Strong mountain top winds descended the east slope of the Absaroka Range west of Clark. Sustained wind along State Highway 296 on Chief Joseph Pass topped out at 63 mph at 1540MST.
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The episode as NWS RIW wrote it up.
Strong mountain top winds descended the east slope of the Absaroka Range west of Clark. Sustained wind along State Highway 296 on Chief Joseph Pass topped out at 63 mph at 1540MST.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Riverton, WY wrote its last area forecast discussion before the first event at Dec 31, 2:57 AM MST, 11 hours 53 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RIVERTON WY 257 AM MST WED DEC 31 2008 .SHORT TERM...TODAY THROUGH FRIDAY NIGHT ACTIVE PATTERN SHAPING UP WITH NEXT SYSTEM APPROACHING THE PAC NORTHWEST WITH NOSE OF STRONG JET (150KT+) HEADING INTO THE NORTHERN INTERMOUNTAIN WEST THIS MORNING. FIRST CONCERN WITH THIS WILL BE THE WINDS WHERE THE RFQ OF JET WILL APPROACH TODAY...ESPECIALLY OVER THE ABSAROKAS. NAM AND WRF SHOWING 50-60KT WINDS AT H7 OR MOUNTAIN TOP ALONG THE EAST SLOPES OF THE ABSAROKAS FROM 15Z THROUGH 03Z...AND EVEN LINGERING A BIT PAST. EXPECT TO SEE SUSTAINED WINDS AT SUMMITS AND PASSES OF 50 TO 60 MPH WITH GUST TO 90 MPH. WILL UPGRADE WATCH TO WARNING AT ISSUANCE FROM 8 AM THROUGH 8 PM THIS EVENING. MODEL SOUNDINGS DO SHOW A STABLE LAYER...AN INVERSION...BUT LIES AROUND H75 AND IS BELOW MOUNTAIN TOP...SO DONT EXPECT ANY MOUNTAIN WAVE ACTIVITY ALONG THE CODY FOOTHILLS INCLUDING CLARK. THATS NOT TO SAY THESE LOCATIONS WONT BE WINDY TODAY. MOST OTHER AREAS IN THE WEST AND CENTRAL TO BE QUITE WINDY AS WELL. EVEN EXPECT THE WIND RIVER BASIN AND BIG HORN BASIN TO MIX SOME TODAY. SECOND CONCERN WILL BE THE HEAVY SNOW POTENTIAL FOR THE WEST BEGINNING THIS AFTERNOON IN THE NORTHWEST. ISENTROPIC LIFT INCREASES TODAY...ESPECIALLY IN THE NORTHWEST WITH LIGHT SNOW DEVELOPING. THE SNOW WILL INCREASE IN INTENSITY THIS EVENING AS MOISTURE INCREASES AND CONDENSATION PRESSURE DEFICITS BECOME SATURATED. WILL ALSO HAVE RRQ JET DYNAMICS OVERNIGHT AS THE SHORTWAVE PASSES TO THE NORTH. THE SNOW SPREADS SOUTH INTO THE REMAINING AREA OF THE WEST OVERNIGHT BECOMING WIDESPREAD BY MORNING AS WELL. FIRST SHORTWAVE PASSES TONIGHT...THOUGH THERE WONT BE MUCH...IF ANY BREAK IN THE SNOW...AS ISENTROPIC LIFT RETURNS...STRONGER THAN TONIGHT. THIS CONTINUES THURSDAY AND THURSDAY NIGHT. THEN AS THE TROUGH APPROACHES...THE ISENTROPIC LIFT GIVES WAY TO BAROCLINIC LEAF DYNAMICS. THE TROUGH MOVES THROUGH FRIDAY NIGHT WITH ASSOCIATED COLD FRONT AHEAD OF IT. THE PRECIPITATION WILL RAPIDLY TAPER BEHIND THE TROUGH. WILL LIKELY SEE DECENT SNOWFALL RATES OF 1/2 TO 1 INCH PER HOUR IN THE FAR WEST THROUGH THIS PERIOD...AND POSSIBLY IN THE REMAINDER OF THE WEST. WILL START OFF THE FAR WEST WITH WINTER STORM WATCHES...STARTING THE NORTHWEST...YNP...TETONS AND JACKSON HOLE AT 6 PM THIS EVENING AND THE SALT/WYOMING RANGES...STAR VALLEY AND BONDURANT AT 6 AM THURSDAY. WIND RETURNS DURING THIS PERIOD AS WELL SO COULD BE NEEDING SOME HIGHLIGHTS FOR THE ABSAROKAS AND POSSIBLY DUBOIS...NATRONA AND SOUTHEAST FREMONT COUNTIES. COLD FRONT MOVES THROUGH FRIDAY SPREADING THE SNOW EAST OF THE DIVIDE. NOT LOOKING IMPRESSIVE AT THIS POINT...BUT WILL CONTINUE TO MONITOR