Winter Storm in Wyoming, January 11, 2007

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
828 PM MST WED JAN 10 2007

UPDATED...ADDED SOUTHERN BIG HORN BASIN TO SNOW ADVISORIES.

.SHORT TERM...SW FLOW WILL CONTINUE ALOFT OVER THE FORECAST AREA
TONIGHT AND THURSDAY AS AN UPPER LEVEL TROF MOVES INTO THE NW U.S.
PVA WILL OCCUR OVER THE WESTERN AND NORTHER PORTIONS OF THE CWA
TONIGHT AND THURSDAY...AS PIECES OF ENERGY EJECT OVER THE AREA.  AT
THE SURFACE...COLD FRONT WILL MOVE SOUTH OF THE AREA TONIGHT.
UPSLOPE FLOW WILL DEVELOP ON THE LEE SIDE OF THE MOUNTAINS.  6 TO 10
INCHES OF NEW SNOW WILL FALL BY THURSDAY AFTERNOON IN THE NORTHWEST
MOUNTAINS...WITH 3 TO 6 INCHES AT THE LOWER ELEVATIONS OF THE
NORTH.  WILL GO WITH A SNOW ADVISORY FOR THIS AREA FOR TONIGHT AND
THURSDAY.  WINDS SHOULD DECREASE THIS EVENING...SO PLAN ON LETTING
THE HIGH WIND WARNING EXPIRE AT 00Z.

.LONG TERM...UPPER TROUGH WILL CONTINUE TO IMPACT SOUTH AND EAST
PORTION OF THE REGION ON SATURDAY. MODELS STILL VARYING ON HOW
QUICKLY THE SYSTEM MOVES OUT OF THE AREA. WILL CONTINUE WITH LIGHT
SNOW CHANCE IN THE SOUTH AND EAST ZONES ON SATURDAY. LITTLE CHANGES
MADE IN THE EXTENDED FORECAST. A SERIES OF SHORTWAVES MOVE ACROSS
THE REGION WITH THE FIRST MOVING IN ON SUNDAY. WILL CONTINUE WITH
CHANCE OF SNOW SHOWERS ACROSS NORTHWEST PORTIONS OF THE COUNTY
WARNING AREA. A BREAK IN IN SNOW FOR LOWER ELEVATIONS ON
MONDAY...WITH ONLY A SLIGHT CHANCE FOR THE HIGHER ELEVATIONS.
EXPECT SOME MODERATION IN TEMPERATURES ON TUESDAY AND WEDNESDAY NEXT
WEEK WHEN SOME MIXING WILL OCCUR. SOME VALLEYS MAY STRUGGLE AS THE
INVERSION LIMITS WARMING.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
    SNOW ADVISORY IN EFFECT 5PM TONIGHT THROUGH 5 PM THURSDAY FOR
    WYOMING ZONES 1...12 AND 13.
    SNOW ADVISORY IN EFFECT 11 PM TONIGHT THROUGH 11 PM THURSDAY
    FOR WYOMING ZONES 2-4 AND 8-11.
    SNOW ADVISORY IN EFFECT 5 AM THURSDAY THROUGH 5 AM FRIDAY FOR
    WYOMING ZONES 5-7.

&&

SHORT TERM...KMD/AEM
LONG TERM...MG

LONG TERM...MG

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE RIVERTON WY
400 PM MST WED JAN 10 2007

WYZ001>020-022>030-111300-
ABSAROKA MOUNTAINS-BIGHORN MOUNTAINS SOUTHEAST-
BIGHORN MOUNTAINS WEST-CASPER MOUNTAIN-CODY FOOTHILLS-
EAST SWEETWATER COUNTY-FLAMING GORGE-
GREEN MOUNTAINS AND RATTLESNAKE RANGE-JACKSON HOLE-LANDER FOOTHILLS-
NATRONA COUNTY LOWER ELEVATIONS-NORTH BIG HORN BASIN-
NORTHEAST JOHNSON COUNTY-OWL CREEK AND BRIDGER MOUNTAINS-
ROCK SPRINGS AND GREEN RIVER-SALT RIVER AND WYOMING RANGES-
SOUTH LINCOLN COUNTY-SOUTHEAST BIG HORN BASIN-
SOUTHEAST JOHNSON COUNTY-SOUTHWEST BIG HORN BASIN-STAR VALLEY-
TETON AND GROS VENTRE MOUNTAINS-UPPER GREEN RIVER BASIN-
UPPER GREEN RIVER BASIN FOOTHILLS-UPPER WIND RIVER BASIN-
WIND RIVER BASIN-WIND RIVER MOUNTAINS EAST-WIND RIVER MOUNTAINS WEST-
YELLOWSTONE NATIONAL PARK-
400 PM MST WED JAN 10 2007

...SNOW ADVISORY FOR YELLOWSTONE NATIONAL PARK...TETON AND GROS
VENTRE MOUNTAINS IN EFFECT FROM 5 PM MST TONIGHT THROUGH THURSDAY AT
5 PM MST...
...SNOW ADVISORY FOR NORTH CENTRAL PORTIONS OF WYOMING INCLUDING THE
BIGHORN MOUNTAINS AND BASIN IN EFFECT FROM 11 PM MST TONIGHT THROUGH
THURSDAY AT 11 PM MST...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING.

