A strong cold front pushed south into Wyoming during the morning hours of Wednesday, November 18. The pressure gradient and favorable winds aloft combined to produce widespread high winds over most lower elevation locations.
Every event with a place to put it; 10 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS RIW wrote it up.
A strong cold front pushed south into Wyoming during the morning hours of Wednesday, November 18. The pressure gradient and favorable winds aloft combined to produce widespread high winds over most lower elevation locations. Ahead of the front, westerly wind routinely gusted between 60 and 70 mph, especially during the morning and midday hours. Peak winds across northern Wyoming were generally from the northwest and occurred immediately after passage of the cold front. Some of the strongest winds were recorded in northern Johnson County, where peak speeds of 74 mph and 84 mph were observed at the Buffalo airport and a mesonet sensor along I-90 east of Buffalo, respectively. The strongest gusts were registered west of Clark during the early morning with the peak gust being 104 mph around 0100MST.
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 17, 2:34 PM MST, 5 hours 34 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RIVERTON WY 234 PM MST TUE NOV 17 2015 .SHORT TERM...TONIGHT THROUGH FRIDAY COLD SHORTWAVE FAST APPROACHING FROM THE NW AND THIS SYSTEM WILL RESULT IN A LOT OF WIND...SOME OF IT HIGH TO DAMAGING...AND AREAS OF SNOW. A PLETHORA OF HIGHLIGHTS WILL BE GOING OUT WITH THE AFTERNOON PACKAGE WITH HIGH WIND WATCHES AND WARNINGS COVERING A SIGNIFICANT CHUNK OF THE CENTRAL AND SOUTHWEST WILL BE COVERED BY THESE HIGHLIGHTS WITH A FEW SPS WHERE NO HIGH WIND PRODUCTS WILL BE OUT. IN THE WEST...DEVELOPING UPGLIDE WILL BE REPLACED BY DYNAMICS FROM APPROACHING SHORTWAVE RESULTING IN SOME LIGHT SNOW THIS EVENING WHICH WILL THEN INTENSIFY OVERNIGHT WITH APPROACHING COLD FRONT AS WILL THE WIND. DUE TO THE COMBINATION OF THE SNOW AND WIND...WE WILL ISSUE A WINTER WEATHER ADVISORY FOR THE JACKSON AND STAR VALLEYS AND TETON/GROS VENTRE ZONE. THE TETONS...NRN STAR VALLEY AND NRN JACKSON VALLEY WILL LIKELY DO BEST IN THE NW FLOW. SOUTH WIND WILL SHIFT MORE TO THE WEST OR NW WITH FROPA WED MORNING OUT THERE AT SPEEDS OF 2O TO 35 MPH WITH GUSTS OVER 40 MPH IN OPEN AREAS CAUSING BLOWING AND DRIFTING SNOW. THE MOUNTAINS WILL SEE STRONGER WINDS YET. NOW BACK TO THE WIND...HIGH WIND EVENT FOR THE CODY FOOTHILLS AND ABSAROKAS IS STILL LOOKING QUITE STRONG. NO REAL CHANGE FROM YESTERDAY WITH STRONG MTN WAVE ACTION POSSIBLE PER WRF CROSS-SECTION WITH PEAK PERIOD BEING THE TRADITIONAL LATE NIGHT PERIOD. UPSTREAM SOUNDINGS ARE STILL SHOWING A NEAR MTN TOP INVERSION. ALREADY SEEING SOME BRIEF HIGH WIND ON THE HIGHWAY SENSOR 8S OF CLARK. MAY NEED TO BUMP BACK THE TIMING TO START A FEW HOURS EARLY INSTEAD OF 5 PM. OTHERWISE...EVERYTHING ON TRACK. THEN WE HAVE TO DEAL WITH WEDNESDAY'S HIGH WIND AS VERY STRONG PRESSURE GRADIENT COMBINES WITH VERY STRONG FLOW ALOFT AS NOSE OF 150KT JET MOVES INTO THE AREA AND FRONTAL BOUNDARY