Area Forecast Discussion
Issued by NWS Cheyenne, WY

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915
FXUS65 KCYS 220411
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
911 PM MST Tue Nov 21 2017

.UPDATE...
Issued at 906 PM MST Tue Nov 21 2017

Latest water vapor loop was showing some mountain waves taking
place near Arlington. This is causing wind speeds to increase in
that region to speeds of 40 to 45 mph with some gusts up to 55
mph during the last hour.  As a result, we are going ahead and
start the High Wind Warning around 06z even though the rest of the
forecast zones may end up starting a little later. The rest of
forecast looks to be in good shape.
&&

.SHORT TERM...(This evening through Wednesday night)
Issued at 235 PM MST Tue Nov 21 2017

Relatively minor wind event still shaping up for later tonight
into Weds across mainly the south Laramie Range and in the wind-
prone Bordeaux area. Looks like it will occur a little later than
earlier thought with 7H winds not coming up until closer to 12Z.
Some concern for the Bordeaux area as the stronger winds will be
south of that area and the direction not so favorable. Will
upgrade the current watch to a warning but again delay the start
time. Otherwise mainly dry overnight through Weds night other than
a few possible snow showers over the higher mtns into Weds
morning. Surface front will erode back east overnight so areas
close to the Laramie Range may see rising temperatures later
tonight as downslope flow develops. Warmer over the plains Weds as
the warmer downslope winds spread east across the Panhandle.

.LONG TERM...(Thanksgiving Day through Tuesday)
Issued at 235 PM MST Tue Nov 21 2017

Mild and mainly dry weather seen for the CWA as upper ridging will
be the prevalent feature influencing the weather. Looks like
another strong wind event for the wind-prone areas Thursday night
into Friday as a decent shortwave moves across the northern
Rockys into the northern plains and sharpens the surface pressure
gradient over the area. Modest cool front passes by Friday but
temps still remaining above seasonal averages through Monday. next
significant cold front looks to arrive early Tuesday.

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 423 PM MST Tue Nov 21 2017

VFR conditions will be the rule tonight into Wednesday. However,
more jet energy is expected to move over the upper level ridge
tonight into Wednesday morning. This will cause the surface
pressure gradients to tighten up a bit especially over the wind
prone areas. As a result, it will be a bit more windy beginning
late Wednesday morning into Wednesday afternoon due to good mixing
and stronger wind speeds aloft.


&&

.FIRE WEATHER...
Issued at 235 PM MST Tue Nov 21 2017

Sufficiently high min humidities and less wind will keep fire
weather concerns low for the rest of the week. There will be a
couple windy periods mainly around the mountains but fuels in
those areas non-critical.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...High Wind Warning from 4 AM to noon MST Wednesday for WYZ106-116-
     117.

NE...None.
&&

$$

UPDATE...REC
SHORT TERM...RE
LONG TERM...RE
AVIATION...REC
FIRE WEATHER...RE



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