Strong wind of over 100 mph was measured west of Clark. The extreme speeds were caused by gap flow and mountain wave activity.
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The episode as NWS RIW wrote it up.
Strong wind of over 100 mph was measured west of Clark. The extreme speeds were caused by gap flow and mountain wave activity. High wind also impacted Lander and the surrounding foothills along with the central wind corridor in Natrona and southeast Fremont counties. The Lander ASOS measured a gust to 59 mph. Gusts over 70 mph were recorded at an automated station in the Rattlesnake Range.
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 Nov 16, 3:32 PM MST, 5 hours 58 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RIVERTON WY 332 PM MST WED NOV 16 2011 .SHORT TERM...TONIGHT THROUGH SATURDAY VERY ACTIVE AND QUICKLY CHANGING WEATHER WILL DOMINATE THE SHORT TERM. MODELS CONTINUE TO SHOW THE POTENTIAL FOR A CLASSIC HIGH WIND EVENT FOR THE CODY FOOTHILLS TONIGHT THROUGH THURSDAY. THE FIRST PART TONIGHT WILL BE A MIXTURE OF GAP FLOW...WITH IMPRESSIVE 15C H7 THERMAL GRADIENT FORECAST BY THE WRF...AND MOUNTAIN WAVE. THE WRF AND NAM12 CONTINUE TO INDICATE A STRONG MOUNTAIN TOP INVERSION DEVELOPING THIS EVENING AND HOLDING INTO THURSDAY MORNING AS FLOW INCREASES FROM 30 TO 40KTS. MOUNTAIN WAVE STUDIES SHOW THAT THAT WIND CAN BE MULTIPLIED BY 2.86 WHEN MOUNTAIN WAVES BREAK. 30KTS CAN RESULT IN 85KTS ON THE LEE SLOPE WHILE 40KTS COULD RESULT IN 114KTS TO THE LEE OF THE MOUNTAIN BARRIER. THERMAL GRADIENT AND INCREASING FLOW SUGGESTS VERY STRONG GAP FLOW SOUTH OF CODY LATER TONIGHT AND IN THE CLARK'S FORK GAP ALL NIGHT INTO THURSDAY. THE STRONGEST MOUNTAIN WAVE SIGNATURE IS IN THE CLASSIC TIMEFRAME OF 09-12Z BUT SIGNATURE SUGGESTS THAT ANYTIME FROM ABOUT 03Z ONWARD THE POTENTIAL IS THERE. THE ARW4 EAST IS SHOWING A BREAKING WAVE TOWARDS SUNRISE THURSDAY. ON THURSDAY...THE NOSE OF A STRONG 100KT+ JET MOVES JUST TO OUR NORTH PROVIDING POTENTIAL FOR STRONG SINKING MOTION...CONVERGENCE FOR ADDED DOWNSLOPE WIND POTENTIAL DURING THE DAY THURSDAY. SHOULD BE A VERY INTERESTING 24 HOURS. FURTHER SOUTH IN THE WIND CORRIDOR...THE MID LEVEL FLOW BEGINS TO BACK ON THURSDAY AS LEE SIDE LOW DEVELOPS IN FAR NERN WYO THURSDAY AFTERNOON. WRF IS SHOWING A GOOD AREA OF 50-55KT AT H7 ACROSS THE WIND CORRIDOR BY 15Z. ALREADY UPGRADED THE WATCH TO A WARNING FOR THE GREEN MTNS...RATTLESNAKE RANGE AND IT'S QUITE LIKELY THE CASPER ZONE WILL NEED TO BE UPGRADED LATER TONIGHT. ALSO CONCERNED ABOUT THE POTENTIAL FOR THE LANDER FOOTHILLS TOMORROW NIGHT AS THE FLOW BECOMES MORE SOUTHWEST OVER THE WINDS AND THE RIGHT FRONT QUAD OF THE JET GETS CLOSE ENOUGH TO PROVIDE DOWNWARD MOTION. ISSUED A HIGH WIND WATCH FOR THIS AREA FROM 00Z-12Z FRIDAY. OUT WEST...THE ISSUE WILL BE SNOW COMBINED WITH WIND. THE BEST AREA I SEE AS OF NOW FOR AT LEAST THE POTENTIAL FOR WIDESPREAD 12"+ AMOUNTS IS IN THE TETONS ZONE. HAVE ISSUED A WATCH THERE FOR THURSDAY THROUGH FRIDAY. ISENTROPIC UPGLIDE RETURNS QUICKLY THURSDAY MORNING AND INTENSIFIES INTO THE EVENING HOURS BEFORE TROUGH DYNAMICS...QG...JET STREAK TAKE OVER THURSDAY NIGHT AND FRIDAY. TOUGH CALL FOR THE JACKSON VALLEY AND STAR VALLEY. A LOT WILL DEPEND ON HOW THE SNOW AND MILDER MID LEVEL TEMPERATURES INTERACT IN THIS AREA DURING THE