A strong surface pressure gradient produced strong winds in the wind prone areas of southeast Wyoming.
Every event with a place to put it; 3 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 strong surface pressure gradient produced strong winds in the wind prone areas of southeast Wyoming.
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 Feb 9, 10:30 AM MST, 35 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHEYENNE WY 1030 AM MST WED FEB 9 2011 .UPDATE... UPDATE FOR 18Z TAF ISSUANCE. ALSO TO CANCEL WIND CHILL WARNING BUT ADD HIGH WIND WARNING DUE TO EXPECTED STRONG WINDS AROUND ARLINGTON SND SOUTHERN PLATTE COUNTY. .PREVIOUS DISCUSSION... .SHORT TERM...TODAY THROUGH THURSDAY NIGHT...WIDESPREAD FRIGID TEMPS ARE OCCURRING OVERNIGHT...WITH WIND CHILLS IN THE MINUS 20S TO MINUS 30S FOR MOST OF THE AREA WITH A FEW SPOTS A LITTLE LESS BRUTAL IN THE MINUS TEENS. WINDS RANGE MOSTLY FROM THE SOUTHWEST TO NORTHWEST NOW AND ROUGHLY 5 TO 10 MPH...WITH SLIGHTLY HIGHER WINDS AT KBRX. THIS SHOULD HELP KEEP TEMPS FROM TANKING MUCH FURTHER DUE TO THE DOWNSLOPE COMPONENT. WINDS WILL REMAIN STEADY...OR SLIGHTLY INCREASE THROUGH THE MORNING AS THE 1040 MB SURFACE HIGH SLIDES OVERHEAD THAN SOUTHWEST OF THE REGION AND TIGHTENS THE LLVL PRESSURE GRADIENT A BIT. THIS WILL KEEP WIND CHILLS DANGEROUSLY COLD THROUGH THE MORNING...SO WILL MAINTAIN THE HIGHLIGHT AS IS. THE MAIN UPPER TROUGH AFFECTING THE REGION WITH SNOW AND COLD WILL SLOWLY BEGIN TO SHIFT EAST TODAY...AS AN UPPER LEVEL RIDGE BUILDS IN ITS WAKE. STEADILY RISING HEIGHTS AND DOWNSLOPE WINDS WILL ALLOW TEMPERATURES TO RECOVER QUITE A BIT TODAY BACK INTO THE 20S EAST OF THE LARAMIE RANGE...WITH TEENS REMAINING IN THE HIGH VALLEYS OF CARBON AND ALBANY COUNTIES AS THE INVERSION WILL BE TOUGH TO BREAK. LOOKS LIKE THE NW FLOW PATTERN TYPICAL OF WARM BUT WINDY CONDITIONS WILL RETURN TONIGHT AND CONTINUE THROUGH FRIDAY NIGHT. WINDS WILL BECOME QUITE STRONG TOMORROW IN THE WIND CORRIDOR AS HIGH PRESSURE STRENGTHENS AT THE SFC AND ALOFT. WINDS ALOFT ARE NOT ALL THAT STRONG...WITH 35 TO 40 KTS PROGGED AT 700 MB BY 18Z THURS. A CROSS SECTION OF LAPSE RATES AND OMEGA ACROSS THE WIND CORRIDOR SHOWS LLVL SUBSIDENCE BELOW A STABLE LAYER JUST ABOVE THE MOUNTAIN TOPS SETTING UP FOR THURSDAY THROUGH FRIDAY MORNING. AGAIN...UPPER WINDS LOOK MARGINAL FOR HIGH WIND GUST CRITERIA BUT WOULD NOT BE SURPRISED IF SUSTAINED WINDS PERIODICALLY REACH 40 MPH...WITH A GUST OR TWO UP TO 60 MPH A REAL POSSIBILITY. SO WILL KEEP A CLOSE WATCH ON THIS MARGINAL EVENT...WITH A KEEN EYE TO BE PLACED ON HOW STRONG THE SFC HIGH SETS UP OVER NW COLORADO AND THUS THE RESULTANT LLVL PRESSURE GRADIENT. A FEW MOUNTAIN SNOW SHOWERS ARE POSSIBLE IN THIS FLOW PATTERN...WITH SOME PATCHY FOG AND LOW CLOUDS LIKELY IN THE FAR WESTERN VALLEYS OF CARBON COUNTY DURING THE OVERNIGHT AND EARLY MORNING HOURS AS WELL. OTHERWISE...WILL REMAIN DRY. .LONG TERM...FRIDAY THROUGH TUESDAY... THE MEDIUM RANGE MODELS ARE IN GOOD AGREEMENT THAT THE WARMING TREND WILL CONTINUE LATE IN THE WEEK AND THROUGH THE WEEKEND...WITH NO SIGNIFICANT PRECIPITATION PRODUCING SYSTEMS EXPECTED ACROSS THE AREA. TEMPERATURES WILL BE SLIGHTLY ABOVE NORMAL ACROSS MUCH OF THE AREA FRIDAY...AND THEN WILL WARM TO AROUND 10 TO 15 DEGREES ABOVE NORMAL BY SUNDAY. A WEAK DRY COLD FRONT WILL MOVE ACROSS THE AREA SUNDAY NIGHT OR EARLY MONDAY...BUT MONDAY HIGH TEMPERATURES WILL