.DAY ONE...TODAY AND TONIGHT

A STRONG ARCTIC COLD FRONT WILL MOVE ACROSS CENTRAL AND WESTERN
WYOMING TONIGHT THROUGH THURSDAY. PERIODS OF SNOW WILL DEVELOP
TONIGHT INITIALLY ACROSS FAR NORTHWEST WYOMING AND THEN SPREAD
ACROSS NORTH CENTRAL WYOMING. A SNOW ADVISORY WILL BE IN EFFECT
ACROSS YELLOWSTONE NATIONAL PARK...TETON AND GROS VENTRE MOUNTAINS
AT 5 PM TONIGHT THROUGH THURSDAY. SNOW WILL BEGIN TO FALL ACROSS
NORTH CENTRAL PORTIONS OF WYOMING THAT INCLUDES THE BIGHORN
MOUNTAINS AFTER 11 PM TONIGHT AND CONTINUE THROUGH THURSDAY NIGHT.
BY THURSDAY MORNING EXPECT SNOW ACCUMULATIONS OF 1 TO 3 INCHES IN
THE LOWEST ELEVATIONS AND 2 TO 4 INCHES IN THE HIGHER TERRAIN.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

A COLD ARCTIC AIRMASS WILL PUSH SOUTH ACROSS THE STATE THURSDAY AND
FRIDAY SPREADING SNOW ACROSS MOST OF WEST AND CENTRAL WYOMING.
INITIALLY THE SNOW WILL FALL ON WARM ROAD SURFACES EARLY THURSDAY
MORNING ACROSS CENTRAL WYOMING...RESULTING IN ROADS AND HIGHWAYS
BECOMING ICY AND EXTREMELY SLICK...ESPECIALLY DURING THE MORNING
COMMUTE.

SNOW ADVISORY CONTINUES IN EFFECT FOR BOTH FAR NORTHWEST WYOMING AND
NORTH CENTRAL WYOMING ON THURSDAY. EXPECT TOTAL SNOWFALL
ACCUMULATIONS OF 3 TO 6 INCHES IN THE LOWER ELEVATIONS AND 6 TO 12
INCHES IN THE HIGHER TERRAIN.

STRONG NORTHEAST WINDS WILL DEVELOP BEHIND THIS COLD FRONT...
ESPECIALLY OVER SOUTH PASS...THE RED DESERT...THE INTERSTATE 80
CORRIDOR AND ACROSS THE SOUTHWEST CORNER OF WYOMING. THESE STRONG
NORTHEAST WINDS COMBINED WITH SNOWFALL MAY MAKE TRAVEL TREACHEROUS
THURSDAY AND INTO FRIDAY.

WELL BELOW AVERAGE TEMPERATURES WILL OCCUR FRIDAY THROUGH THE WEEKEND
AS THE ARCTIC AIR BECOMES ENTRENCHED OVER THE REGION. OVERNIGHT
LOWS WILL LIKELY PLUMMET WELL BELOW ZERO IN MANY LOCALES SATURDAY
AND SUNDAY MORNINGS. EVEN NEXT MONDAY LOOKS TO BE QUITE COLD NOW.
OVERNIGHT LOWS SATURDAY AND SUNDAY MORNING WILL LIKELY RANGE FROM
-10 TO -20 BELOW ZERO IN THE EAST AND MOUNTAIN LOCATIONS WITH -25
TO -35 BELOW ZERO ACROSS THE FAR WEST VALLEYS AND BASINS.

ANYONE WITH OUTDOOR PLANS THURSDAY INTO THE COMING WEEKEND SHOULD BE
PREPARED FOR HARSH WINTER WEATHER CONDITIONS. NOW IS THE TIME TO
FINISH PREPARATIONS FOR THIS ONSLAUGHT OF WINTER WEATHER.

SPOTTER INFORMATION STATEMENT...

SPOTTERS ARE ENCOURAGED TO REPORT ANY SUSTAINED WIND SPEEDS OVER 40
MPH OR WIND GUSTS OVER 60 MPH.