Area Forecast Discussion
Issued by NWS Cheyenne, WY

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863
FXUS65 KCYS 222348 CCA
AFDCYS

Area Forecast Discussion...Corrected Aviation
National Weather Service Cheyenne WY
543 PM MDT THU SEP 22 2016

.SHORT TERM...(This evening through Saturday)
Issued at 215 PM MDT Thu Sep 22 2016

Unsettled weather expected across the CWA for the next couple
days as an upper low currently over northwestern Nevada moves
east across Utah overnight then turns northeast across western
Wyoming Friday and on to the far northern high plains Saturday.
A mixed bag of weather will occur over the CWA as this system
progresses. For tonight a band of showers will continue to move
NNE across western Carbon county as some shortwave energy lifts
across that area ahead of the upper low. Should be a lull in
activity there later tonight while over the plains of far
southeast Wy into the Panhandle low clouds and patchy fog/drizzle
persist in moist upslope flow though maybe not as much fog as
surface wind direction not quite as favorable.

A surface boundary will edge east over the high plains Friday
while a cold front moves into central Wyoming. Should see
convection increase over the eastern plains of Wyoming Friday
afternoon and move east over the Panhandle Friday evening. A few
stronger storms not out of the question mainly over the Panhandle
given decent forcing and strong mid-level winds. Cold front will
sweep across the plains Friday evening with most pcpn clearing out
east of the mtns as the air mass dries and winds turn downslope.
Snow showers should occur later Friday night into Saturday morning
over the higher mtns as moisture rounding the southern part of the
upper low rides up the west slopes. Saturday looking breezy/windy
along with cooler temps. Could see a brief period of stronger
winds around the mtns of southeast Wyoming Saturday morning as
700H wind progged near 50kts for a short time but the threat for
high winds looks marginal both in space and time. Widely
scattered showers continuing through the day Saturday mainly
around the mtns.

.LONG TERM...(Saturday night through Thursday)
Issued at 215 PM MDT Thu Sep 22 2016

Kept some lingering PoPs going for mostly showers along and west
of the Laramie Range with periodic snow showers in the Sierra
Madre and Snowy Ranges Saturday night, then tapered PoPs down
quickly Sunday morning as the main upper trough and forcing move
east of our area. Cool, dry and moderately breezy period expected
Sunday into Monday as we remain on the northeastern side of the
upper ridge under deeply dry northwesterly flow aloft. Then we see
a bit of a warmup Tuesday through Thursday as the upper ridge
builds in from the west. Overall fairly uneventful period expected
for the first full week of Fall.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 535 PM MDT Thu Sep 22 2016

Sct SHRA/isold TSRA will continue to develop and move quickly
north across areas west of the Laramie Range tonight. Included TEMPO
for MVFR cig/vis with -TSRA at RWL thru 03Z, then VCSH thru 15Z.
Also could have a few -SHRA invof LAR thru 03Z. Otherwise, primary
aviation concern will be deteriorating cigs/vis in low stratus and
fog east of the Laramie Range later this evening thru Fri morning
with moist east-southeast upslope flow. LIFR conditions forecast for
CYS, CDR, AIA, BFF and SNY mainly between 06Z and 15Z, with gradual
improvement to MVFR after 17Z. Southerly winds gusting to 30 kt will
develop at RWL, AIA and SNY, with lighter winds elsewhere.

&&

.FIRE WEATHER...
Issued at 215 PM MDT Thu Sep 22 2016

Fire weather concerns expected to remain low through the weekend
with weather conditions trending towards cooler and more moist. A
cold front will move east across the area Friday afternoon and
evening bringing scattered to numerous showers and a few storms
into Friday evening. Cool and breezy to windy conditions on
Saturday.

&&

.CYS Watches/Warnings/Advisories...
WY...None.
NE...None.
&&

$$

SHORT TERM...RE
LONG TERM...JG
AVIATION...MAJ
FIRE WEATHER...RE



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