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Area forecast discussion 
National Weather Service Cheyenne Wyoming
1029 PM MST Tuesday Nov 24 2015

Short term...(this evening through Thursday night)
issued at 401 PM MST Tuesday Nov 24 2015

A quiet night across the County Warning Area tonight but a return to winter
weather on the way...beginning Wednesday. Currently some high clouds
moving across the County Warning Area as the upper flow backs slowly to southwesterly ahead
of an upper low that is dropping south along the Pacific northwest coast.
At the same time a surge of colder Canadian air is now moving
into Montana and this will continue to move south overnight...and
across the County Warning Area Wednesday morning bringing much colder air for Wednesday
through Thanksgiving day. The upper low will turn east and across
Nevada during the day Wednesday before elongating and shearing over the
western part of the country Wednesday night through Thursday night.

Expect to see snow increase over the County Warning Area Wednesday night into
Thanksgiving day as upper southwesterly flow overruns surface northeasterly
upslope flow. Initially over the plains precipitation should be pretty
light as lift will be rather weak. Some patchy freezing drizzle
possible though cold airmass may inhibit much of it. Better snow
looks to occur over parts of Carbon and Converse counties where a
general 3 to 5 inches may fall over lower elevations. Over northwest
Carbon County stronger surface winds are expected with gusts in excess
of 35 miles per hour possible so have opted to Post a Winter Storm Watch in
that area given the possibility of significant snow and blowing
snow. Elsewhere over the northwest part of the County Warning Area it appears it will be
more advisory conditions with somewhat less snow and winds. Over
the plains a general 1 to 2 inches of snow expected. Should see
snow taper off over the area during the day Thursday but still may
hang on around the mountains through Thursday night.

Long term...(friday through tuesday)
issued at 401 PM MST Tuesday Nov 24 2015

A persistent blocking pattern will keep an upper low over The
Rockies through the weekend...with the low slowly shifting into
the High Plains by early next week. Models are in better agreement
for Friday showing moist and cold upslope flow in place...which
combined with some weak upper forcing...should keep light snow in
place over much of the region through Friday night. Will be a very
light snow with minimal accumulations only kept slight
chance in the forecast for now. Models then begin a slow but
steady trek northeastward with the upper low...but details with
the individual shortwave features remain quite uncertain at this
time. Maintained slight chance to chance probability of precipitation through the weekend
due to the variability in forcing mechanisms. One thing that is
certain though is that very cold temperatures will stick around through
the weekend in this stagnant pattern. Some temperature moderation is
possible early next week if ridging develops over The Rockies as the
European model (ecmwf) indicates.


Aviation...(for the 06z tafs through 06z Wednesday night)
issued at 1024 PM MST Tuesday Nov 24 2015

Wyoming tafs...VFR prevails overnight with an Arctic cold frontal
passage Wednesday morning with ceilings lowering in the afternoon
to MVFR and then to IFR in snow during the late afternoon and
early evening.

Nebraska tafs...ceilings and visibilities lowering late tonight
and Wednesday in the wake of an Arctic cold frontal passage
with IFR developing during the day from north to south and snow
and fog developing early Wednesday evening.


Fire weather...
issued at 401 PM MST Tuesday Nov 24 2015

Cold front will pass south across the area Wednesday morning with much
colder air in its wake...which will hold for the rest of the week.
Some snow expected over many areas mainly Wednesday night and Thursday.
Concerns will remain on the low side for fire weather as a


Cys watches/warnings/advisories...
Wyoming...Winter Weather Advisory from 9 PM Wednesday to noon MST Thursday
for wyz101-103-105-110.

Winter Storm Watch from Wednesday evening through Thursday
morning for wyz104-109.



long term...rjm

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