DAY THURSDAY. IT'S STILL POSSIBLE THAT A WATCH MAY BE NEEDED FOR THESE AREAS. OTHERWISE...MUCH OF THE WEST WILL NEED WINTER WEATHER ADVISORIES FOR THIS PERIOD. THE FRONT WILL THEN DROP SOUTH EAST OF THE DIVIDE LATER THURSDAY NIGHT INTO FRIDAY MORNING WITH SNOW QUICKLY DEVELOPING. GFS AND ECMWF FASTER WITH THE OVERRUNNING INTO CENTRAL WYOMING AND THUS SPED UP THE TIMING 6 HOURS. STILL UNCERTAINTY ON THE AMOUNTS EAST OF THE DIVIDE BUT WE'LL LIKELY NEED SOME ADVISORIES...EAST IN THE CENTRAL TO NE ZONES. COULD ALSO SEE A MID LEVEL CIRCULATION COME INTO PLAY ACROSS THE WIND RIVER BASIN FRIDAY NIGHT INTO EARLY SATURDAY. TEMPERATURES WILL BE TRICKY TONIGHT WITH RAPID RETURN TO SOUTHWEST FLOW AND WARMING MID LEVEL TEMPERATURES. A LOT OF AREAS EAST OF THE DIVIDE NEAR THE FOOTHILLS AND IN THE WIND CORRIDOR WILL LIKELY SEE THEIR LOWS THIS EVENING WITH WARMING TEMPERATURES LATER TONIGHT. MUCH MILDER THURSDAY AND WINDY...THEN SHARPLY COLDER AGAIN FRIDAY WITH SNOW DEVELOPING. .LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY MODELS BEGIN THE MID RANGE IN DECENT AGREEMENT WITH THE PLACEMENT AND MOVEMENT OF LARGE SCALE FEATURES...SO A GFS EC BLEND WAS USED THROUGH THE WEEKEND. THE GFS THEN BEGINS TO DIVERGE FROM OTHER MODEL SOLUTIONS LATER IN THE PERIOD SO MORE WEIGHT WAS PLACED UPON THE EUROPEAN FOR TIMING AND STRENGTH OF FEATURES LATER IN THE PERIOD. A STORM SYSTEM MOVES INTO THE PLAINS ON SATURDAY NIGHT...LEAVING BEHIND SOME LIGHT SNOW ACROSS CENTRAL AND NORTHERN PORTIONS OF THE STATE. SOME VERY COLD AIR WILL REMAIN BEHIND AS WELL...LOWERED TEMPERATURES IN CALM BASINS ON SATURDAY NIGHT INTO SUNDAY MORNING AS A RESULT. DRY AND SLIGHTLY MILDER TEMPERATURES PREVAIL ACROSS MOST OF THE NORTH SUNDAY WITH LINGERING SNOW SHOWERS ACROSS THE SOUTH AND WEST. A SIGNIFICANT WARMING TREND FOLLOWS MONDAY THROUGH WEDNESDAY WITH MAINLY DRY WEATHER AS A RIDGE BUILDS IN. THE MODELS ARE HINTING AT A LEE TROUGH POSSIBLY FORMING ON WEDNESDAY...WHICH COULD INCREASE WINDS ACROSS THE MOUNTAINS AND LEE SIDE FOOTHILLS. THE MODELS KEEP THIS BASIC SET UP THROUGH AT LEAST THANKSGIVING DAY...HAVE FORCED TEMPERATURES UP A FEW DEGREES ACROSS THE CODY AND LANDER FOOTHILLS TO COVER THIS POSSIBILITY. .AVIATION.../00Z ISSUANCE/ VERY TURBULENT AND WINDY CONDITIONS ARE EXPECTED TO DEVELOP OVER THE MOUNTAINS...WITH A DEVELOPING MOUNTAIN WAVE CAUSING VERY STRONG WINDS OVER THE ABSAROKA AND ADJACENT CODY FOOTHILLS TONIGHT...AND POSSIBLY DEVELOPING IN THE LANDER AREA A LITTLE LATER. HAVE KEPT WINDS RELATIVELY LIGHT AT KCOD AND KLND TONIGHT...WITH THE STRONGEST WINDS STAYING ALOFT AND COMING FROM A SLIGHTLY MORE WESTERLY DIRECTION ABOVE KCOD....THUS WILL HAVE SOME LOW LEVEL WIND SHEAR IN THE COD AND LND TAFS. ANOTHER POSSIBLY WINDY AREA WILL BE ALONG THE OWL CREEKS WITH A POSSIBLE WAVE DEVELOPING...PUSHING SOME GUSTY WINDS INTO KWRL AFTER 15Z THURSDAY ...THOUGH GUSTS WILL BE MUCH LIGHTER THAN THOSE EXPECTED AT KCOD AND KLND. HIGH WINDS ARE ALSO EXPECTED THROUGH THE WIND CORRIDOR AFTER 15Z THURSDAY...MAINLY FROM JEFFREY CITY TO KCPR. LIGHT SNOW IS ALSO EXPECTED TO BREAKOUT ACROSS THE NORTHWEST WITH SOME MVFR/IFR CONDITIONS DEVELOPING TOWARD MORNING...WHICH COULD AFFECT KJAC TERMINAL...MAINLY AFTER 16Z THURSDAY. SOME STRONGER SOUTHWESTERLY WINDS COULD ALSO MIX DOWN INTO THE JACKSON VALLEY...CAUSING