THIS. .LONG TERM...SATURDAY THROUGH WEDNESDAY CYCLONIC FLOW ASSOCIATED WITH UPPER LOW TO OUR NORTH WILL PERSIST THROUGH MUCH OF SATURDAY WITH COLDER AIR FILTERING SOUTH THROUGH THE STATE. BEST SNOW CHANCES WILL REMAIN ACROSS THE NORTHERN MOUNTAINS AND WILL DIMINISH FROM WEST TO EAST DURING THE DAY. ENOUGH COLD AIR ASSOCIATED WITH THERMAL TROUGH TO KEEP MOSTLY CLOUDY SKIES ACROSS THE NORTH. IMPROVING CONDITIONS FOR SATURDAY NIGHT AS FLOW TRANSITIONS TO A SPLIT FLOW PATTERN. THIS LEAVES WYOMING BETWEEN SYSTEMS SATURDAY NIGHT AND SUNDAY. SATURDAY NIGHT WILL BE THE COLDEST MORNING OF THE EXTENDED PERIOD WITH CLEARING SKIES ALLOWING FOR BEST RADIATIONAL COOLING. STILL COLD FOR SUNDAY EVEN WITH SUNSHINE MORE PREVALENT...BUT SUNDAY SHOULD BE THE LEAST ACTIVE DAY ACROSS WESTERN AND CENTRAL WYOMING. UPPER LOW TRACKS THROUGH THE SOUTHERN PRAIRIE PROVINCES AND INTO THE GREAT LAKES SUNDAY AS SOUTHWEST LOW IS DRIVEN DEEP INTO THE DESERT SOUTHWEST BY 120KT JET. UPSTREAM KICKER REACHES THE BRITISH COLUMBIA COAST BY 12Z/MONDAY. WARM AIR ADVECTION PRECIPITATION IN ADVANCE OF THIS SYSTEM WILL REACH WESTERN WYOMING MONDAY AFTERNOON AND WITH IT A RETURN OF MOUNTAIN SNOW. WARM AIR ADVECTION WILL HELP TO BOOST TEMPERATURES SIGNIFICANTLY EAST OF THE DIVIDE ON MONDAY AND TUESDAY. OTHER FACTOR AIDING WARMUP WILL BE FORMATION OF LEE TROUGH ACROSS EASTERN WYOMING. THIS WILL BRING THE RETURN OF GUSTY SOUTHWEST WIND IN THE WIND CORRIDOR FROM ROCK SPRINGS TO CASPER...PARTICULARLY ON MONDAY. FLOW VEERS MORE TO THE NORTHWEST ON TUESDAY IN RESPONSE TO BUILDING RIDGE OFF THE WESTERN U.S. COAST. SHOULD STILL BE ENOUGH MOISTURE IN THIS FLOW TO GENERATE SNOW IN THE WEST. HOWEVER...RIDGE AXIS MOVES FAR ENOUGH INLAND TO PROVIDE MORE INFLUENCE FROM ANTICYCLONIC FLOW AND HAVE DECREASED SNOW CHANCES FROM MONDAY TO TUESDAY. FLOW TRANSITIONS BACK TO A MORE WESTERLY FLOW ON WEDNESDAY AS RIDGE FOLDS. HAVE ADDED CLIMATOLOGICAL CHANCE OF PRECIPITATION TO WEDNESDAY ACCORDINGLY. && .AVIATION... MOISTURE WILL CONTINUE TO INCREASE IN ZONAL WESTERLY FLOW PRODUCING INCREASED SNOWFALL IN THE WESTERN MOUNTAINS WITH SPREADING MVFR AND IFR CEILINGS AND VISIBILITIES PRODUCING MOUNTAIN OBSCURATIONS. CONDITIONS OVER THE MAJOR WESTERN VALLEYS ARE EXPECTED TO REMAIN VFR TO MVFR THROUGH THE AFTERNOON THEN DETERIORATE THROUGH THE NIGHT. EAST OF THE CONTINENTAL DIVIDE MID AND HIGH CLOUDS WILL INCREASE WITH STRONG WINDS DEVELOPING IN AN NEAR THE MOUNTAINS AND THROUGH THE WIND CORRIDOR FROM KRKS THROUGH KCPR. STRONG WIND GRADIENTS WILL PRODUCE AREAS OF LOW LEVEL WIND SHEAR. && .FIRE WEATHER... ZONAL FLOW ALOFT WILL BRING STRONG WINDS TO MANY LOCATIONS ACROSS THE AREA THROUGH THE END OF THE WEEK. WINDS TODAY IN THE ABSAROKAS COULD GUST AS HIGH AS 90 MPH. LIGHT SNOW WILL DEVELOP IN THE WEST TODAY AND CONTINUE HEAVY AT TIMES THROUGH FRIDAY EVENING. THE SNOW WILL SHIFT EAST OF THE DIVIDE TONIGHT AND ESPECIALLY FRIDAY. && .RIW WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING FROM 8 AM THIS MORNING TO 8 PM MST THIS EVENING FOR WYZ002. WINTER STORM WATCH FROM THURSDAY MORNING THROUGH FRIDAY AFTERNOON FOR WYZ023>025. WINTER STORM WATCH FROM THIS EVENING THROUGH FRIDAY AFTERNOON FOR WYZ001-012-013. && SHORT TERM...TWB LONG TERM...CNJ AVIATION...C.BAKER FIRE WEATHER...TWB
