A tight pressure gradient combined with strong upper level winds produced strong surface winds during the morning hours.
Every event with a place to put it; 2 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.
A tight pressure gradient combined with strong upper level winds produced strong surface winds during the morning 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 Nov 20, 3:04 AM MST, 2 hours 47 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHEYENNE WY 304 AM MST SAT NOV 20 2010 .SHORT TERM...TODAY THROUGH SUNDAY NIGHT... SFC BOUNDARY OVER THE CWA ALONG THE MTNS WILL MEANDER OVER THE NEXT COUPLE OF DAYS...SLIPPING A LITTLE EASTWARD THIS AFTERNOON AND TONIGHT BEFORE SAGGING BACK WESTWARD SUNDAY. TEMPS A LITTLE TRICKY DEPENDING ON POSITION OF THE FRONT WITH WARMEST READINGS EXPECTED OVER FAR SE WY...THOUGH SRLY WINDS TODAY MAY HOLD CLOUDS IN PLACE OVER PARTS OF THE EASTERN CWA WHICH WOULD RETARD WARMING. SOME FOG WILL EXIST MAINLY OVER THE CHEYENNE RIDGE THIS MORNING FROM ABOUT CHEYENNE TO KIMBALL DUE TO LOCAL UPLIFT OF SOUTHERLY SFC FLOW. OTHERWISE GENERALLY MILD TO COOL CONDITIONS EXPECTED ACROSS THE CWA TODAY THROUGH SUNDAY AS PLENTY OF CLOUDINESS ADVECTS ACROSS THE AREA ON SW FLOW ALOFT. ONE SHORTWAVE WILL EJECT NORTHEAST ACROSS THE CWA TONIGHT AND WILL BRING SOME SNOW TO MAINLY THE HIGHER MTNS LATER TONIGHT INTO SUNDAY. SOME DECENT SNOWS EXPECTED ON THE SW FACING SLOPES OF THE SIERRA MADRES BUT BETTER QPF LOOKS TO STAY MORE ACROSS COLORADO THUS HAVE DECIDED TO HOLD OFF FROM HILITES AT THIS TIME. BIT OF A LULL LATE SUNDAY MORNING INTO THE AFTERNOON BEFORE NEXT STRONGER SHOT OF ENERGY RIDES ACROSS THE CWA SUNDAY NIGHT. THIS SHOULD SPREAD SOME SNOW OVER THE PLAINS...ESPECIALLY NORTH AND EAST OF WHEREVER THE SFC BOUNDARY EXISTS WITH MOST FAVORED AREAS FOR SOME ACCUMULATIONS CURRENTLY OVER NORTHERN PORTIONS OF THE CWA. .LONG TERM...MONDAY THROUGH SATURDAY... BROAD WESTERN NOAM TROUGH WILL CONTINUE TO BE STRENGTHENED AS SHORTWAVES ROTATE AROUND THE HUDSON BAY VORTEX. MEDIUM RANGE GUIDANCE IN FAIR AGREEMENT ON THE GENERAL LONGWAVE PATTERN PROGRESSION...BUT DIFFER ON THE TIMING AND STRENGTH OF INDIVIDUAL SHORTWAVES. INITIAL H5 SHORTWAVE WILL MOVE EAST INTO THE HIGH PLAINS BY MONDAY...GIVING WAY TO DRY CONDITIONS EAST...AND CONTINUED OROGRAPHIC MOUNTAIN SNOWS WEST. BY TUESDAY/TUESDAY NIGHT...THE NEXT SHORTWAVE SWINGS AROUND THE BASE OF THE MEAN TROUGH INTO IDAHO. MODEL DIFFERENCES EXIST ON THE EXACT TRAJECTORY/TIMING OF THIS FEATURE 00Z GFS THE QUICKEST MOVING IT INTO THE DAKOTAS BY EARLY WEDNESDAY. MEANWHILE...THE GFS/GEM ARE SLOWER KEEPING THE ENERGY ACROSS WY/MT ON WEDNESDAY A.M. FOR NOW...HAVE GENERALLY FOLLOWED THE GFS/GEM WHICH INCREASES SNOW CHANCES IN THE WEST ON TUESDAY...SPILLING OUT ONTO THE EASTERN PLAINS ON TUESDAY NIGHT AS A STRONG COLD FRONT BLASTS THROUGH. AREA MOUNTAINS WILL PROBABLY NEED A WINTER HIGHLIGHT IN DUE TIME FOR THIS PERIOD. TEMPERATURES WILL RUN 5 TO 10 DEGREES BELOW AVERAGE ON MONDAY AND TUESDAY...BUT WILL FEEL WARM BY WEDNESDAYS STANDARDS. H7 TEMPERATURES WILL DROP TO NEAR -20C BEHIND TUESDAY NIGHTS COLD FRONT...WHICH WILL YIELD HIGH TEMPERATURES THAT WILL STRUGGLE TO CLIMB OUT OF THE SINGLE DIGITS NORTH AND WEST...AND TEENS SOUTH AND EAST. MID-LEVEL HEIGHTS WILL GRADUALLY RISE FOR THURSDAY THROUGH SATURDAY...YIELDING DRY CONDITIONS WITH MODERATING TEMPERATURES BACK INTO THE 40S AND 50S BY SATURDAY. && .AVIATION...12Z TAF ISSUANCE... SOUTHERLY WIND AT THE SURFACE HAS RESULTED IN LIFR/IFR