First snow of the season coming; Best chance in Wind River Basin is Thursday and Friday

The Riverton National Weather Service radar dome pictured last winter. (County10.com file photo) 

(Riverton, Wy.) – The National Weather Service Office in Riverton said the first potentially significant snowfall may begin to fly as early as tonight. Much colder temperatures are anticipated for the latter half of the week, which may introduce snowfall across the majority of the forecast area. Areas west of the Continental Divide are expected to see the most significant snowfall out of the system, with the northwestern mountains favorable to receive the first significant snowfall of the season.

The Hazardous Weather Outlook and a Special Weather Statement  from the NWS are copied below:

...WINTER STORM WATCH LATE TONIGHT THROUGH WEDNESDAY NIGHT FOR THE
NORTHWEST MOUNTAINS...

...RED FLAG WARNING FOR FIRE WEATHER ZONE 280 THIS AFTERNOON...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING.

.DAY ONE...TODAY AND TONIGHT

INCREASING CHANCES FOR SHOWERS WITH PERHAPS AN EMBEDDED THUNDERSTORM
OR TWO WILL BEGIN IN THE WESTERN FORECAST ZONES THIS EVENING.
AFTER MIDNIGHT TONIGHT...A SIGNIFICANT PERIOD SNOWFALL WILL BE
POSSIBLE...IN THE HIGHER ELEVATIONS OF THE WEST...WITH
SNOW LEVELS BEGINNING AROUND 9000 FEET...BEFORE LOWERING TO 7500
FEET BY WEDNESDAY MORNING.

EXTREME FIRE WEATHER CONDITIONS ACROSS MUCH OF NATRONA COUNTY THIS
AFTERNOON.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

PERIODS OF MODERATE TO HEAVY SNOWFALL WILL BE POSSIBLE ACROSS
MOUNTAINS OF THE WEST AND NORTHWEST FORECAST AREA...WITH SNOW
LEVELS LOWERING TO NEARLY 5000 FEET BY WEDNESDAY NIGHT...BRINGING 2
TO 4 INCHES ACROSS A WIDE AREA...AND UP TO A FOOT IN THE HIGHER
MOUNTAINS ABOVE 7500 FEET.

THURSDAY AND FRIDAY...SIGNIFICANT SNOWFALL IS POSSIBLE
ACROSS THE CENTRAL AND SOUTHWEST MOUNTAINS ALONG WITH THE FAVORED
UPSLOPE AREAS LIKE THE LANDER FOOTHILLS.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RIVERTON WY
252 AM MDT TUE SEP 24 2013

WYZ013>015-023>030-242200-
EAST SWEETWATER COUNTY-FLAMING GORGE-JACKSON HOLE-
ROCK SPRINGS AND GREEN RIVER-SALT RIVER AND WYOMING RANGES-
SOUTH LINCOLN COUNTY-STAR VALLEY-UPPER GREEN RIVER BASIN-
UPPER GREEN RIVER BASIN FOOTHILLS-WIND RIVER MOUNTAINS EAST-
WIND RIVER MOUNTAINS WEST-
252 AM MDT TUE SEP 24 2013

...ACCUMULATING SNOWFALL POSSIBLE THURSDAY AND FRIDAY...

A MAJOR STORM SYSTEM IS TAKING SHAPE FOR WEDNESDAY THROUGH FRIDAY
ACROSS THE AREA. ON WEDNESDAY...IT WILL BE MAINLY THE FAR NORTHWEST
SECTIONS THAT WILL SEE STEADY TO SIGNIFICANT PRECIPITATION WITH
SOME SNOW IN THE MOUNTAINS. A SECOND STORM SYSTEM WITH COLDER AIR
WILL DEVELOP TO OUR SOUTHWEST ON THURSDAY AND MOVE ACROSS THE AREA
INTO FRIDAY. THE BEST CHANCE OF SNOWFALL WILL BE THURSDAY INTO FRIDAY
MORNING ACROSS THE SOUTHWEST. SNOW LEVELS WILL START OUT AROUND 9500
FEET WEDNESDAY MORNING AND LOWER TO AROUND 7000 FEET WEDNESDAY
AFTERNOON IN THE NORTHERN PART OF THE AREA. EVEN COLDER AIR WILL BE
USHERED IN THURSDAY INTO THURSDAY NIGHT WITH ALL AREAS EXPECTED TO
SEE A RAIN TO SNOW CHANGEOVER. POTENTIALLY HEAVY SNOW IS POSSIBLE IN
THE WIND RIVER MOUNTAINS...ESPECIALLY THE EAST SLOPES INCLUDING SOUTH
PASS AND THE EAST SLOPE OF THE WYOMING RANGE. ANOTHER AREA OF HEAVY
SNOW COULD DEVELOP FROM NEAR KEMMERER TO FARSON. SNOWFALL OF 4 TO 8
INCHES IS POSSIBLE IN THE MOUNTAINS WITH LOCALLY HIGHER AMOUNTS ON
THE EAST SLOPE OF THE WIND RIVER MOUNTAINS. THE LOWER ELEVATIONS WILL
VARY FROM 1 TO 4 INCHES WITH LOCALLY HIGHER AMOUNTS FROM KEMMERER TO
FARSON LATER THURSDAY INTO FRIDAY MORNING.