mountains until midnight. Elsewhere, the loss of dynamic
lift will allow snow to finally wind down and with that in mind,
will allow remaining highlights to expire at 5 PM MST.

Some light snow will linger along the Continental Divide overnight,
but additional accumulations will be light. Overnight lows be
colder tonight with areas of fog forming in the Grand Flat in
east-central Utah where skies will be clearing. Drier northwest
flow will result in dry weather for most areas, though a weak,
fast moving disturbance may bring some light snow showers to the
northern mountains, mainly during the afternoon and continuing
into Saturday night. Despite below normal temperatures, snowmelt
during the day on Saturday is expected to result in more fog
across the valleys on Saturday night.

.LONG TERM...(Sunday through Friday)
Issued at 352 PM MST Fri Feb 22 2019

Previous forecast discussion appears to hold for the latter part
of the weekend through the week ahead. A largely dry zonal flow
will allow temperatures to moderate toward normal with occasional
weak disturbances bringing light snow showers to the northern
mountains. Accumulations will be light with this activity and
clouds will be variable with mid and high level cloud cover,
mainly north of I-70, with mostly to partly sunny skies to the
south. GFS now hinting at a more impactful shortwave in northwest
flow to impact the area Friday, but ECMWF and Canadian had less
energetic solutions.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1112 PM MST Fri Feb 22 2019

Periodic IFR/MVFR conditions can be expected through 10Z as
scattered snow showers persist across western Colorado.
Significantly drier air has already pushed into eastern Utah in
the wake of the trough this evening and this drier air will
continue to progress east overnight. As a result, snow showers
will taper off across all but the Continental Divide through
approximately 12Z Saturday morning. VFR conditions and clearing
skies will make an appearance from west to east by 15Z Saturday
with VFR across all TAF sites. An exception will be over the
Elkhead Mountains where some light, isolated snow showers may
redevelop after 20Z.


&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...Winter Weather Advisory until 3 AM MST Saturday for COZ009-010-
     012.

     Winter Storm Warning until 3 AM MST Saturday for COZ018.

UT...None.
&&

$$

UPDATE...TGR
SHORT TERM...NL
LONG TERM...NL
AVIATION...TGJT


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