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RIVERTON WY 500 AM MST WED DEC 31 2008 WYZ001>020-022>030-011400- 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- 500 AM MST WED DEC 31 2008 ...HIGH WIND WARNING FOR THE ABSAROKA MOUNTAINS 8 AM TO 8 PM TODAY... ...WINTER STORM WATCHES IN EFFECT FOR MUCH OF FAR WESTERN WYOMING TONIGHT THROUGH FRIDAY AFTERNOON... THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING. .DAY ONE...TODAY AND TONIGHT VERY STRONG WEST WINDS ARE EXPECTED IN THE ABSAROKA MOUNTAINS TODAY. WEST WINDS WILL INCREASE RAPIDLY THIS MORNING...REACHING SPEEDS OF 45 TO 55 MPH WITH GUSTS AS HIGH AS 90 MPH. THESE WINDS WILL IMPACT TRAVEL ALONG THE CHIEF JOSEPH HIGHWAY NORTHWEST OF CODY. CONSIDERABLE BLOWING AND DRIFTING SNOW WILL ACCOMPANY THE WINDS ALONG HIGHWAY 296...THE CHIEF JOSEPH SCENIC HIGHWAY. MOST OTHER LOCATIONS ACROSS WEST AND CENTRAL WYOMING WILL EXPERIENCE WINDS TODAY. THE WINDS WILL BE QUITE GUSTY IN THE MOUNTAINS AS WELL AS NEAR CODY...DUBOIS...AND IN NATRONA AND SOUTHEAST FREMONT COUNTIES. THE NEXT IN A SERIES OF STORMS IS EXPECTED TO BRING HEAVY SNOW TO THE WEST BEGINNING IN THE NORTHWEST THIS EVENING. THE SNOW WILL BECOME MORE WIDESPREAD TONIGHT OVER JACKSON HOLE...THE TETONS AND YELLOWSTONE NATIONAL PARK. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY THE SNOW IS EXPECTED TO INTENSIFY THURSDAY MORNING AND SPREAD ACROSS THE REMAINDER OF THE WEST. THE SNOW MAY BECOME HEAVY AT TIMES... ESPECIALLY LATER THURSDAY AND THURSDAY NIGHT. GUSTY WINDS WILL ACCOMPANY THE SNOW RESULTING IN CONSIDERABLE BLOWING AND DRIFTING SNOW. SNOWFALL OF 1 TO 2 FEET IN THE FAR WEST MOUNTAINS WITH 6 TO 12 INCHES IN THE VALLEYS IS POSSIBLE BY FRIDAY EVENING. STAY TUNED TO THE LATEST FORECAST ON THIS POTENTIAL SIGNIFICANT WINTER STORM. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ASKED TO REPORT STRONG WIND IN EXCESS OF 40 MPH TODAY AND TONIGHT. THANK YOU. TEAM RIVERTON
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 1207 PM MST WED DEC 31 2008 WYZ003-010100- CODY FOOTHILLS- 1207 PM MST WED DEC 31 2008 ...POCKETS OF STRONG WIND GUSTS REMAIN ACROSS THE CODY FOOTHILLS THIS AFTERNOON... LOCAL AREAS OF GUSTY WINDS OF 20 TO 30 MPH WITH OCCASIONAL GUSTS TO 50 MPH WILL BE ENCOUNTERED IN THE CODY AREA AND SURROUNDING FOOTHILLS...INCLUDING HIGHWAY 120 THROUGH 6 PM. TRAVELERS SHOULD EXPECT TO ENCOUNTER SUDDEN STRONG CROSSWIND IN THESE AREAS THIS AFTERNOON AND EVENING AS WELL AS DEBRIS BLOWING ACROSS THE ROAD. DSB
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 1214 PM MST WED DEC 31 2008 WYZ003-312200- CODY FOOTHILLS- 1214 PM MST WED DEC 31 2008 ...POCKETS OF STRONG WIND GUSTS REMAIN ACROSS THE CODY FOOTHILLS THIS AFTERNOON... LOCAL AREAS OF GUSTY WINDS OF 20 TO 30 MPH WITH OCCASIONAL GUSTS TO 50 MPH WILL BE ENCOUNTERED IN THE CODY AREA AND SURROUNDING FOOTHILLS...INCLUDING HIGHWAY 120 THROUGH 3 PM. TRAVELERS SHOULD EXPECT TO ENCOUNTER SUDDEN STRONG CROSSWIND IN THESE AREAS THIS AFTERNOON AS WELL AS DEBRIS BLOWING ACROSS THE ROAD. DSB
The national radar mosaic for the moment the first event began.
1 high wind. Local standard time, as filed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2008Every state in 2008This day in weather historyWarnings in Wyoming, December 2008
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 142161.