Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 241018

Area Forecast Discussion
National Weather Service Cheyenne WY
318 AM MST Fri Feb 24 2017

.SHORT TERM...(Today through Sunday)
Issued at 300 AM MST Fri Feb 24 2017

Periods of light snow will continue across much of southeast WY and
the western NE Panhandle today with wrap-around moisture associated
with the departing low. Outside of the mountains, up to one inch of
new accumulation can be expected with around 3 to 6 inches over the
Snowy and Sierra Madres. This storm is all but over, but we decided
to keep the Winter Storm Warning going through 18z due to extremely
icy roads resulting from wet/slushy snow that froze last evening or
overnight. The day shift can re-evaluate during or after the Friday
morning commute.

The next mid-level shortwave swings across the Intermountain West &
across the CWA on Saturday. The resulting pressure falls during the
early morning hours should support an H85 CAG-CPR gradient of 40 to
50 meters between 06z and 15z. This combined with 30-40 kts of flow
at H7-H8 will yield windy conditions at Arlington and even Bordeaux
as a weak lee trough moves onto the plains. At this time, this does
not appear likely to necessitate a High Wind Warning but we may see
a few gusts of 50 to 55 MPH early Saturday morning. Wind speeds may
increase across the high plains on Saturday afternoon as the trough
pushes eastward. Regarding temperatures, remaining cold through the
weekend w/ deep snow pack and large scale troughing. Sunday will be
dry with a shortwave ridge in between systems, trending warmer with
more sunshine than previous days but still likely below freezing.

.LONG TERM...(Sunday night through Thursday)
Issued at 315 AM MST Fri Feb 24 2017

00Z/06Z medium range model consensus progs weak upper ridging over
the CWA Sunday night. Flow aloft backs to southwest Monday as the
next Pacific trough tracks eastward through the Intermountain West
and deepens over the Rocky mountains and high plains Monday night
and Tuesday. Expect westerly winds to increase as well with gusts
to 35 kt across much of the CWA. West-northwest winds could be
stronger Wednesday with gusts to 40 kt following the passage of a
Pacific cold front. Embedded shortwave energy will provide
sufficient QG lift in tandem with Pacific moisture for decent snow
coverage along and west of the Laramie Range. Advisory criteria
snowfall amounts will be possible over the Snowy/Sierra Madres.
Areas east of the Laramie Range will remain dry due to downslope
flow. Snow coverage decreases Tuesday night and Wednesday, limited
to weak orographics over the mountains as northwest flow aloft
prevails. The air mass dries out Wednesday night and Thursday,
with breezy westerly winds. Below normal temperatures will prevail
through much of next week, especially with the extensive snow
pack. Highs will average in the 20s and 30s, except for teens
mountains. Lows will average in the single digits and teens.


.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 300 AM MST Fri Feb 24 2017

Occasional MVFR cigs/MVFR-IFR vis in light snow/fog will continue
through early afternoon, then improve to VFR. The mountains will be
obscured. Surface winds will be north/northeast through this morning,
shifting to northwesterly this afternoon. Wind speeds will from 8 to
15 kt.


Issued at 300 AM MST Fri Feb 24 2017

Deep snow pack, along with cool/moist weather conditions will limit
fire weather concerns in the foreseeable future.


WY...Winter Storm Warning until 11 AM MST this morning for WYZ101>110-

NE...Winter Storm Warning until 11 AM MST this morning for NEZ002-003-

     Winter Weather Advisory until 11 AM MST this morning for NEZ054-



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