Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 130912

Area Forecast Discussion
National Weather Service GRAND JUNCTION CO
312 AM MDT Fri Oct 13 2017

.SHORT TERM...(Today through Saturday)
Issued at 310 AM MDT Fri Oct 13 2017

Dry weather continues for all of eastern Utah and western Colorado
through tonight as southwest winds start to increase. Surface
gradients will be tightening up as a cold front pushed slowly east
across the Great Basin with an upper level jet moving overhead.
Expect winds to pick-up over the hills this morning and mix into
the valleys this afternoon. Very dry conditions at the surface,
combined with the winds and dry vegetation will bring critical
fire weather conditions back into the forecast. Winds let up early
this evening across the valleys but will continue to gust over the
mountains with the front driving through the forecast area between
midnight tonight and Noon Saturday. Above normal temperatures
expected again today with gridded temps nudged toward warmer MAV
guidance. Front is packing decent cold air and temps on Sunday
will be down a solid 10 to 15 degrees from what we see this
afternoon in most areas. A few light showers are also expected
across our far northern zones on Saturday, but very dry low levels
will be hard to penetrate and expect more wind than significant
rain/snow from these showers.

.LONG TERM...(Saturday night through Thursday)
Issued at 310 AM MDT Fri Oct 13 2017

A much colder and very dry airmass will accompany the passage of an
upper level trough on Saturday, with precipitable water values
lowering to a little above 0.1 inches to the north and less than 0.1
inches for most areas by Saturday night. Clear skies will also lead
to excellent radiational cooling which should result in all areas
seeing below freezing temperatures and the potential for widespread
season ending freeze in the areas that have not seen it yet.
Something for later shifts to consider potential Freeze Watches or
Warnings for the Saturday night into Sunday morning timeframe.

A dry northwest flow will remain in place Sunday and Monday with
below normal temperatures and a slow warming trend. A progressive
shortwave ridge of high pressure will slide over the region Tuesday
morning, followed by the shift to southwest flow by Tuesday
afternoon. This will help temperatures warm back to above normal
levels by mid-week and beyond. A few embedded shortwaves will
move through the flow for the latter half of the work week as
more energy moves into the Pacific Northwest with a trough of low
pressure eventually reloading over the western states by the end
of the week. These shortwaves appear mostly dry at the moment
through Thursday, with some increase in mid and high clouds and
breezy southwest winds during the afternoons.


.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 310 AM MDT Fri Oct 13 2017

Breezy to windy conditions expected for the next 24 hours as a
strong upper level jet and surface cold front move into the
region. Expect areas of turbulence, especially in the lee of
mountain ranges and pockets of LLWS in the valleys. Otherwise, VFR
conditions are expected to persist with only passing mid and high
clouds, all above ILS breakpoints.


Issued at 310 AM MDT Fri Oct 13 2017

A cold front will be pushing across the Great Basin today with a
strong upper level jet moving overhead. This will bring breezy to
windy conditions to much of eastern Utah and western Colorado
today. Critical fuels reported across much of western Colorado and
weather parameters will be aligned for several hours this
afternoon. As a result, a Red Flag Warning will be issued Colorado
Fire Weather Zones 200, 202, 203, 290 and 293 for low relative
humidity, dry fuels, and gusty winds exceeding 30 mph at times.
The winds are expected to let up across the valleys by early this
evening with humidity values improving as the front approaches.
The cold front is expected to pass through between midnight
tonight and noon MDT Saturday. No significant precipitation will
occur with this frontal passage.


CO...Red Flag Warning from noon today to 6 PM MDT this evening for



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