Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 192328

Area Forecast Discussion
National Weather Service GRAND JUNCTION CO
528 PM MDT Thu Oct 19 2017

.SHORT TERM...(Tonight through Friday night)
Issued at 245 PM MDT Thu Oct 19 2017

A quick moving shortwave trough has allowed mid and high level
clouds to increase across much of the region today with a few
light showers developing down south. Available moisture remains
low so no significant precipitation is expected and gusty outflow
winds will be the primary threat with showers. Increased cloud
cover will limit radiational cooling this evening so overnight
lows will be several degrees warmer than previous nights.

Friday will see the continued tightening of the southwesterly wind
gradient as the upper level Pacific trough and associated cold
front dig into the Great Basin. The main forecast challenge for
the short term period will be whether or not to issue any wind
advisories in response to the gusty prefrontal winds. While
criteria will be close to being met in northwest Colorado Friday
afternoon opted not to issue any highlights this shift since
increased cloud cover may prevent those stronger winds from mixing
down to the surface. Would definitely encourage later shifts to
take a closer look at this situation once new guidance comes in
this evening. Generally, wind gusts of 25 to 40 mph can be
expected across the region through the afternoon and early
evening hours on Friday.

The cold front will begin to move through northeastern Utah Friday
evening with scattered to numerous showers developing along and
ahead of the boundary, though the higher terrain will be favored
for activity. Snow levels will be high at the onset of the storm,
at or around 10kft, before plummeting to potentially less than
7kft as the significantly colder air mass infiltrates the region.
This event will be short lived as the cold front will have
progressed out of our forecast area by daybreak Saturday. Storm
total snowfall is still below advisory criteria with amounts of 1
to 3 inches expected for the Colorado mountains with some locally
higher amounts possible above 10kft. Still, please use caution if
travelling over any of the mountain passes Friday night as the
roads may become slick and snowpacked and visibility may briefly
be reduced in periods of blowing snow.

.LONG TERM...(Saturday through Thursday)
Issued at 245 PM MDT Thu Oct 19 2017

A few snow showers will linger along the Continental Divide early
Saturday before this storm becomes a mere memory as the trough
lifts northeast into the Plains. Dry northwesterly flow will set
up in its wake for a mostly sunny but chilly Saturday afternoon.
This drying trend will continue Sunday and beyond as a ridge of
high pressure amplifies over the southwestern CONUS. Temperatures
will rebound in response and be back to near or slightly above
seasonal norms by early next week. An upper level trough looks to
elongate and dive down from north-central Canada mid to late next
week which could see the return of cooler and potentially wetter
conditions across our area, but confidence is low at this time.


.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 528 PM MDT Thu Oct 19 2017

Mid and high level clouds will be thinning out across the region
through the evening as this weak system moves through.
Precipitation has been sparse and is mostly virga leading more to
gusty winds than rainfall. Valley locations should see winds
subside after sunset. In the higher elevations winds should begin
to increase overnight as the gradient tightens ahead of the next
system. This could lead to some mountain wave turbulence through
the next 24 hours. As heating commences late tomorrow morning
winds aloft should mix to the valleys. Gusts of 25 to 35 mph will
be widespread across the region and could cause some flight
operations issues.




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