CIGS/VSBYS AT KCYS AND KSNY THIS MORNING. ELSEWHERE...MVFR CIGS HAVE BEEN OBSERVED AT KBFF...KCDR...AND KAIA. VFR CONDITIONS HAVE PREVAILED ELSEWHERE. THIS AREA OF FOG/LOW CLOUDS WILL GRADUALLY LIFT BACK TO VFR BY MID/LATE MORNING. VFR CONDITIONS ARE ANTICIPATED THROUGH THE REMAINDER OF THE TAF PERIOD. WINDS WILL BE FAIRLY LIGHT AT AIRPORTS EAST OF THE MOUNTAINS. BREEZY SOUTHWEST CONDITIONS WITH GUSTS TO AROUND 25 KNOTS CAN BE EXPECTED AT KRWL AND KLAR THROUGH SUNSET BEFORE RELAXING. && .FIRE WEATHER... RATHER STRONG AND GUSTY WINDS WILL OCCUR TODAY INTO SUNDAY OVER WESTERN DISTRICTS BUT NO REAL FIRE WEATHER CONCERNS AS HUMIDITIES WILL REMAIN WELL ABOVE CRITICAL THRESHOLDS THROUGH SUNDAY AND FUELS NOT CRITICALLY DRY. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && SHORT TERM/FIRE WEATHER...RE LONG TERM/AVIATION...HAHN
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE CHEYENNE WY 525 PM MST FRI NOV 19 2010 NEZ002-003-019>021-054-055-095-096-WYZ101-102-107-108-118-119- 202215- DAWES-BOX BUTTE-SCOTTS BLUFF-BANNER-MORRILL-KIMBALL-CHEYENNE- NORTH SIOUX-SOUTH SIOUX-CONVERSE COUNTY LOWER ELEVATIONS- NIOBRARA COUNTY-EAST PLATTE COUNTY-GOSHEN COUNTY- CENTRAL LARAMIE COUNTY-EAST LARAMIE COUNTY- 525 PM MST FRI NOV 19 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE WESTERN NEBRASKA PANHANDLE...SOUTHEAST WYOMING. .DAY ONE...TONIGHT NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY THERE WILL CHANCES FOR MAINLY LIGHT SNOW FROM SATURDAY NIGHT THROUGH TUESDAY NIGHT. MUCH COLDER AIR WILL INVADE THE AREA TUESDAY NIGHT AND WEDNESDAY...WITH TEMPERATURES WEDNESDAY MORNING POSSIBLY FALLING BELOW ZERO IN SOME AREAS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TONIGHT. && THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGIC...AND CLIMATE INFORMATION IS AVAILABLE ON THE WEB AT... HTTP://WEATHER.GOV/CHEYENNE WYZ103>106-109>117-202215- NORTH LARAMIE RANGE-FERRIS/SEMINOE/SHIRLEY MOUNTAINS- SHIRLEY BASIN-CENTRAL LARAMIE RANGE AND SOUTHWEST PLATTE 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- 525 PM MST FRI NOV 19 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL WYOMING... SOUTH CENTRAL WYOMING AND SOUTHEAST WYOMING. .DAY ONE...TONIGHT NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY GUSTY SOUTHWEST WINDS UP TO 40 MPH WILL AGAIN OCCUR OVER AND WEST OF THE LARAMIE RANGE SATURDAY. THERE WILL CHANCES FOR SNOW FROM SATURDAY AFTERNOON THROUGH TUESDAY NIGHT. MUCH COLDER AIR WILL INVADE THE AREA TUESDAY NIGHT AND WEDNESDAY...WITH TEMPERATURES WEDNESDAY MORNING POSSIBLY FALLING BELOW ZERO IN SOME AREAS. WINDS WILL STRENGTHEN ON THURSDAY...INCREASING THE POTENTIAL FOR BLOWING SNOW CONDITIONS ACROSS THE AREA. TRAVEL COULD BECOME HAZARDOUS THROUGH THE DAY WITH SLICK ROADS RESULTING FROM THE BLOWING SNOW. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TONIGHT. && THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGIC...AND CLIMATE INFORMATION IS AVAILABLE ON THE WEB AT... HTTP://WEATHER.GOV/CHEYENNE COX
The national radar mosaic for the moment the first event began.
2 high wind. Local standard time, as filed.
The sensor at Arlington on I-80 reported sustained winds in excess of 40 mph during this time frame, with a peak gust of 69 mph at 656LST.
Reported from the Skyline sensor southeast of Encampment.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2010Every state in 2010This day in weather historyWarnings in Wyoming, November 2010
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: 263428, 263426.