Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 272125
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
225 PM MST Mon Feb 27 2017

.SHORT TERM...(This evening through Wednesday night)
Issued at 124 PM MST Mon Feb 27 2017

Front has moved into Carbon County this afternoon as advertised by
guidance. Metars out by Rawlins showed a period of 1/4SM
visibilities and Webcams are showing poor visibilities between
Rawlins and Arlington early this afternoon. SNOTELs are starting
to show accumulating snow in both the Sierra Madre and Snowy
Ranges. Will let the current headlines stand as they are as they
look to be in pretty good shape.

Heaviest snow continues to be forecast on guidance from now
through maybe 06Z tonight as the front slowly moves south into
northwest Colorado. Attention turns to Tuesday winds.

GFS 700mb winds on the increase Tuesday. By 21Z 700mb winds up to
45kts across Carbon County. GFS high wind guidance showing Craig
to Casper 850/700mb height gradients exceeding 50mtrs by 21Z,
peaking out at 66/65mtrs respectively by 06Z Wednesday. Decided to
go with a High Wind Watch for the wind prone areas (Bordeaux and
south Laramie Range). Arlington is going to be added once the
current WSW expires early Tuesday. Should easily see 65+ MPH winds
in the wind prone areas. Some concerns for areas outside the wind
prone areas. MAV guidance for Cheyenne showing 27kts sustained
Wednesday, so later shifts will need to consider expanding the
wind headlines. Strong winds to continue through the day
Wednesday.

.LONG TERM...(Thursday through Monday)
Issued at 300 PM MST Mon Feb 27 2017

Thursday...Continued windy with a slow warming trend as heights and
thicknesses rise slowly. With brisk northwest flow aloft and progged
low and mid level gradients, this day looks quite windy, with our
wind prone locations perhaps nearing or exceeding high wind
criteria. Minimal low and mid level moisture suggests a dry day.

Friday...Warming trend really gets going as the flow aloft backs to
westerly and more zonal, inducing a strengthening surface lee trough
and more downslope west winds.

Saturday...Warming trend continues with west to east, zonal flow
aloft, helping temperatures to rise considerably from Friday.
Continued dry with limited low and mid level moisture.

Sunday...As the flow aloft backs even more to southwest, we may see
enough influx of mid level moisture for an increase in rain and snow
shower coverage due to orographics over our Snowy and Sierra Madre
Ranges. Perhaps some slight cooling due to more cloud cover.

Monday...Fast moving and low amplitude shortwave trough aloft moves
across Wyoming, then into North Dakota by late Friday, sending a
primarily dry cold front across our counties due to relatively dry
low and mid levels.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1026 AM MST Mon Feb 27 2017

Wyoming TAFS...VFR prevails, except at Rawlins where MVFR exists
from 20Z to 01Z. Winds gusting 24 to 38 knots through 01Z, then
winds decreasing. Winds gusting to 30 knots after 15Z Tuesday.

Nebraska TAFS...VFR prevails, except for MVFR at Chadron and
Alliance from 00Z to 15Z, and MVFR at Scottsbluff from 02Z to 15Z,
and at Sidney where IFR occurs from 06Z to 15Z.

&&

.FIRE WEATHER...
Issued at 300 PM MST Mon Feb 27 2017

Winds will be on the increase through the upcoming week as several
systems move through the area almost on a daily basis.
Fortunately with an existing snow pack and cold temperatures,
fire weather concerns will be minimal.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Winter Weather Advisory until 5 AM MST Tuesday for WYZ109-111-
     113-114.

     Winter Storm Warning until 5 AM MST Tuesday for WYZ110-112.

     High Wind Watch from Tuesday afternoon through Wednesday evening
     for WYZ106-116-117.

NE...None.
&&

$$

SHORT TERM...GCC
LONG TERM...RUBIN
AVIATION...RUBIN
FIRE WEATHER...GCC



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