Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 300532

Area Forecast Discussion
National Weather Service Grand Junction CO
1132 PM MDT Wed Mar 29 2017

.SHORT TERM...(Tonight through Friday night)
Issued at 310 MDT Wed Mar 29 2017

Flat ridge shifts east tonight with dry and cool conditions
holding in place. Pattern starts to buckle once again on Thursday
as another digging upper level low pushes southeast across the
Great Basin with a target zone near the Four Corners Thursday
night/early Friday morning. Flow aloft will be shifting to the
southwest and south as the low approaches with moisture swinging
around the base and lifting northward in improving difluent flow
on eastern side of the low. This will kick off a few showers over
eastern Utah by Thursday afternoon with showers increasing in
coverage Thursday night and Friday as the low moves into the area.

Heavy snow is expected to fall over the eastern Uinta Mountains
above 8000 feet with low level flow becoming northeasterly as the
low moves into the Four Corners. Have issued a winter storm watch
for this area where snowfall amounts may approach 20 inches by
early Saturday morning. The Bookcliffs, La Sals and Abajo
mountains in eastern Utah will also see snow developing Thursday
night with accumulations expected to be under warning criteria.

Across western Colorado, the big winners are likely to be the San
Juans, Grand Mesa and the West Elks with upwards of a foot
possible, but still under warning criteria. Will throw out that we
ran with a 12 to 13 to 1 ratio in the San Juans and if this
comes in a few degrees colder, we will see those amounts jump, so
keep checking the latest forecast as we get dialed in. Even with
the low ratios, peaks above 10-11k could see close to 18 inches,
but confidence of widespread foot plus snowfall just not high
enough this afternoon.

With the strengthening southerly flow in place on Thursday,
expected a warmer day with temperatures running up to 10 degrees
above normal. Then we see a front sweep through Thursday night,
resulting in nosediving temperatures and dropping snow levels to
as low as 6500 feet by Friday morning. No significant
accumulations expected at these lower levels at this time. Best
shot of valley snowfall accumulating will be across northwest
Colorado and over the southern Valleys from basically Mesa Verde
National Park east to Durango and Pagosa Springs. Could see a
sloppy 1 to 3 inches with a few of the higher surrounding
communities seeing a bit more.

.LONG TERM...(Saturday through Wednesday)
Issued at 310 PM MDT Wed Mar 29 2017

The heads east Saturday with a few showers lingering over our
forecast area through Saturday afternoon with another flat ridge
building in behind the exiting system. This brings increasing
westerly flow and drier conditions in for Sunday before another
fast moving wave brings more rain and snow to the area on Monday.
This system is tracking further north and shows some signs of
closing off over northern Wyoming Monday afternoon. This will
shift focus for heavier precipitation into our northern and
central mountains. This system exits on Tuesday with dry weather
then expected through midweek. Temperatures will be running near
normal through this period.


.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1132 PM MDT Wed Mar 29 2017

High then mid level cloudiness will spread into the region ahead
of the next storm taking shape in the Great Basin today. Really
minimal impacts to aviation expected through the bulk of this
forecast with small probabilities of ILS break points being met
late. VFR will dominate the forecast with deteriorating conditions
Thursday night persisting into Friday.


UT...Winter Storm Watch from Thursday evening through Saturday
     morning for UTZ023.



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