Strong winds in the mid levels of the atmosphere combined with a strong pressure difference at the surface produced strong winds for several hours.
Every event with a place to put it; 1 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 CYS wrote it up.
Strong winds in the mid levels of the atmosphere combined with a strong pressure difference at the surface produced strong winds for several hours.
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 Cheyenne, WY wrote its last area forecast discussion before the first event at Oct 12, 9:52 PM MST, 4 hours 33 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHEYENNE WY 1052 PM MDT WED OCT 12 2011 .AVIATION...06Z TAFS VFR CONDITIONS EXPECTED NEXT 24 HOURS. STRONG WEST TO NORTHWEST WINDS EXPECTED TO BEGIN AT RAWLINS AND LARAMIE AFTER 16Z...PERSISTING THROUGH THE AFTERNOON. PILOTS WILL MOST LIKELY SEE TURBULENT CONDITIONS FLYING OVER HIGHER TERRAIN FROM CHEYENNE WEST THROUGH THE AFTERNOON. CLAYCOMB && .PREV DISCUSSION... /ISSUED 949 PM MDT WED OCT 12 2011/ UPDATE... LOWERED OVERNIGHT MINS TO MORE ACCURATELY REPRESENT RECENT HOURLY TRENDS. KNOCKED SEVERAL DEGREES OFF OVERNIGHT LOWS. UPDATES HAVE BEEN SENT. CLAYCOMB PREV DISCUSSION... /ISSUED 524 PM MDT WED OCT 12 2011/ AVIATION...00Z TAFS WINDY CONDITIONS EXPECTED TO TAPER OFF SHORTLY AFTER 00Z THIS EVENING. GUSTY WEST TO NORTHWEST WINDS EXPECTED TO RETURN THURSDAY A COUPLE HOURS AFTER SUNRISE WITH MAINLY CLEAR SKIES. WINDY CONDITIONS EXPECTED TO CONTINUE THROUGH THE WEEK. CLAYCOMB PREV DISCUSSION... /ISSUED 351 PM MDT WED OCT 12 2011/ SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT...CURRENT OBSERVATIONS ACROSS SOUTHEAST WYOMING AND WESTERN NEBRASKA SHOW PARTLY CLOUDY SKIES AND WINDY CONDITIONS AS AN UPPER LEVEL TROUGH MOVES EASTWARD ACROSS THE GREAT PLAINS. WEST TO NORTHWEST WINDS HAVE GUSTED TO 50 MPH ACROSS PORTIONS OF SOUTHEAST WYOMING THIS AFTERNOON AND UP TO 40 MPH ACROSS WESTERN NEBRASKA. THE UPPER LEVEL TROUGH AND ASSOCIATED PRESSURE GRADIENT WILL PUSH EAST OF THE AREA BY THIS EVENING...RESULTING IN DIMINISHING WIND SPEEDS OVERNIGHT. MODELS SHOW THE UPPER LEVEL HIGH PRESSURE OFF THE CALIFORNIA COASTLINE NUDGING EASTWARD TOWARDS MEXICO AND THE BAJA PENINSULA THROUGH FRIDAY. EXPECT TEMPERATURES TO WARM ABOVE NORMAL ACROSS MOST OF THE AREA THURSDAY AND FRIDAY...WITH THE COOLEST TEMPS NORTH OF THE NORTH PLATTE RIVER VALLEY DUE TO THE POSITION OF THE JET STREAM. 