Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 270601

Area Forecast Discussion
National Weather Service Grand Junction CO
1101 PM MST Sun Feb 26 2017

.SHORT TERM...(Tonight through Monday night)
Issued at 351 PM MST Sun Feb 26 2017

A low pressure system moving onshore the Pacific Northwest this
morning will drop south and eastward as it becomes an open trough.
This system is going to bring strong winds to the mountains and
marginally deep moisture to southwest Colorado. Upper level
support will develop on the south end of the trough pulling a
sliver of subtropical moisture in from Baja California/SoCal then
substantially strengthen as it nudges into southern Utah and
southwestern Colorado. The moisture will weaken as it gets pinched
down by drier air to the north, but this will likely create a set
up for heavy wet snow across southwest Colorado. Southwest flow
ahead of the cold front associated with this system will warm up
conditions Monday afternoon before cooler air sags into eastern
Utah Monday afternoon and western Colorado Monday night...however
the H3 jet strengthens further to nearly 160 kt over east central
Utah and west central Colorado during this same timeframe so
conditions will also be quite breezy. The jet then weakens and
moves northeastward over the Flattops and Park/Gore Ranges Monday
night. The big takeaway from this is that conditions are going to
be very windy in the mountains as this jet moves through the
region and very heavy rates of snow are possible Monday night
across the southern San Juans and Four Corners to Wolf Creek Pass
corridor. Was confident enough to issue a winter storm watch for
the Animas valley and Hwy 160 corridor to Pagosa Springs. The
latest GFS run puts the heaviest band of moisture south of the
state border in NM, but the NAM, EC, and SREF favor the CO portion
of the Four Corners. With nighttime timing, precipitation will
likely be very wet heavy snow.

As far as locations in northcentral Colorado, am expecting those
winds to really pick up over the Grand Mesa, Flattops and then
eventually the Park and Gore Range. The cold front will shift
winds to northwesterly Monday evening which will be favorable for
the Steamboat area and surrounding mountains. At this time, the
town of Steamboat and locations west toward Craig and the Utah
border look sub-advisory but these areas will see some minor to
moderate impacts at times with H7 temps quite chilly and in the
efficient dendritic growth zone. The moisture is lacking a bit up
north compared to the Four Corners snow threat, but some snow will
occur due to the lower density orographic snow possibilities.

Lower valleys along the I-70 corridor may see
some snowflakes, but no majors concerns at this time along the
major thoroughfare expect for the advised area east of Edwards.

.LONG TERM...(Tuesday through Sunday)
Issued at 351 PM MST Sun Feb 26 2017

Snow across southwestern Colorado will continue into the rush hour
period Tuesday morning with possible showers throughout the day
Tuesday. The GFS is off from all of the other available forecast
models in trying to dry conditions out Tuesday morning for a bit. A
secondary 500mb trough/cold front is progged to pass through Tuesday
late afternoon bringing additional snow across eastern Utah and
western Colorado. Chilly conditions will develop behind this
second cold front Tuesday through Wednesday before more seasonable
temperatures return Thursday. Next Friday and Saturday will be
sunny and dry across Utah and Colorado, with the next weather
maker possible Sunday.


.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1102 PM MST Sun Feb 26 2017

VFR conditions will prevail across the region during the remainder
of the night ahead of an approaching winter storm. The cold front
associated with this system will sweep from north to south across
the region from 12Z/Monday through 12Z/Tuesday. Ahead of the
front winds will freshen from the southwest becoming windy at most
TAF sites around midday. Stronger winds in the mountains are
expected to generate LLWS over KMTJ, KASE, KEGE and KTEX through
the night and into the morning and strong turbulence aloft
throughout the day. As the front approaches and passes through,
TAF sites will see CIGS fall below ILS breakpoints with MVFR VSBY
developing in snow, or an initial mix of rain and snow. Brief IFR
conditions are likely. See the TAFs for detailed information on
timing and impacts to airport operations.



CO...Winter Weather Advisory from 6 AM Monday to midnight MST Tuesday
     night for COZ009-010-017.

     Winter Storm Warning from 6 AM Monday to midnight MST Tuesday
     night for COZ012-018-019.

     Winter Storm Watch from Monday evening through Tuesday afternoon
     for COZ022-023.

     Winter Weather Advisory from 2 PM Monday to 5 AM MST Tuesday for

UT...Winter Weather Advisory from noon to 9 PM MST Monday for UTZ023.

     Winter Weather Advisory from 6 AM Monday to midnight MST Tuesday
     night for UTZ028.



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