Area Forecast Discussion
Issued by NWS Riverton, WY

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000
FXUS65 KRIW 292125
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
325 PM MDT THU SEP 29 2016

.Short Term...Tonight THROUGH Friday

South southwest flow moving up from the great basin will bring
increased moisture and mild air over western and central Wyoming.
This will result in increased shower and thunderstorm activity
to the area this evening through Friday.  The best chance for
precipitation will be in the mountains.

.Long Term...Friday Night Through Thursday

Showers and thunderstorms with some high elevation snow in the
mountains will continue through the weekend.  Then a large upper
level cut off low pressure storm system will move across the
area bringing widespread showers with mountain snow down to 9000
feet. Temperatures will cool. The extended models show
significant differences with the location of the low and these
differences significantly impact the amount of moisture this low
will bring to the area. by Monday night the gfs places the low in
southwest Utah while the ECMWF places the low near Buffalo
Wyoming. They do converge by Wednesday morning with the GFS low
around Sydney Nebraska and the ECMWF in south central South
Dakota. the forecast drys out Wednesday night and Thursday as both
models move the low east and bring a Pacific high pressure ridge
in from the west. There is little information at this time on
which model will verify better so a blend is preferred. Major
changes in the models will likely occur over the next 24 hours.

&&

.Aviation.../00Z Issuance/

West of the Continental Divide...KJAC/KBPI/KPNA/KRKS

Showers and isolated thunderstorms will continue through around 02z
with showers then persisting into the overnight hours. Gusty wind
will be possible at area terminals from nearby developing storms.
Showers and related MVFR to IFR conditions are possible at all area
terminals. Shower activity will weaken through the overnight hours,
with isolated mountain showers expected after 12z Friday, increasing
to scattered after 18z Friday. With the ongoing threat of shower
activity, periods of mountain obscurations are expected through the
TAF period.

East of the Continental Divide...KCOD/KCPR/KLND/KRIW/KWRL

Mountain showers and thunderstorms expected through the evening.
Storms may move off the mountains over KCOD and KLND, with periods
of gusty wind and VCTS possible. After 00z, additional isolated
showers may move east of the divide, impacting KCPR and KWRL where
VCSH have been included. MVFR conditions possible when storms are
present. Otherwise, generally VFR conditions expected with lowered
ceilings possible through 12z. Mountain obscurations will be
possible from ongoing shower threats.

&&

.Fire Weather...

South southwest flow moving up from the great basin will bring
increased moisture and mild air over western and central Wyoming.
This will result in increased shower and thunderstorm activity
to the area this evening through Friday.  The best chance for
precipitation will be in the mountains. Relative humidity will be
elevated through the weekend with some cooling.

&&

.RIW Watches/Warnings/Advisories...
None.
&&

$$

SHORT TERM...C.Baker
LONG TERM...C.Baker
AVIATION...Branham
FIRE WEATHER...C.Baker



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