Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 311948
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
148 PM MDT TUE MAY 31 2016

.SHORT TERM...Tonight Through Wednesday

H8-H7 Frontogenesis/moisture is keeping a sc/cu deck over the
central zones as expected today. Next shortwave on the back side
of our ND upper low is pushing one more frontal boundary swd today
with strong wind across the nrn zones. This front will work swd
through the aftn before running out of steam in the sw this
evening. Weak convergence zone in Western Sweetwater could
interact with some afternoon cu over the Salt/Wyoming Ranges to
create a few showers into the evening hours over that area. Will
watch this cu development closely and see if we need any isold
showers added down there. Otherwise, a few mtn showers with the
north to northeast wind gradually diminishing overnight. Will have
to watch the overnight temps closely in the central zones for some
localized freezing temps. SPS issued for the Casper, Riverton,
Hudson, Lander area to cover possible low lying area frost early
Wednesday. Doesn`t look quite as good as a couple days ago with
some limited moisture hanging around in the lower levels and n-ne
wind staying up longer than optimal. Will still lower temps back
down to just above freezing in the low lying areas around Casper
and Riverton to Lander. On Wednesday, a ripple in the wly flow
skirts the north late in the day with a little moisture and weak
instability. Previous forecast already had some shower/tstm
potential in the far north and that still looks good. The warm-up
begins tomorrow with most areas east of the divide seeing about a
10 degree warm- up with 5 on average out west. Upper 60s to upper
70s across the lower elevations with 45 to 60 in the high country
depending on elevations.

.LONG TERM...Wednesday Night THROUGH Tuesday

A ridge of the desert southwest continues to bring mostly dry
conditions to the area for the early portion of the forecast period.
A zonal flow will be present through Thursday evening as a wave
moving through southern Canada flattens the flow around the
Intermountain West.

Ridging returns Friday morning, with amplification expected through
Saturday. Some moisture trapped within the arch of the ridge will
bring enough moisture to result in isolated showers and
thunderstorms Saturday afternoon and evening, especially over the
western mountains.  Warming temperatures expected to continue
through Thursday, with a quick cool-down anticipated on Friday and
Saturday.

An area of low pressure moving over central California will also
impact the flow around the ridge on Sunday morning and afternoon,
keeping moisture around for another round of afternoon showers and
storms.

Models continue to bring the area of low pressure over the desert
southwest through late Monday, causing it to become an open wave by
Tuesday afternoon. The movement of this system through the area will
keep showers and thunderstorms across the west through Tuesday
evening. Even with the influence of this area of low pressure,
temperatures will continue to warm through the latter portion of the
forecast period, with low to mid 80s possible early next week.

&&

.AVIATION.../00Z ISSUANCE/

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

VFR conditions to prevail for the region through Wednesday.
Isolated late day showers or thunderstorms are possible near
the Montana border Wednesday afternoon.

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

VFR conditions to prevail over the region through Wednesday.
Isolated showers or storms will form along the east slopes of the
Absaroka, Wind River, and Bighorn mountains this afternoon and
drift southeast over the adjacent lower elevations through 03z.
Expect gusty wind near storms and partial mountain obscuration.
Will keep the VCSH at KCOD terminal site through early evening.
Isolated late day showers or thunderstorms are possible again
Wednesday over the northern mountains.

&&

.FIRE WEATHER...

A few showers will be possible across the higher mountains of
central and northern WY thru early this evening. Wednesday will
herald the beginning of a warming/drying trend with high
temperatures reaching into the mid to upper 80s by the end of the
week. Winds through the end of the week will largely remain at or
below 15 mph for all locations. Isolated mainly late day
thunderstorms will creep back into the forecast by the weekend,
mainly over the mountains.

&&

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

&&

$$

SHORT TERM...PS
LONG TERM...Branham
AVIATION...PS
FIRE WEATHER...PS


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