VISIBILITY REDUCTIONS IN SNOW AND BLOWING SNOW TOMORROW. SNOW WILL SPREAD ACROSS THE NORTH THROUGH 06Z FRI AND THEN BEGIN TO SPREAD SOUTH. .FIRE WEATHER... WEST TO SOUTHWEST WINDS WILL REDEVELOP AND INCREASE ACROSS MUCH OF THE AREA TONIGHT INTO THURSDAY NIGHT. THESE STRONG WINDS WILL FIRST SURFACE IN THE CODY FOOTHILLS TONIGHT AND THURSDAY AND THEN DEVELOP FROM JEFFREY CITY TO CASPER LATER TONIGHT THROUGH THURSDAY. STRONG MOUNTAIN TOP WINDS WILL ALSO DEVELOP LATER TONIGHT THROUGH THURSDAY. VERY STRONG WINDS MAY ALSO DEVELOP IN THE LANDER FOOTHILLS THURSDAY NIGHT. SNOW WILL RETURN TO THE WEST THURSDAY AND CONTINUE THROUGH FRIDAY. SNOW WILL THEN SPREAD SOUTH ACROSS AREAS EAST OF THE DIVIDE ON FRIDAY AND CONTINUE INTO SATURDAY. && .RIW WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING FROM 8 PM THIS EVENING TO 5 PM MST THURSDAY WYZ002-003. HIGH WIND WARNING FROM 2 AM TO 5 PM MST THURSDAY WYZ019. HIGH WIND WATCH FROM THURSDAY AFTERNOON THROUGH LATE THURSDAY NIGHT WYZ018. HIGH WIND WATCH FROM LATE TONIGHT THROUGH THURSDAY AFTERNOON WYZ020. WINTER STORM WATCH FROM LATE TONIGHT THROUGH FRIDAY AFTERNOON WYZ012. && SHORT TERM...SKRBAC LONG TERM...ALLEN AVIATION...ALLEN FIRE WEATHER...SKRBAC
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RIVERTON WY 300 PM MST WED NOV 16 2011 WYZ001>020-022>030-171200- 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- 300 PM MST WED NOV 16 2011 ...HIGH WIND WARNING FOR THE CODY FOOTHILLS...ABSAROKA MOUNTAINS TONIGHT AND THURSDAY... ...HIGH WIND WARNING FOR THE GREEN/RATTLESNAKE MOUNTAINS LATE TONIGHT THROUGH THURSDAY... ...HIGH WIND WATCH FOR NATRONA COUNTY THURSDAY... ...HIGH WIND WATCH LANDER FOOTHILLS THURSDAY NIGHT... ...WINTER STORM WATCH TETON AND GROS VENTRE RANGES THURSDAY THROUGH FRIDAY... THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING. .DAY ONE...TODAY AND TONIGHT STRONG WINDS WILL DEVELOP ACROSS THE CODY FOOTHILLS AND ABSAROKA MOUNTAINS THIS EVENING. STRONG WINDS WILL ALSO DEVELOP LATER TONIGHT ACROSS THE GREEN AND RATTLESNAKE MOUNTAINS. PLEASE SEE HIGH WIND WATCH PRODUCT FOR THE LATEST INFORMATION. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY THURSDAY...STRONG WINDS ARE EXPECTED TO CONTINUE ACROSS THE AREAS IN THE HIGH WIND WARNING THROUGH THURSDAY AFTERNOON. HIGH WINDS MAY ALSO DEVELOP ACROSS NATRONA COUNTY DURING THE MORNING. SNOWFALL...WITH AREAS OF BLOWING AND DRIFTING SNOW AND LIMITED VISIBILITY...WILL DEVELOP ACROSS THE WESTERN MOUNTAINS AND FAR WEST VALLEYS. SNOW MAY BECOME HEAVY AT TIMES IN THE TETONS. FRIDAY AND SATURDAY...SNOW...POSSIBLY HEAVY AT TIMES... CONTINUING IN THE WEST AND DEVELOPING IN THE NORTH FRIDAY...SPREADING SOUTH AND EAST THROUGH FRIDAY NIGHT INTO SATURDAY MORNING. BITTERLY COLD WIND CHILL TEMPERATURES...WITH AREAS OF BLOWING AND DRIFTING SNOW AND LIMITED VISIBILITY FRIDAY NIGHT AND SATURDAY. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ENCOURAGED TO REPORT WIND GUSTS OVER 50 MPH. THANK YOU. TEAM RIVERTON
The national radar mosaic for the moment the first event began.
5 high wind. Local standard time, as filed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2011Every state in 2011This day in weather historyWarnings in Wyoming, November 2011
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: 354587, 354588, 354590, 354591, 354589.