Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 130556
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
1156 PM MDT Thu Oct 12 2017

.SHORT TERM...(This evening through Sunday)
Issued at 150 PM MDT Thu Oct 12 2017

High pressure will be over the area tonight.  A Pacific low pressure
trough will move east bringing increased snow shower activity over
northwest mountain areas through Friday and Friday night.  Northwest
mountains can expect 3 to 6 inches of snow with local 8 inches above
9500 feet.  1 to 3 inches of snow possible in the northwest valleys.
Along and east of the east slopes of the mountains downslope winds will
increase becoming windy in the Absaroka, Bighorn and Wind River foothills
extending across Natrona county. A cold front will move through the area
with the Pacific trough on Saturday with colder temperatures and decreasing
snow showers and wind through the day Saturday.  Saturday night and Sunday
are expected to be dry and cold with high pressure over the area.

.LONG TERM...(Sunday night through Thursday)
Issued at 150 PM MDT Thu Oct 12 2017

Synopsis...Zonal flow/flat ridging pattern will be in place through
much of the period next week. A dry cold front will quickly pass
through the area Wednesday, with major changes coming to the area by
Thursday. Models continue to differ Betteann either a strong zonal
Pacific jet moving over the forecast area by Thursday or a digging
longwave trough coming onshore over the PACNW. Kept a chance of PoPs
over the far west Thursday night, as models trend toward some sort
of precip during that time.

Discussion...Temperatures continue to trend just slightly above
normal Tuesday and Wednesday. Have bumped highs on these days
slightly, but could see many areas east of the Divide 5 to 10
degrees warmer than current guidance is indicating.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1155 PM MDT Thu Oct 12 2017

VFR conditions will prevail across the area through 18z Saturday.
Areas of LLWS will increase along the east slopes of the Divide,
vcnty KCOD-KDUB-KLND 15z-18z Saturday, ahead of an approaching cold
front.  This cold front will bring scattered to numerous snow
showers into the northwest mountains, vcnty and north of a KJAC-KDUB
line, Saturday afternoon with increasing mountain obscurations.
Surface SW winds will increase to 15-25 knots across much of
southern and central Wyoming around 18z Saturday.  The cold front
will push SE across the rest of the area 00z-06z Sunday spreading
sct MVFR/IFR valley and numerous mountain snow showers across the
area.  The main band of MVFR/IFR snow showers are expected to be
centered roughly along a vicinity KAFO-KRIW-KCPR line 09z-12z
Sunday.

&&

.FIRE WEATHER...
Issued AT 150 PM MDT Thu Oct 12 2017

High pressure will be over the area tonight.  A Pacific low pressure
trough will move east bringing increased snow shower activity over
northwest mountain areas through Friday and Friday night.  Along and
east of the east slopes of the mountains downslope winds will increase
becoming windy in the Bighorn and Wind River foothills extending across
Natrona county. A cold front will move through the area with the Pacific
trough on Saturday with colder temperatures and decreasing snow showers
and wind through the day Saturday.  Saturday night and Sunday are
expected to be dry and cold with high pressure over the area.  Windy areas
will have the best chances for good or better smoke dispersal while the
northwest with snowfall, and the deep narrow valleys in the mountains
will have poor smoke dispersal with temperature inversions.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Baker
LONG TERM...LaVoie
AVIATION...Meunier
FIRE WEATHER...Baker



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