Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 200634

Area Forecast Discussion
National Weather Service Cheyenne WY
1134 PM MST Mon Feb 19 2018

Issued at 1039 PM MST Mon Feb 19 2018

Updated to bring down Winter Weather Advisories and Winter Storm
Warnings a bit early for our Wyoming zones, but added a Wind Chill
Advisory for frostbite potential from wind chills of 15 to 30
below zero across the southern Wyoming zones through early
morning. Based on snowfall rates rapidly falling off across the
Nebraska Panhandle, we may be able to drop some of the Warnings
and Advisories there as well around midnight.

UPDATE Issued at 848 PM MST Mon Feb 19 2018

Made a few updates to the Winter Storm Warning across the northern
Nebraska Panhandle to carry it through the early morning hours
since snowfall will likely linger up there for a few more hours
before tapering off before daybreak. Also, extended the Winter
Weather Advisory in the south to the east to include the Kimball
and Sidney areas since a very slow moving band of heavy snow will
make slow progress eastward across those areas through early
morning. With the very cold temperatures, it won`t take the roads
long to get pretty slick. Otherwise, expect to allow the Winter
Storm Warning to expire by midnight where we have it up in
Wyoming, with eastern Laramie county continuing until 6 AM with
the Winter Weather Advisory, but we may be able to drop that a
little earlier if the trend of snow diminishing to the west
continues. Updated forecast package has been sent.


.SHORT TERM...(This evening through Tuesday night)
Issued at 235 PM MST Mon Feb 19 2018

Current forecast looking pretty much on track with some bands of
heavier snow now over western parts of the CWA working northeast.
Should see a period of heavier snow spread east across much of the
rest of the CWA this evening bringing a general 2-4 inches of
additional snowfall. Snow should taper off later tonight as
better energy and forcing shifts east of the area. Will keep
current hilites in place and defer to evening shift for any
changes. Very cold across the CWA tonight with mins in the single
digits below zero over much of the area. Winds light but still
cold produce some wind chills around -20 in some areas.

Mainly dry across the CWA Tuesday and Tuesday night outside of
some mtn snow showers. Main story will be cold temperatures
holding across the area as an arctic high settles down the high
plains. Max temps Tuesday only in the teens across much of the
CWA. Fortunately winds will remain rather light. Very cold again
Tuesday night with below zero temps once again.

.LONG TERM...(Wednesday through Monday)
Issued at 235 PM MST Mon Feb 19 2018

Some moderation of temperatures expected Weds and Thursday but
still chilly as the upper flow turns southwesterly and the cold
arctic high slips east away from the CWA. Snow showers will
continue to occur at times over the higher mtns in favorable swly
flow, aided by weak disturbances ejecting northeast ahead of an
upper trough over the western CONUS. GFS cuts off an upper low
over northern AZ Friday then moves it eastward to the southern
plains by late Saturday. EC maintains an open trough, moving it
across the area Friday night. In either case any pcpn should stay
confined to the mtns for the most part though some snow showers
possible over the plains Friday night if the EC pans out.
Otherwise a minor push of cooler air drops down the plains
Thursday night then warmer conditions should spread back over the
area over the weekend. Weak system Monday may bring some minor
cooling again.


.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1131 PM MST Mon Feb 19 2018

Wyoming TAFS...MVFR at Rawlins until 11Z, then VFR. Occasional IFR
at Laramie and Cheyenne until 10Z, then VFR.

Nebraska TAFS...Occasional IFR at Chadron and Alliance until 12Z,
then VFR. MVFR at Scottsbluff until 09Z, then VFR. IFR at Sidney
until 10Z, then VFR.


Issued at 235 PM MST Mon Feb 19 2018

No fire weather concerns anticipated through late this week with
cool to cold conditions and snow cover over many areas resulting
in non-critical conditions.


WY...Wind Chill Advisory until 6 AM MST Tuesday for WYZ106-109>119.

NE...Winter Storm Warning until 5 AM MST Tuesday for NEZ002-003-095-

     Winter Weather Advisory until 6 AM MST Tuesday for NEZ019>021-



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