SAGS SOUTH INTO OUR NRN AND ERN ZONES. THIS FRONT WILL ACTUALLY HELP SHUT OFF THE HIGH WINDS FOR THE CODY FOOTHILLS BUT MAY INITIATE THE HIGH WINDS FOR THE NRN BIGHORN BASIN OVER TO NRN JOHNSON COUNTY. THE ABSAROKAS WILL HAVE TO BE WATCHED AS HIGH WINDS COULD CONTINUE PAST 15Z WITH IMPRESSIVE NW FLOW. ALSO...THE FAVORED NW FLOW DUBOIS AREA WILL LIKELY BLOW HIGH WIND AT TIMES TONIGHT AND WEDNESDAY AND WILL ISSUE A HIGH WIND WARNING THERE AS WINDS ARE ALREADY GUSTING OVER 40 TO 45 AT THE AIRPORT AND CROWHEART AND OVER 30 MPH AT TIMES IN TOWN. THIS HIGH WIND MAY MAKE IT DOWN TO RIVERTON AFTER 16Z WED AND PEAK IN THE AFTERNOON BEFORE DECREASING AFTER 5 PM. THE I80 CORRIDOR WILL ALSO BE BLOWING VERY STRONG AND A HIGH WIND WATCH WILL BE OUT FOR THERE ON WEDNESDAY ALONG WITH THE UPPER GREEN FOR FAVORED NW FLOW. BESIDES THE SNOW OUT WEST...WE WILL LIKELY SEE SOME AREAS OF LIGHT SNOW OR FLURRIES BEHIND OUR FRONTAL BOUNDARY IN THE NORTH AND EAST. NOT MUCH ACROSS THE LOWER ELEVATIONS BUT WITH THE COLDER TEMPS AND WIND...ANY SNOW WILL BE BLOWN AROUND AND MAKE IT FEEL JUST A LITTLE WINTRY. WINDY AREAS WILL CONTINUE WEDNESDAY NIGHT AS WE AWAIT THE NEXT SYSTEM TO IMPACT THE AREA THURSDAY THROUGH FRIDAY. ISENTROPIC UPGLIDE WILL RETURN TO THE WEST WEDNESDAY NIGHT AND INCREASE THROUGH THE DAY THURSDAY. NEXT COLD FRONT PUSHES S AND SE ACROSS THE AREA THURSDAY NIGHT AND FRIDAY WITH SHARPLY COLDER AIR AND PERIODS OF CONTINUED SNOW AND WIND OUT WEST WITH AREAS OF LIGHT SNOW DEVELOPING EAST OF THE DIVIDE. LOWERED TEMPS FURTHER FRIDAY BUT THEY MAY NEED A LITTLE MORE NUDGING DOWN YET. THE WEST MAY SEE A SIGNIFICANT IMPACT FROM SNOW...WIND AND FALLING TEMPS WITH THIS SYSTEM BETTER UPPER SUPPORT WITH THIS SYSTEM. LATER SHIFTS CAN DEAL WITH POTENTIAL WATCHES AND ADVISORIES TOMORROW FOR THE WEST. .LONG TERM...FRIDAY NIGHT THROUGH TUESDAY OVERALL...WITH NRN HEMISPHERE PATTERN CURRENTLY IN TRANSITION FROM 4/5 WAVE TO 3 WAVE PATTERN...MR/LR MDL SOLUTIONS CONTINUE TO SHOW SOLUTION DIVERGENCE AT THE BEGINNING OF THE FCST PERIOD. HOWEVER...LUCKILY...MOST OF THE DIFFERENCES DO NOT AFFECT THE OUTCOME OF THE SENSIBLE WX WITH TWO RATHER MINOR EXCEPTIONS. ONE...GFS CONTINUES TO SHOW...FOR FOUR RUNS NOW...OPEN EJECTING MINOR SW TROF LATE SAT TO SUN AM OVR THE SRN FA...WITH VERY LOW END CHCS FOR LIGHT SNOW DURING THIS TIME PERIOD. TWO...WHILE UPR NW FLOW IS CLEAR IN ALL MDLS AT LEAST UNTIL MONDAY...THE EURO APPEARS DOES SLIGHTLY WARMER THAN THE GFS WITH THE CAN WOBBLING BETWEEN THOSE TWO. GOING WITH THE SLIGHT CHCS ACROSS THE SRN FA SAT NIGHT/SUN MORNING IN RESPONSE TO THE AFOREMENTIONED SW...AND ERRING SOMEWHAT ON THE COOL SIDE...ESPECIALLY AT NIGHT AND W OF THE DIVIDE. MDLS THEN START TO CONVERGE ONCE AGAIN ON MONDAY AS TRANSITION TO UPR SW FLOW TAKES PLACE OVR THE FA AS A COUPLE OF LARGE TROFS MOVE DOWN OVR THE WRN CONUS. BY THIS TIME...TIMING DIFFERENCES IN THE MDLS WITH RESPECT TO THE UPR FLOW PATTERN/TRAJECTORY ACTUALLY HELP IN OVERCOMING DIFFERENCES IN THE TIMING OF THE DYNAMICS OF THE SYSTEM(S)...AT LEAST AS FAR AS THE ONSET OF PRECIP OUT WEST IS CONCERNED LATE TUESDAY. BEYOND