120KT JET WILL REMAIN RELATIVELY STATIONARY OVER MONTANA AND NORTHERN WYOMING LATE THIS WEEK. WITH STRONG WINDS ALOFT...WINDY CONDITIONS ARE EXPECTED TO CONTINUE...ESPECIALLY ALONG AND WEST OF THE LARAMIE RANGE THROUGH FRIDAY. A SURFACE HIGH WILL DRIFT INTO THE CENTRAL PLAINS BY FRIDAY...RESULTING IN LIGHTER WINDS AND EAST TO SOUTHEAST FLOW NEAR THE SURFACE ACROSS WESTERN NEBRASKA. THE MAIN FORECAST CONCERN WILL BE LATE FRIDAY NIGHT AS THE NEXT COLD FRONT APPROACHES THE AREA AND A LEE SIDE TROUGH DEVELOPS OVER THE HIGH PLAINS. STRONG WINDS ARE POSSIBLE ACROSS SOUTHEAST WYOMING BY SATURDAY MORNING...ESPECIALLY IN THE WIND PRONE AREAS WITH GUSTS AROUND 55 MPH EXPECTED. LONG TERM...SATURDAY THROUGH WEDNESDAY. MODELS IN DECENT AGREEMENT ON THE 500 MB SYNOPTIC PATTERN...THUS HIGH CONFIDENCE IN THEIR RESPECTIVE SOLUTIONS. SATURDAY...MILD DAY WITH HIGH TEMPERATURES IN THE 60S AND 70S IN THE PRE-FRONTAL WARM AIRMASS AHEAD OF THE NEXT PASSING COLD FRONT THAT PASSES IN THE AFTERNOON. LOOKS LIKE ENOUGH LOW AND MID LEVEL MOISTURE FOR ISOLATED AFTERNOON SHOWERS ACROSS THE NORTHERN LARAMIE...SNOWY AND SIERRA MADRE RANGES. SUNDAY...ANOTHER QUICK MOVING SHORTWAVE ON THE HEELS OF THE SATURDAY SHORTWAVE WILL PRODUCE ISOLATED SHOWERS NEAR THE MOUNTAINS WEST OF A LUSK TO LARAMIE LINE...DRY ELSEWHERE. COOLER WITH HIGH IN THE 50S AND LOWER 60S IN THE WAKE OF THE COLD FRONT. MONDAY...COOL DAY WITH SURFACE HIGH BUILDING SOUTH ACROSS THE NORTHERN AND CENTRAL ROCKIES. ISOLATED SHOWERS NEAR OUR WESTERN MOUNTAINS WITH SOME MID LEVEL MOISTURE AND OROGRAPHICS...DRY ELSEWHERE. TUESDAY...TRANSITORY RIDGE ALOFT MOVES TO WYOMING WITH A WARMING TREND AS RETURN SOUTH WINDS DEVELOP. DRY DUE TO LACK OF LOW AND MID LEVEL MOISTURE. WEDNESDAY...ANOTHER FAST MOVING SHORTWAVE WILL SPREAD CLOUDS ACROSS THE COUNTIES...THOUGH TIMING THESE SHORTWAVES IN THE PROGRESSIVE PATTERN ALOFT WILL BE DIFFICULT AT BEST AT THIS JUNCTURE. AS IS TYPICAL WITH THESE FAST MOVING SYSTEMS THAT HAVE LIMITED MOISTURE... WILL LIKELY SEE LITTLE IF ANY PRECIPITATION WITH THIS SHORTWAVE TROUGH PASSAGE. AVIATION...18Z TAFS. WEST TO NORTHWEST WINDS OF 20 TO 35 MPH WITH LOCALIZED GUSTS TO 45 MPH THROUGH 22Z...PRODUCING LOCALIZED MOUNTAIN AND HILL TURBULENCE AND LEE EDDY EFFECTS DOWNWIND OF SLOPES. WINDS DECREASING AFTER 22Z. WEST WINDS INCREASING TO 20 TO 35 MPH WITH GUSTS TO 45 MPH ACROSS SOUTHEAST WYOMING AFTER 15Z THURSDAY. VFR WITH SCATTERED TO BROKEN CLOUD DECK AT OR ABOVE 8000 FEET ABOVE GROUND LEVEL. FIRE WEATHER...FIRE WEATHER CONCERNS WILL REMAIN MODERATE INTO THIS WEEKEND...MAINLY DUE TO GUSTY WEST TO NORTHWEST WINDS...WHICH WILL SUBSIDE OVER THE HIGH PLAINS EAST OF THE LARAMIE RANGE ON FRIDAY. DAYTIME HUMIDITIES WILL LOWER TO AROUND 20 PERCENT ON SATURDAY AHEAD OF THE NEXT COLD FRONT. COOLER TEMPS AND HIGHER HUMIDITIES ARE EXPECTED ON SUNDAY THROUGH EARLY NEXT WEEK. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && SHORT TERM...TJT LONG TERM/AVIATION...CLAYCOMB
