Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 152300

Area Forecast Discussion
National Weather Service Cheyenne WY
400 PM MST Wed Nov 15 2017

.SHORT TERM...(This evening through Thursday)
Issued at 248 PM MST Wed Nov 15 2017

Dry and mild conditions expected to prevail over the CWA this
period. Attention will be focused on some strong winds which look
likely around the Arlington area later tonight through Thursday...
expanding into possible western Converse county by Thursday
afternoon as lee troughing develops along the Laramie Range in
response to a shortwave ejecting ENE across the northern Rockys
into Canada. Pattern not favorable for the Bordeaux area due to
the expected nearness of the sfc trough. Stronger mid-level winds
also farther north with high wind threat looking lower for
northern Carbon county so opted to drop that area from the high
wind watch, but still some gusty winds expected during the day in
that area.

.LONG TERM...(Thursday night through Wednesday)
Issued at 248 PM MST Wed Nov 15 2017

Main focus this period will be late Thursday night through most of
Friday with a pretty good snowfall event expected over the higher
mtns. An upper trough will move into the Pacific northwest
Thursday evening and sweep east and across the area Friday
evening. Moisture will increase ahead of this system and ride up
the west-facing slopes of the Sierra Madre/Snowy Ranges later
Thursday night and continue on Friday producing some good snows.
Should see in the neighborhood of a foot of snow there before the
upper trough swings across early Friday evening bringing snow to
an end. Will keep the Winter Storm Watch going but trimmed it a
bit due to the expected ending of snow early Friday evening.

Other concern will be for a potential Bora event for a time late
Friday afternoon and evening as a cold front sweep across the CWA.
NAM depicting some 40-50kt winds with some downward omega
spreading into the far se Wy plains so will have to watch.

Saturday looking breezy and cool. Milder and dry weather returns
Sunday into early next week but may have some strong winds in
favored areas later Monday as lee troughing deepens over the high
plains.  Next cold front due about Wednesday.


.AVIATION...(For the 00Z TAFS through 00Z Thursday afternoon)
Issued at 400 PM MST Wed Nov 15 2017

Prevailing VFR with cloud CIGS 15000-25000 FT AGL. Strong southwest
surface winds and mountain wave turbulence along and west of the
Laramie Range will be the primary aviation concerns from late
tonight through Thursday afternoon. Gusts of 35-45 KT are forecast
for terminals west of the Laramie range, and 20-30 KT to the east.


Issued at 248 PM MST Wed Nov 15 2017

Fire weather concerns expected to be low for the rest of the week
through the weekend as a trend towards cooler temperatures sets in
and keeps weather factors mostly non-critical. The will be some
stronger winds Thursday around the mtns then a cold front will
sweep across the area later Thursday with a period of gusty winds
behind it. Snow will fall mainly over the mtns Thursday night and


WY...Winter Storm Watch from Thursday evening through Friday
     afternoon for WYZ112-114.

     High Wind Warning from midnight tonight to 6 PM MST Thursday for

     High Wind Watch from Thursday morning through Thursday afternoon
     for WYZ101.



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