THIS FCST PERIOD AND THRU THANKSGIVING...THE GFS...BEING MUCH QUICKER IN OVERALL EVOLUTION OF THE SYSTEM...OPENS AND MOVES THRU THE REGION WED AND THU...WHILE THE EURO LAGS WELL BEHIND DEVELOPING OVR THE GREAT BASIN AND NOT REALLY MOVING ONWARD UNTIL LATER FRIDAY/OVR THE WEEKEND...KEEPING THE FA IN THE MUCK THROUGHOUT. && .AVIATION.../00Z ISSUANCE/ EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES VFR CONDITIONS WILL PREVAIL ACROSS THE REGION AND FOR MOST TERMINAL LOCATIONS THROUGH THE FORECAST PERIOD. A POSSIBLE BRIEF EXCEPTION TO THIS RULE WILL BE AT/NEAR KCPR AROUND MID-DAY WITH POSSIBLE MVFR CONDITIONS IN LOWER CIGS POSSIBLE WITH A FRONTAL PASSAGE. OTHERWISE...THE WIND WILL REMAIN QUITE GUSTY AROUND KCOD AND OVER THE ABSAROKA MOUNTAINS AFTER THROUGH THE FORECAST PERIOD...WITH WIND SPEEDS INCREASING DRAMATICALLY OVER/NEAR THE OTHER TERMINAL SITES AFTER 13Z...WITH HIGH WIND GUSTS GREATER THAN 50 KTS POSSIBLE AT TIMES. AREAS WITH POTENTIAL MOUNTAIN WAVE ACTIVITY AND TURBULENCE...INCLUDING LLWS...WILL ALSO INCREASE AFTER 06Z. PLEASE SEE INDIVIDUAL TERMINAL FORECASTS FOR MORE DETAILS. WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES VFR CONDITIONS WILL PREVAIL AT KBPI AND KRKS TERMINAL SITES THROUGH THE PERIOD...AND AT KJAC AND KPNA THROUGH 01Z AND 07Z. THEN...KJAC AND KPNA WILL SEE MVFR CONDITIONS INCREASING IN LOW CIGS...WITH -SN AND REDUCED VIS ALSO POSSIBLE AT KJAC AFTER 06Z. THE MOUNTAINS OF WESTERN WY WILL ALSO SEE SNOW SHOWERS AND MVFR TO OCCASIONAL IFR CONDITIONS IN REDUCED VIS AND LOWER CIGS DEVELOPING THIS EVENING...LASTING TO AROUND 18Z. ADDITIONALLY...VERY WINDY CONDITIONS WILL OCCUR AT/NEAR ALL TERMINALS AFTER 11Z...WITH HIGH WIND GUSTS GREATER THAN 50 KTS POSSIBLE AFTER 16Z. AREAS WITH POTENTIAL MOUNTAIN WAVE ACTIVITY AND TURBULENCE...INCLUDING LLWS...WILL ALSO INCREASE AFTER 06Z. PLEASE SEE INDIVIDUAL TERMINAL FORECASTS FOR MORE DETAILS. && .FIRE WEATHER... THE MAIN WEATHER CONCERN THROUGH WEDNESDAY WILL BE WIND. MANY AREAS WILL SEE STRONG WIND DEVELOPING...ESPECIALLY TONIGHT INTO WEDNESDAY. MANY AREAS IN THE CENTRAL AND SOUTHWEST WILL SEE STRONG IF NOT HIGH WIND ON WEDNESDAY. SNOW WILL ALSO FALL AT TIMES WEST OF THE DIVIDE TONIGHT INTO WEDNESDAY AND THEN AGAIN THURSDAY AND FRIDAY. A COLD FRONT MAY ALSO BRING A LITTLE SNOW ACROSS THE NORTH AND EAST WEDNESDAY WITH STRONG NORTH WIND. && .RIW WATCHES/WARNINGS/ADVISORIES... HIGH WIND WATCH FROM LATE TONIGHT THROUGH WEDNESDAY AFTERNOON FOR WYZ004-010-028>030. HIGH WIND WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY AFTERNOON FOR WYZ017-025-026. WINTER WEATHER ADVISORY UNTIL 11 AM MST WEDNESDAY FOR WYZ012-013- 023. HIGH WIND WATCH THROUGH WEDNESDAY AFTERNOON FOR WYZ016. HIGH WIND WARNING UNTIL 8 AM MST WEDNESDAY FOR WYZ002. HIGH WIND WARNING UNTIL 8 AM MST WEDNESDAY FOR WYZ003. && SHORT TERM...SKRBAC LONG TERM...BRAUN AVIATION...BRAUN FIRE WEATHER...SKRBAC
