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Area forecast discussion 
National Weather Service Cheyenne Wyoming
1002 PM MST Monday Nov 30 2015

issued at 822 PM MST Monday Nov 30 2015

Main concerns tonight are the winds in the windy corridors of
southeast Wyoming...and the potential for light snow over the
nebraksa Panhandle.

Concerning the continues to look like a marginal high
wind event with sustained southwesterly winds 30 to 40 miles per hour with
gusts between 50 and 60 miles per hour. The strongest winds should be through
the southern Laramie range and foothills as that is where the core
of strongest winds will be located tonight. Could even see some
gusts to around 65 miles per hour through this area by late tonight and early

Snow across South Dakota continues to slide southwestward toward
the Nebraska Panhandle. Becoming less excited about the potential
for accumulations outside of the Pine Ridge tonight and even
there snow may struggle to accumulate much snow. This is largely
based on the fact that westerly low level flow continues to
advect dry air into the Panhandle. So despite the middle levels
becoming saturated...precipitation will continue to fall into dry
air with a lot of precipitation evaporating before reaching the
ground. At any rate...any snow accumulations in the Panhandle
will be minimal at best tonight with little impact to travel. Snow
chances will rapidly decrease toward sunrise Tuesday morning.


Short term...(this evening through Wednesday evening)
issued at 300 PM MST Monday Nov 30 2015

Forecast concerns in the short term deal with winds as departing
low to east and incoming high from west create a strong pressure
gradient over the area.

Currently...surface low over eastern Nebraska this afternoon with
wrap around moisture making its way to the northwest of the low
into the northern Panhandle and parts of east central Wyoming. To
our west...a 1032mb surface high resides over southern Idaho and
northern Utah. 20z Craig to Casper pressure gradient stands at
roughly 4mbs. Winds at Arlington are quite gusty this afternoon.
Getting reports of 45mph out there and over the south Laramie
range. 18z 700mb winds off the GFS stands at 30kts out by
Arlington and 40kts over the southern Laramie range.

By 06z tonight...GFS 700mb winds increase to 45kts at Arlington
and 60kts over the south Laramie range. 06z Craig to Casper
850mb/700mb height gradients increase to 51mtrs/47mtrs
respectively from 27mtrs/35mtrs at 18z today. Going to be real
close at Arlington...with reports of 40-45mph out there now...and
a forecast increase in winds this evening...felt there was a good
chance at Arlington hitting high winds for at least a brief time
tonight. Added zone 110 into the High Wind Warning and moved up
the start time to 05z.

700mb winds peak out at 12z Tuesday with 50kts at Arlington and
65kts over the south Laramie range. We then start to see the winds
becoming more northwesterly and slowly decrease by 18z. We may be
able to drop Bordeaux out of the warning after 12z...but decided
to keep them going through noon at this time in case the winds do
not shift northwesterly as early as the GFS forecasts.

One last topic for tonight...models in good agreement with the
northern Panhandle getting a pretty good snow up that way. Did
increase probability of precipitation up that way into northern Sioux and eastern Niobrara
County. Forecast snow accumulations remain below advisory criteria
at 1 to 1.5 inches...but the evening shift will probably want to
monitor closely for possible upgrades.

Look for warmer temperatures as GFS 700mb temperatures climb from
-12 to -14c -8c Tuesday and -1c Wednesday. Should see
highs back above freezing Tuesday and Wednesday afternoon with
highs Wednesday possibly in the middle 40s east of the Laramie range.

Long term...(thursday through monday)
issued at 300 PM MST Monday Nov 30 2015

Upper-level ridging will dominate the central Continental U.S. Early in the
forecast period. Large scale subsidence and warming temperatures
aloft should yield pleasant weather conditions at the conclusion
of the work week for much of the County Warning Area. Low-level gradients should
not be particularly strong do not expect winds to be
all that strong outside of the typically windy areas. The GFS is
the most optimistic with 700 mb temperatures climbing above +4 degree c along/east
of the Laramie range by Friday afternoon...while the European model (ecmwf)/Gem are a
bit cooler around +2 degree c. Either way...widespread highs of 50+
will be a good bet with weak downslope in place across the High
Plains. The medium range models are in good agreement with a fast
moving shortwave trough affecting the area by Friday night/Sat. This
system appears much too dry to yield any precipitation...but it should
result in cooler and windier weather for Saturday. Dry weather
conditions will prevail through the remainder of the period.


Aviation...(for the 06z tafs through 06z Tuesday night)
issued at 957 PM MST Monday Nov 30 2015

Mainly VFR across the forecast area tonight. The exceptions will
be in the snowy and Sierra Madre ranges and adjacent area where
some light snow and lower stratus will produce IFR to MVFR. The
same GOES for northern portions of the western Nebraska Panhandle
where some light snow will fall tonight. Again IFR to MVFR for
this area tonight. Conditions will improve across the area into
Tuesday morning with VFR developing everywhere.

Winds will be strong across much of southeast Wyoming...especially
the wind prone areas where gusts of 45 to 60 miles per hour will be common
tonight through Tuesday morning. Gusty winds will also occur into
the western Nebraska Panhandle with gusts to 45 miles per hour likely by
Tuesday afternoon.


Fire weather...
issued at 300 PM MST Monday Nov 30 2015

Strong winds this afternoon and especially tonight as high
pressure builds into the area from the west. Fortunately...there
is adequate snow cover and cold temperatures are widespread to
preclude and fire weather impacts. May need to reconsider towards
middle week as warmer temperatures occur over southeast Wyoming that
will end low level snow cover. Still...afternoon humidities
Wednesday into Friday are still in the middle to upper 20 percent fire weather concerns should be minimal.


Cys watches/warnings/advisories...
Wyoming...High Wind Warning until noon MST Tuesday for wyz106-110-116-117.




short term...gcc
long term...clh
fire weather...gcc

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