Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 230011

Area Forecast Discussion
National Weather Service Grand Junction CO
511 PM MST Wed Feb 22 2017

.SHORT TERM...(Tonight through Thursday night)
Issued at 348 PM MST Wed Feb 22 2017

Very mild and windy conditions were prevalent across the forecast
area this afternoon under strong southwesterly flow. While our
latest storm has been a bit slow to start today, stratiform
showers of rain and snow have developed north of I-70. Impacts
have been minimal thus far with latest webcams showing generally
wet roads. Showers are anticipated to increase in coverage tonight
and into tomorrow morning as a cold front works through the
region. While models originally had the front getting hung up on
the central mountains it now appears that the front will work its
way through the southern mountains as well by the time this storm
exits the area on Friday. The heaviest accumulations are expected
to occur tonight into tomorrow morning in tune with the
progression of the cold front. Current winter weather highlights
remain on track and did not see the need to add any additional
zones as amounts will remain below criteria. Many valley locations
will also see minimal snow accumulation, or at least a wintry mix, after
the colder air works in. As always, please check the latest
forecast and road conditions before travelling!

High temperatures tomorrow will be some 15 to 20 degrees cooler
than today and overnight lows will drop below freezing across the
board for Thursday night. The closed low will transition to an
open wave on Thursday as it heads towards the northern Plains with
an unsettled northwesterly flow remaining in its wake. This will
result in a continuation of showers over the higher terrain as
activity begins to shut down from west to east.

.LONG TERM...(Friday through Wednesday)
Issued at 348 PM MST Wed Feb 22 2017

An embedded wave in the northwesterly flow will allow clouds and
showers to linger on Friday and continuing through early Saturday.
Precipitable water values associated with this disturbance range from
0.15 to 0.20 inches which is slightly below normal, so not too
impressive at the moment. Upper level support is also not there as
the jet remains well south of the area. Therefore, generally
orographic showers look to be the main concern on Friday with the
northern and central mountains favored. Tightening westerly flow
aloft will result in dry conditions and a breezy afternoon on
Saturday as the tail of a +110kt jet moves in.

A progressive pattern will begin on Sunday and looks to continue
through at least Tuesday. This will consist of a weak shortwave
trekking across the forecast area on Sunday with southwesterly flow
increasing on Monday ahead of our next significant storm. While
extended models differ on the intensity and arrival of the
approaching Pacific trough general consensus has the system digging
into the Great Basin and impacting the region as early as Monday
night. As the previous forecaster mentioned this suggests a
return to unsettled conditions and the potential for moderate to
heavy precipitation. Something else to note; 700mb temperatures
associated with this storm range from -10 to -14 deg C so if this
pans out it could bring us a nice cold spell!


.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 511 PM MST Wed Feb 22 2017

A cold front associated with the latest winter storm was aligned
along a KPUC-KCAG-KSBS line at 00Z/Thursday. This feature will
largely be driving the weather at TAF sites across the area
through the next 24 hours. The front is expected to sweep
southeastward across the area during the night, exiting to the
south of the Colorado border by 12Z/Thursday. Ahead of the front
expect gusty west to southwest winds at 15 to 25 mph with gusts to
35 mph. In the higher elevations winds will be quite strong with
the jet stream moving overhead resulting in wind shear at a number
of sites. Best chances for precipitation will come with frontal
passage which is likely to bring MVFR CIGS/VSBY with periods of
IFR conditions and a prolonged period where CIGS will be below ILS
breakpoints. Conditions improve at all sites after 18Z/Thursday.
Detailed information regarding timing and impacts can be found in
the TAFs.



CO...Winter Weather Advisory until 9 AM MST Friday for COZ004.

     Winter Weather Advisory until 9 AM MST Friday for COZ003-013.

UT...Winter Weather Advisory until 6 PM MST Thursday for UTZ023.



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