Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 140522
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
1122 PM MDT Sun Aug 13 2017

.SHORT TERM...(This evening through Wednesday)
Issued at 204 PM MDT Sun Aug 13 2017

As a Pacific low pressure trough over British Columbia, the Pacific
Northwest and Northern California moves east into the Northern
Rockies and Great Basin, west southwest flow aloft will increase
across the area bringing pacific moisture and scattered showers and
thunderstorms to the area tonight and Monday.  Convection will be
strongest and most numerous over the western and northern mountains.
Small hail, strong wind gusts and locally heavy rain will be
possible. Tuesday the trough will pass through the area with
continued showers and thunderstorms with colder temperatures as a
cold front sweeps south and east.  Cooler and more stable air will
be over the area Wednesday with decreased shower and thunderstorm
activity.

.LONG TERM...(Wednesday night through Sunday)
Issued at 204 PM MDT Sun Aug 13 2017

As the Pacific trough moves east of the area Wednesday night and
Thursday, drying will occur.  Isolated showers and thunderstorms
will be possible in the north on Thursday, then a prolonged dry
period is expected Friday through Sunday with warming.  |

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday)
Issued at 1122 PM MDT Sun Aug 13 2017

Satellite imagery showing an upper trough across the Pacific
Northwest late Sunday evening. Embedded shortwaves are rotating east
and then northeast within the trough, with the next shortwave poised
to reach western Wyoming Monday morning. Jet streak accompanying
this shortwave will enhance precipitation across northwest Wyoming
by late Monday morning through the afternoon. While all terminals
will remain VFR, mountain top obscurations will become common across
the Teton and Gros Ventre ranges and north into Yellowstone by
18Z/Mon. Localized MVFR ceilings are possible in this region by late
afternoon as a cold front pushes in from the west. Showers and
thunderstorms will break-out elsewhere after about 20Z/Mon, with the
strongest storms to be along the east slopes of the Bighorn Range.
Main hazards will be brief heavy rain, small hail, and wind gusts of
35-45kts - similar to what was seen over the weekend. Winds at most
terminals will veer to a more northerly direction Monday evening as
the cold front pushes across the forecast area. Trend should be for
lowering ceilings after about 03Z/Tue.

&&

.FIRE WEATHER...
Issued AT 204 PM MDT Sun Aug 13 2017

As a Pacific low pressure trough over British Columbia, the Pacific
Northwest and Northern California moves east into the Northern
Rockies and Great Basin, west southwest flow aloft will increase
across the area bringing pacific moisture and scattered showers and
thunderstorms to the area tonight and Monday.  Convection will be
strongest and most numerous over the western and northern mountains.
Small hail, strong wind gusts and locally heavy rain will be
possible. Tuesday the trough will pass through the area with
continued showers and thunderstorms with colder temperatures as a
cold front sweeps south and east.  Cooler and more stable air will
be over the area Wednesday with decreased shower and thunderstorm
activity.  Afternoon mixing and transport winds will support very
good to excellent smoke dispersal through Wednesday.

&&

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

$$

SHORT TERM...Baker
LONG TERM...Baker
AVIATION...CNJ
FIRE WEATHER...Baker



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