Special Weather Statement
Issued by NWS Riverton, WY

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WWUS85 KRIW 122021
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Special Weather Statement
National Weather Service Riverton WY
221 PM MDT Tue Sep 12 2017

WYZ001-002-012>015-023>027-131100-
Yellowstone National Park-Absaroka Mountains-
Teton and Gros Ventre Mountains-Jackson Hole-
Wind River Mountains West-Wind River Mountains East-Star Valley-
Salt River and Wyoming Ranges-Upper Green River Basin Foothills-
Upper Green River Basin-South Lincoln County-
Including the cities of Lake, Mammoth, Old Faithful, Jackson,
Afton, Alpine, Star Valley Ranch, Thayne, Pinedale, La Barge,
Big Piney, Farson, Kemmerer, and Cokeville
221 PM MDT Tue Sep 12 2017

|...Major Change To Cold and Wet Conditions Thursday Night Through
Saturday...
...Significant Mountain Snow Possible Friday into Saturday...

A cold storm system over the Gulf of Alaska will drop southeast
into the Great Basin later Thursday into Friday and swing east
across the area Friday night and Saturday. Widespread showers and
some thunderstorms are expected ahead of this system Thursday into
Thursday night. Only the highest peaks will see snow from the
first part of this storm. However, as a strong cold front moves in
Friday, much colder air will be ushered in along with falling
snow levels. Widespread rain will continue across the lower
elevations while snow levels fall from above 10,000 feet Thursday
night to at or near the valley and basin floors Friday night.
Significant mountain snow is expected over most of the western
mountains later Friday into Friday night as much colder air moves
in and snow levels lower. It`s quite possible that the western
mountains see 5 to 10 inches of snow with over a foot above
10,000 feet during this period. Even the Jackson Valley and Upper
Green River Basin Foothills could see a dusting of snow later
Friday night. The lower elevations of Western Wyoming could see
as much as one half to one and a half inches of rainfall from
Thursday through Saturday night.

Campers, hunters and other outdoor interests should keep abreast
of the latest developments on this first cold, wet, and white,
storm system of the pre-fall season. Some of the higher trails in
the mountains could be covered by a significant amount of snow
later Friday into Saturday. Pay attention to the latest forecast
and plan accordingly.

Freezing temperatures will likely impact much of the western
valleys and basins Sunday morning behind this system.

Stay tuned for further statements from your National Weather
Service office in Riverton.


$$

WYZ003>011-016>020-022-028>030-131100-
Cody Foothills-North Big Horn Basin-Southwest Big Horn Basin-
Southeast Big Horn Basin-Owl Creek and Bridger Mountains-
Bighorn Mountains West-Bighorn Mountains Southeast-
Northeast Johnson County-Southeast Johnson County-
Upper Wind River Basin-Wind River Basin-Lander Foothills-
Green Mountains and Rattlesnake Range-
Natrona County Lower Elevations-Casper Mountain-
Rock Springs and Green River-Flaming Gorge-East Sweetwater County-
Including the cities of Cody, Meeteetse, Thermopolis, Worland,
Buffalo, Kaycee, Dubois, Riverton, Shoshoni, Lander,
Jeffrey City, Casper, Rock Springs, Green River, and Wamsutter
221 PM MDT Tue Sep 12 2017

|...Major Change To Colder and Wet Conditions Thursday Night
Through Saturday...
...Significant Mountain Snow Possible Friday into Saturday...

A cold storm system over the Gulf of Alaska will drop southeast
into the Great Basin later Thursday into Friday and swing east
across the area Friday night and Saturday. Widespread showers and
some thunderstorms are expected ahead of this system Thursday into
Thursday night. Only the highest peaks will see snow from the
first part of this storm. However, as a strong cold front moves in
Friday, much colder air will be ushered in along with falling
snow levels. Widespread rain will continue across the lower
elevations while snow levels fall from above 10,000 feet Thursday
night lowering to between 6000 and 7000 feet Friday night and
Saturday morning. Significant snow is expected over Bighorn
mountains later Friday through Saturday as much colder air moves
in and snow levels lower. It`s quite possible that the Big Horn
mountains see 4 to 9 inches of snow with over a foot above 10,000
feet during this period. The lower elevations will see periods of
rain during this period, possibly mixing with or changing to snow
above 6,000 to 7000 feet late Friday night or early Saturday. The
lower elevations of Western Wyoming could see as much as one half
to one and a half inches of rainfall from Thursday through
Saturday night.

Campers, hunters and other outdoor interests should keep abreast
of the latest developments on this first cold, wet, and white,
storm system of the pre-fall season. Some of the higher trails in
the Big Horn mountains could be covered by a significant amount of
snow later Friday into Saturday. Pay attention to the latest
forecast and plan accordingly.

Freezing temperatures are also possible in the low lying areas Sunday
morning behind this system.

Stay tuned for further statements from your National Weather
Service office in Riverton.

$$

TEAM RIVERTON



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