Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 271131

Area Forecast Discussion
National Weather Service Cheyenne WY
531 AM MDT Thu Oct 27 2016

.SHORT TERM...(Today through Saturday)
Issued at 255 AM MDT Thu Oct 27 2016

Quiet weather will continue through Friday with some record high
temperatures likely across the region as 700mb temperatures
increase over 10c. Good mixing in the boundary layer for this
time of the year will result in highs in the 70`s across most of
southeast Wyoming to the low/mid 80`s over western Nebraska and
far eastern Wyoming. Lee-side surface trough will develop each
afternoon...which will keep winds breezy to locally windy west of
the I-25 corridor. Lighter winds are expected further east as
surface winds shift into the response to the lee- side
surface trough developing across the high plains of southeast

For Friday night and Saturday...all models show a weakening
shortwave trough lifting northeast across the Great Basin and into
Wyoming. Will have to monitor this feature over the next 48 hours
since it will contain some of the tropical moisture from
Hurricane Seymour. For appears most of the moisture will
slip to the north of the area across Montana and far northern
Wyoming. Only the Canadian model shows some moderate to heavy
rainfall extending from Douglas to Chadron Nebraska early
Saturday. Kept a chance of rain in the forecast in those
areas...and will continue to monitor the track of this system. The
other forecast concern will be winds across the wind prone areas
of southeast Wyoming Friday night as a weak cold front moves
towards the area. As of right appears the northern Snow
Range foothills between Rawlins and Laramie will be the most
likely location to see high winds with models showing the best
low-mid level subsidence and 700mb winds over 50 knots. Increased
winds between 25 to 35 mph for now with gusts over 50 mph
expected. May need High Wind headlines if this trend continues.
Otherwise...Saturday will be noticeably cooler especially further
north...with high temperatures in the 60`s to low 70`s.

.LONG TERM...(Saturday night through next Wednesday)
Issued at 224 AM MDT Thu Oct 27 2016

Saturday night/Sunday...Southwest flow aloft strengthens producing
windy conditions on Sunday after daybreak. Not a lot of moisture
yet, though by Sunday afternoon we may see isolated to scattered
showers across the Sierra Madre Range of southern Carbon county.
Continued quite mild on Sunday based on downslope winds and 700 mb
temperatures near 8 Celsius.

Monday...Fast moving shortwave progged to move into western Wyoming
in the morning then to western Nebraska by early afternoon and to
eastern South Dakota by Halloween evening. The associated cold front
will also quickly sweep across our counties, moving across our
entire forecast area by early afternoon. With the lack of low and
mid level moisture with this shortwave, the main effect will be
scattered showers over the mountains with quite windy conditions
especially after cold frontal passage. Downslope west winds will
limit precipitation coverage almost completely east of the
mountains. Cooler temperatures, though not cold, in the wake of the
cold front and quite windy in the afternoon and evening based on
progged gradients.

Tuesday...Dry and slightly cooler at most locations with southwest
flow aloft.

Wednesday...Next shortwave progged to move into western Colorado in
the afternoon with the models keeping the bulk of precipitation to
our south over Colorado. Thus will keep our forecast area dry. Cool
upslope east and southeast winds will prevail at the surface,
limiting potential warming.


.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 529 AM MDT Thu Oct 27 2016

VFR. Wind gusts from 23 to 35 knots across Wyoming TAF sites
from 16Z to 01Z.


Issued at 225 AM MDT Thu Oct 27 2016

Elevated Fire weather concerns are anticipated for a few hours
this afternoon...mainly along I-25 as humidities lower between 12
to 17 percent. Winds will become gusty west of I25 with gusts
between 25 to 35 mph possible. However...with the lee-side surface
trough developing further west this afternoon compared to
yesterday...expect the strongest winds to be west of the I-25
corridor where the best gradient will be located. Cancelled the
Fire Weather Watch since only a few locations are expected to
reach Red Flag criteria...mainly far western Converse county and
central Laramie and Platte counties. Otherwise...a cold front will
move southward across the area Friday night resulting in slightly
cooler temperatures and higher humidities for the weekend.




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