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE CHEYENNE WY 423 AM MDT WED OCT 12 2011 WYZ101>119-131030- CONVERSE COUNTY LOWER ELEVATIONS-NIOBRARA COUNTY- NORTH LARAMIE RANGE-FERRIS/SEMINOE/SHIRLEY MOUNTAINS- SHIRLEY BASIN-CENTRAL LARAMIE RANGE AND SOUTHWEST PLATTE COUNTY- EAST PLATTE COUNTY-GOSHEN COUNTY-CENTRAL CARBON COUNTY- NORTH SNOWY RANGE FOOTHILLS-SOUTHWEST CARBON COUNTY- SIERRA MADRE RANGE-UPPER NORTH PLATTE RIVER BASIN-SNOWY RANGE- LARAMIE VALLEY-SOUTH LARAMIE RANGE-SOUTH LARAMIE RANGE FOOTHILLS- CENTRAL LARAMIE COUNTY-EAST LARAMIE COUNTY- 423 AM MDT WED OCT 12 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL WYOMING... SOUTH CENTRAL WYOMING AND SOUTHEAST WYOMING. .DAY ONE...TODAY AND TONIGHT WEST TO SOUTHWEST WINDS WILL GUST AS HIGH AS 50 MPH TODAY IN THE ARLINGTON AREA AS WELL AS OVER AND NEAR THE LARAMIE RANGE. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY BREEZY CONDITIONS WILL CONTINUE THROUGH THE WEEKEND IN THE WIND CORRIDOR ALONG AND WEST OF THE LARAMIE RANGE...WITH THE NEXT TIME FRAME FOR STRONGER WINDS LIKELY TO BE ON SATURDAY. THE NEXT CHANCE OF PRECIPITATION WILL BE SUNDAY AND MONDAY WITH THE PASSAGE OF A STRONG COLD FRONT. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY AND TONIGHT. && THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGIC...AND CLIMATE INFORMATION IS AVAILABLE ON THE WEB AT... HTTP://WEATHER.GOV/CHEYENNE NEZ002-003-019>021-054-055-095-096-131030- DAWES-BOX BUTTE-SCOTTS BLUFF-BANNER-MORRILL-KIMBALL-CHEYENNE- NORTH SIOUX-SOUTH SIOUX- 423 AM MDT WED OCT 12 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE WESTERN NEBRASKA PANHANDLE. .DAY ONE...TODAY AND TONIGHT WINDY CONDITIONS WILL OCCUR THIS AFTERNOON WITH NORTHWEST WINDS OF 20 TO 30 MPH GUSTING UP TO 40 MPH. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY THE NEXT CHANCE OF PRECIPITATION AND WINDY CONDITIONS WILL BE LATE SUNDAY NIGHT AND MONDAY WITH THE PASSAGE OF A COLD FRONT. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY AND TONIGHT. && THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGIC...AND CLIMATE INFORMATION IS AVAILABLE ON THE WEB AT... HTTP://WEATHER.GOV/CHEYENNE
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHEYENNE WY 1156 PM MDT WED OCT 12 2011 WYZ114-130900- SNOWY RANGE- INCLUDING THE CITIES OF...CENTENNIAL...ALBANY...WOODS LANDING 1156 PM MDT WED OCT 12 2011 ...STRONG WINDS ON THE EAST SLOPES OF THE SNOWY RANGE EXPECTED OVERNIGHT... WEST WINDS OF 30 TO 40 MPH WITH GUSTS TO 65 MPH WILL OCCUR ACROSS THE EASTERN SLOPES OF THE SNOWY RANGE OVERNIGHT...AND WILL BEGIN