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RIVERTON WY 200 PM MST TUE NOV 17 2015 WYZ001>020-022>030-181300- YELLOWSTONE NATIONAL PARK-ABSAROKA MOUNTAINS-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- TETON AND GROS VENTRE MOUNTAINS-JACKSON HOLE- WIND RIVER MOUNTAINS WEST-WIND RIVER MOUNTAINS EAST- UPPER WIND RIVER BASIN-WIND RIVER BASIN-LANDER FOOTHILLS- GREEN MOUNTAINS AND RATTLESNAKE RANGE- NATRONA COUNTY LOWER ELEVATIONS-CASPER MOUNTAIN-STAR VALLEY- SALT RIVER AND WYOMING RANGES-UPPER GREEN RIVER BASIN FOOTHILLS- UPPER GREEN RIVER BASIN-SOUTH LINCOLN COUNTY- ROCK SPRINGS AND GREEN RIVER-FLAMING GORGE-EAST SWEETWATER COUNTY- 200 PM MST TUE NOV 17 2015 ...WINTER WEATHER ADVISORY FOR PORTIONS OF FAR WEST WYOMING FOR TONIGHT AND WEDNESDAY MORNING... ...HIGH WIND WARNING FOR THE CODY FOOTHILLS THIS AFTERNOON THROUGH WEDNESDAY MORNING AND FOR THE ABSOROKA MOUNTAINS TONIGHT THROUGH WEDNESDAY MORNING... ...HIGH WIND WATCH FOR PORTIONS OF WESTERN AND CENTRAL WYOMING FOR WEDNESDAY... THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF WY...CENTRAL WYOMING...NORTH CENTRAL WYOMING...NORTHWEST WYOMING...SOUTH CENTRAL WYOMING...SOUTHWEST WYOMING AND WEST CENTRAL WYOMING. .DAY ONE...THIS AFTERNOON AND TONIGHT SIGNIFICANT SNOWFALL EXPECTED OVER THE FAR WESTERN VALLEYS AS WELL AS OVER THE TETONS AND GROS VENTRE RANGE TONIGHT. SEE WINTER WEATHER ADVISORIES FOR MORE INFORMATION. STRONG TO VERY STRONG DAMAGING WEST TO NORTHWEST WINDS ARE EXPECTED THIS AFTERNOON THROUGH TONIGHT IN THE CODY FOOTHILLS AND THE ADJACENT ABSAROKA MOUNTAINS. SEE HIGH WIND WARNING FOR MORE INFORMATION. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY WEDNESDAY...SIGNIFICANT SNOWFALL EXPECTED OVER THE FAR WESTERN VALLEYS AS WELL AS OVER THE TETONS AND GROS VENTRE RANGE WEDNESDAY MORNING. STRONG TO VERY STRONG DAMAGING WINDS ARE EXPECTED ACROSS THE CODY FOOTHILLS AND ADJACENT ABSAROKA MOUNTAINS WEDNESDAY MORNING. STRONG TO VERY STRONG DAMAGING WINDS ARE POSSIBLE ACROSS OTHER PORTIONS OF WESTERN AND CENTRAL WYOMING WEDNESDAY. FRIDAY...AREAS OF LIGHT SNOW AND BLOWING SNOW POSSIBLE ACROSS NORTH AND CENTRAL WYOMING. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ENCOURAGED TO REPORT SNOWFALL AMOUNTS OR WIND GUSTS GREATER THAN 50 MPH. THANK YOU.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 304 PM MST TUE NOV 17 2015 WYZ014-015-181200- WIND RIVER MOUNTAINS WEST-WIND RIVER MOUNTAINS EAST- 304 PM MST TUE NOV 17 2015 WEST WINDS WILL BE ON THE INCREASE OVER THE WIND RIVER MOUNTAINS TONIGHT...CONTINUING THROUGH WEDNESDAY. WEST WINDS WILL INCREASE TO 30 TO 40 MPH TONIGHT WITH GUSTS OF 50 TO 60 MPH. TRAVEL OVER SOUTH PASS WILL BE HAMPERED BY THESE VERY STRONG CROSS WINDS AT TIMES. CHECK THE LATEST ROAD CONDITIONS AT WYOROAD.INFO OR BY DIALING 5 1 1 BEFORE VENTURING OUT. WYZ009-181200- BIGHORN MOUNTAINS SOUTHEAST- 304 PM MST TUE NOV 17 2015 WEST WINDS WILL BE ON THE INCREASE OVER THE BIG HORN MOUNTAINS TONIGHT...CONTINUING THROUGH WEDNESDAY. WEST WINDS WILL INCREASE TO 30 TO 40 MPH TONIGHT WITH GUSTS OF 50 TO 60 MPH. TRAVEL OVER WILL BE HAMPERED BY THESE VERY STRONG CROSS WINDS AT TIMES. CHECK THE LATEST ROAD CONDITIONS AT WYOROAD.INFO OR BY DIALING 5 1 1 BEFORE VENTURING OUT. WYZ007-181200- OWL CREEK AND BRIDGER MOUNTAINS- 304 PM MST TUE NOV 17 2015 