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920
FXUS65 KCYS 070046
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
546 PM MST Fri Dec 6 2019

.UPDATE...
Issued at 544 PM MST Fri Dec 6 2019

A High Wind Warning is in effect for the wind prone areas of
southeast Wyoming beginning 5 AM MST Saturday and ending 2 AM MST
Sunday. Winds could gust as high as 65 MPH. Please see the High
Wind Warning text for more information.

&&

.SHORT TERM...(This evening through Saturday)
Issued at 135 PM MST Fri Dec 6 2019

Clearing skies and warmer temperatures were the story for this
afternoon as a ridge of high pressure has strengthened over the
mountains. Little change is expected over the next 12 hours as the
main ridge axis moves overhead by early Saturday. At the surface,
high pressure will be located over central to western Wyoming. This
will mean above average and mild temperatures with little cloud
cover through much of the day. Surface pressure gradients will
also begin to increase heading through Saturday moring.
Concurrently, a jet streak aloft from an approaching low amplitude
west coast trough is expected to reach eastern Wyoming by 18z
Saturday. This will set the stage for some high wind potential
through Saturday and Sunday. Models have backed off on the more
aggressive solutions and have focused more on the Arlington area
for high wind potential. Given the degree of wind aloft (650 mb
jet near 50 kts) it is possible bordeaux and the summit will get
some stronger gusts but it is more uncertain at this time. Due to
the uncertainty, the High Wind Watch was not upgraded this cycle.
Will allow the night crew to make the decision with more up to
date data.

.LONG TERM...(Saturday night through Friday)
Issued at 135 PM MST Fri Dec 6 2019

Gusty winds may continue through Saturday night as a weak upper
level trough passes overhead. Clouds will increase Saturday night
and Sunday morning as a northern branch clipper trough moves in
from southern Canada. This will drive a cold front south through
the area bringing cooler temperatures and the chance for snow.
Widespread coverage is not expected with mainly the northern
slopes of the higher terrain experiencing the best snow. Highs
will drop a few degrees to near normal through Sunday and the
first part of next week. Northwesterly flow will develop across
the eastern 3rd of the US by Tuesday, driving much colder arctic
air southward across the center of the country. Wyoming and
western Nebraska should miss out on the coldest air but temps
will likely remain near or just below average.

Not much in the way of active weather is forecast from Tuesday
through Friday with less active zonal flow across the area. A few
bursts of light precipitation and gusty winds are possible with
any small systems. However, the pattern looks more favorable for
above average temperatures and normal to below normal precip through
the 2nd week of December.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 453 PM MST Fri Dec 6 2019

VFR conditions across all terminals with west winds 10 kts or less
across all sites under generally clear skies, except KRWL which
will gust up to 25 kts through 07/01Z. West winds increase between
07/11-14Z across southeast Wyoming, and after 07/17Z across the
Panhandle. While the gap regions could see stronger gusts,
terminals will see gusts up to about 35 kts at the Wyoming sites.
Winds at 10K feet will be around 60 kts out of the W and Nw.
expect turbulence near mountain terrain.


&&

.FIRE WEATHER...
Issued at 135 PM MST Fri Dec 6 2019

No fire weather concerns through this weekend and into next week
with recent widespread heavy snow and minimum daytime humidity
values above 30-40 percent. Windy conditions are expected across
most of southeast Wyoming this weekend with locally strong winds
possible.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...High Wind Warning from 5 AM Saturday to 2 AM MST Sunday for
     WYZ106-110-116-117.

NE...None.
&&

$$

UPDATE...CW
SHORT TERM...AL
LONG TERM...AL
AVIATION...AB
FIRE WEATHER...TJT