Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 201318
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
618 AM MST Tue Feb 20 2018

.UPDATE...
Issued at 616 AM MST Tue Feb 20 2018


Looking at radar this morning and area observatioons across the
southern Panhandle, looks like we can let the Winter Weather
Advisory expire.  Did let it go at 6 AM. Updates sent.

&&

.SHORT TERM...(Today through Thursday)
Issued at 345 AM MST Tue Feb 20 2018

Latest Radar and IR satellite trends showing the snow beginning to
ease over the Nebraska Panhandle this morning as the upper level
system moves off to the northeast. Radar showing a few bands of
snow over the southern Nebraska Panhandle in the Advisory area, so
will keep the advisory going through 6AM today. Across the
northern Panhandle, we are seeing northwest winds being reported
on area METARs, so do think the snow is done up there. Went ahead
and cancelled the Winter Storm Warnings for the northern
Panhandle earlier.

Across southeast Wyoming this morning, have been seeing bitter
cold windchills being reported across a widespread area. WYDOT
observations over the Summit over to Arlington have been reporting
colder than 30 below windchills for the past several hours and do
expect this to continue. So issued a WindChill Warning for the
I-80 Corridor from west of Cheyenne through Arlington for the rest
of the overnight hours.

Temperatures are going to be a challenge today with the widespread
snow pack in place. Did undercut guidance on highs to day and
overnight lows tonight, but may not have gone enough. Would think
the dayshift will be doing a few temperature updates through the
day to match up with current observation trends.

Will be dealing with windchill headlines again tonight for some
areas. Especially the northern Panhandle and Converse/Niobrara
Counties that have a very heavy snowpack. Skies are going to be
clear tonight with south to southwest winds 6-10 mph. Will let the
dayshift tackle that issue with the afternoon issuance.

Another shortwave for Wednesday evening into Thursday approaching
from the northwest. Going to see some snow activity in the western
mountains and possibly across the southern Panhandle during this
time. For now, kept the snow out of the Panhandle as we have
downsloping winds that would not be too conducive for snow out
that way.

.LONG TERM...(Thursday night through Monday)
Issued at 345 AM MST Tue Feb 20 2018

Thursday night/Friday...As a shortwave trough aloft moves overhead
on southwest flow aloft, will see a slight chance of light snow near
the Colorado state line Thursday night. Orographic type snow will
continue in the afternoon from the Sierra Madres eastward through
the southern Laramie Range.

Saturday...A shortwave trough aloft moves overhead early in the day
producing a chance of snow, then drying in the afternoon in the wake
of the trough. Windy in the afternoon per progged low and mid level
gradients.

Sunday...Windy again per progged low and mid level gradients. A fast
moving shortwave trough aloft is forecast to affect our counties in
the afternoon, producing a chance of snow over our Snowy and Sierra
Madre Ranges.

Monday...West northwest flow aloft continues with minimal chances
for precipitation due to relatively dry low and mid levels. Maximum
temperatures in the 30s to mid 40s at lower elevations with 700 mb
temperatures near -14 Celsius.

&&

.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 434 AM MST Tue Feb 20 2018

Wyoming TAFS...VFR, with occasional MVFR at Laramie through 15Z.

Nebraska TAFS...VFR, with occasional MVFR at Alliance and Sidney
through 16Z.


&&

.FIRE WEATHER...
Issued at 345 AM MST Tue Feb 20 2018

Snow will end by sunrise today across all of southeast Wyoming and
Nebraska Panhandle. Very cold temperatures over the next couple
days. Widespread snowpack in place, so fire weather concerns are
going to be minimal through much of the week.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Wind Chill Advisory until 8 AM MST this morning for WYZ101-102-
     106>109-111>114-118-119.

     Wind Chill Warning until 8 AM MST this morning for WYZ110-
     115>117.

NE...None.
&&

$$

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


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