A STRONG COLD FRONT WILL PUSH SOUTHEAST ACROSS THE AREA ON WEDNESDAY WITH VERY STRONG NORTHWEST WIND AND SCATTERED SNOW SHOWERS. THE NORTHWEST WIND WILL BLOW 25 TO 35 MPH WITH GUSTS OVER 50 MPH ON WEDNESDAY. WYZ011-181200- SOUTHEAST JOHNSON COUNTY- INCLUDING THE CITY OF...KAYCEE 304 PM MST TUE NOV 17 2015 A STRONG COLD FRONT WILL PUSH SOUTH ACROSS THE AREA ON WEDNESDAY WITH VERY STRONG NORTH WIND AND SCATTERED SNOW SHOWERS. THE NORTH WIND WILL BLOW 25 TO 35 MPH WITH GUSTS OVER 50 MPH ON WEDNESDAY. WYZ001-181200- YELLOWSTONE NATIONAL PARK- INCLUDING THE CITIES OF...LAKE...MAMMOTH...OLD FAITHFUL 304 PM MST TUE NOV 17 2015 A QUICK HITTING STORM SYSTEM WILL IMPACT THE PARK TONIGHT THROUGH WEDNESDAY MORNING WITH SNOW AND INCREASING WIND. LIGHT SNOW WILL BECOME WIDESPREAD THIS EVENING AND INCREASE FOR A FEW HOURS LATE TONIGHT AND WEDNESDAY MORNING ALONG WITH STRONG WIND. SNOWFALL AMOUNTS OF 3 TO 6 INCHES ARE EXPECTED IN THE MOUNTAINS WITH 1 TO 3 INCHES ACROSS THE LOWER ELEVATIONS. SOUTH WIND OF 15 TO 25 MPH WILL DEVELOP TONIGHT AND THEN INCREASE AND SHIFT TO THE WEST WEDNESDAY MORNING AT SPEEDS OF 20 TO 30 MPH WITH GUSTS AROUND 40 MPH. BE PREPARED FOR THE QUICK CHANGE BACK TO WINTRY WEATHER TONIGHT AND WEDNESDAY MORNING. ANOTHER ROUND OF SNOW IS EXPECTED ON THURSDAY. SKRBAC
The national radar mosaic for the moment the first event began.
10 high wind. Local standard time, as filed.
Very strong wind gusts occurred in the favored areas near Clark. There were many gusts of hurricane force recorded including a maximum of 104 mph around 0100MST.
The weather sensor on Outer Drive in Casper reported several wind gusts above 58 mph including a maximum of 68 mph around 0350MST.
Thr RAWS site at Camp Creek recorded several hours of wind gusts over 58 mph including a maximum of 81 mph. The site at Fales Rock had a maximum gust of 68 mph.
Several sites across northern Johnson County recorded wind gusts over 58 mph. Some of the strongest gusts included 84 mph at Indian Creek and 74 mph at the Buffalo Airport.
A wind gust of 60 mph was recorded at North Big Horn County Airport in Cowley. The ASOS at the South Big Horn County Airport in Greybull registered a wind gust of 58 mph.
Wind gusts over 58 mph were recorded at numerous sites across eastern Sweetwater County. The maximum gust was 68 mph at Rock Springs-Sweetwater County Airport at 1127MST.
A wind gust of 59 mph was recorded at the Dubois Airport with a peak gust of 58 mph at Crowheart.
The WYDOT sensor at Farson had sustained wind up to 43 mph.
The ASOS at Riverton Regional Airport recorded a wind gust of 60 mph. A wind gust of 62 mph was recorded northwest of Hudson at the Sharpnose RAWS.
A WYDOT wind sensor on the west side of Rock Springs recorded a wind gust of 65 mph. The sensor at Peru Hill along Interstate 80 had a gust of 59 mph.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2015Every state in 2015This day in weather historyWarnings in Wyoming, November 2015
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: 606352, 606488, 606490, 606356, 606489, 606355, 606353, 609814, 606358, 606354.