TO EASE AROUND SUNRISE. LOCATIONS THAT MAY EXPERIENCE THESE STRONG WINDS INCLUDE CENTENNIAL...THE SNOWY RANGE SKI AREA...HIGHWAY 130 OVER THE SNOWY RANGE AND THE SNOWY RANGE PASS. IF YOU ARE IN THESE AREAS...BE PREPARED FOR THESE STRONG AND GUSTY WEST WINDS...ESPECIALLY ALONG EXPOSED LOCATIONS ALONG THE EASTERN SLOPES OF THE SNOWY RANGE. WYZ110-130900- NORTH SNOWY RANGE FOOTHILLS- INCLUDING THE CITIES OF...ARLINGTON...ELK MOUNTAIN 1156 PM MDT WED OCT 12 2011 ...GUSTY WINDS EXPECTED OVERNIGHT IN EASTERN CARBON COUNTY... SOUTHWEST WINDS OF 25 TO 35 MPH WITH GUSTS TO 55 MPH WILL OCCUR OVERNIGHT ESPECIALLY IN THE WIND PRONE AREAS ALONG THE INTERSTATE 80 CORRIDOR NEAR ARLINGTON. WIND SPEEDS WILL BEGIN TO EASE AROUND SUNRISE. THE WYOMING DEPARTMENT OF TRANSPORTATION ADVISES NO LIGHT TRAILER TRAFFIC DUE TO WIND SPEEDS ABOVE 50 MPH. THESE WINDS MAY CAUSE LOSS OF VEHICLE CONTROL OR A BLOW OVER TO HIGH PROFILE VEHICLES TRAVELING EMPTY OR WITH A LIGHT LOAD. DRIVERS OF SUCH VEHICLES ARE ADVISED TO DELAY TRAVEL.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHEYENNE WY 139 AM MDT THU OCT 13 2011 WYZ114-131000- SNOWY RANGE- INCLUDING THE CITIES OF...CENTENNIAL...ALBANY...WOODS LANDING 139 AM MDT THU OCT 13 2011 ...STRONG WINDS ON THE EAST SLOPES OF THE SNOWY RANGE EXPECTED OVERNIGHT... WEST WINDS OF 25 TO 35 MPH WITH GUSTS TO 55 MPH WILL OCCUR ACROSS THE EASTERN SLOPES OF THE SNOWY RANGE OVERNIGHT...AND EASE BY SUNRISE. LOCATIONS THAT MAY EXPERIENCE THESE STRONG WINDS INCLUDE CENTENNIAL...THE SNOWY RANGE SKI AREA...HIGHWAY 130 OVER THE SNOWY RANGE AND THE SNOWY RANGE PASS. IF YOU ARE IN THESE AREAS...BE PREPARED FOR THESE STRONG AND GUSTY WEST WINDS...ESPECIALLY ALONG EXPOSED LOCATIONS ALONG THE EASTERN SLOPES OF THE SNOWY RANGE. WYZ110-131000- NORTH SNOWY RANGE FOOTHILLS- INCLUDING THE CITIES OF...ARLINGTON...ELK MOUNTAIN 139 AM MDT THU OCT 13 2011 ...GUSTY WINDS EXPECTED OVERNIGHT IN EASTERN CARBON COUNTY... SOUTHWEST WINDS OF 25 TO 35 MPH WITH GUSTS TO AROUND 45 MPH WILL OCCUR OVERNIGHT ESPECIALLY IN THE WIND PRONE AREAS ALONG THE INTERSTATE 80 CORRIDOR NEAR ARLINGTON. WIND SPEEDS WILL EASE BY SUNRISE. PEOPLE DRIVING HIGH PROFILE VEHICLES SHOULD BE ESPECIALLY CAUTIOUS AND ALERT TO THE GUSTY WEST AND SOUTHWEST WINDS...ESPECIALLY IN THE TYPICAL WIND PRONE LOCATIONS.
The national radar mosaic for the moment the first event began.
1 high wind. Local standard time, as filed.
WYDOT sensors across the Northern Snowy Range measured sustained winds in excess of 40 mph and a peak gust of 62 mph.
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, October 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: 346138.