STILL BE AROUND 10 DEGREES ABOVE NORMAL. HAVE ADJUSTED CONSENSUS WIND SPEEDS UP SLIGHTLY AT THE ARLINGTON AND BORDEAUX AREAS AGAIN...ESPECIALLY FOR THE SATURDAY- SUNDAY AND TUESDAY PERIODS. && .AVIATION...18Z TAF ISSUANCE... VFR CONDITIONS WILL PREVAIL ACROSS MUCH OF THE AREA THROUGH THURSDAY BUT SOME INCREASE IN MOISTURE COULD PRODUCE SOME MAINLY MVFR CIGS VCTY KRWL LATER TONIGHT INTO THURSDAY. -RE- && .FIRE WEATHER...NO FIRE WEATHER CONCERNS EXPECTED IN THE NEAR TERM DUE TO RECENT COLD TEMPERATURES AND SNOWFALL. WESTERLY WINDS WILL BE ON THE INCREASE TONIGHT THROUGH THE END OF THE WEEK...BUT EXPECT SUFFICIENT LOW LEVEL MOISTURE FROM RECENT STORM SYSTEMS TO KEEP FIRE WEATHER THREAT LOW. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...HIGH WIND WARNING UNTIL 9 AM THURSDAY FOR FOR WYZ106-WYZ110. NE...NONE. && SHORT TERM/FIRE WEATHER...RJM LONG TERM/AVIATION...CARPENTER
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE CHEYENNE WY 1024 AM MST WED FEB 9 2011 WYZ101>119-101730- 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- 1024 AM MST WED FEB 9 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST WYOMING. .DAY ONE...TODAY AND TONIGHT TONIGHT TEMPERATURES WILL NOT BE AS COLD AS THIS MORNING...BUT WIND CHILLS ARE EXPECTED TO DROP TO AROUND 10 BELOW TO 20 BELOW ZERO AGAIN TONIGHT. LOCALLY STRONG WINDS ARE EXPECTED TO DEVELOP IN THE WIND PRONE AREAS OF WYOMING TODAY...WITH GUSTS UP TO 60 MPH POSSIBLE. A HIGH WIND WARNING IS NOW IN EFFECT FOR SOUTHEAST PLATTE COUNTY ALONG WITH EASTERN CARBON COUNTY THROUGH TONIGHT. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY STRONG AND GUSTY WINDS WILL BE POSSIBLE OVER THE WEEKEND AND TUESDAY...ALONG WITH ABOVE NORMAL TEMPERATURES. .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>021-054-055-095-096-101730- DAWES-BOX BUTTE-SCOTTS BLUFF-BANNER-MORRILL-KIMBALL-CHEYENNE- NORTH SIOUX-SOUTH SIOUX- 1024 AM MST WED FEB 9 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE WESTERN NEBRASKA PANHANDLE. .DAY ONE...TODAY AND TONIGHT TONIGHT TEMPERATURES WILL NOT BE AS COLD AS THIS MORNING...BUT WIND CHILLS ARE EXPECTED TO DROP TO AROUND 10 BELOW TO 20 BELOW ZERO AGAIN TONIGHT. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .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 TT
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHEYENNE WY
617 AM MST WED FEB 09 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0553 AM EXTR WIND CHILL ALLIANCE 42.10N 102.87W
02/09/2011 M-32 F BOX BUTTE NE ASOS
WIND CHILLS HAVE BEEN LESS THAN -30F PERIODICALLY THROUGH
THE NIGHT.
&&
MAZURPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHEYENNE WY
618 AM MST WED FEB 09 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0555 AM EXTR WIND CHILL SARATOGA 41.45N 106.81W
02/09/2011 M-33 F CARBON WY AWOS
&&
MAZURPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHEYENNE WY
626 AM MST WED FEB 09 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0542 AM EXTR WIND CHILL 13 W HARRISBURG 41.55N 103.99W
02/09/2011 M-33 F BANNER NE MESONET
MEASURED BY THE BRAVO 01 RAWS.
&&
MAZURPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHEYENNE WY
646 AM MST WED FEB 09 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0553 AM EXTR WIND CHILL LARAMIE 41.31N 105.58W
02/09/2011 M-41 F ALBANY WY ASOS
&&
BCHAPMANPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHEYENNE WY
655 AM MST WED FEB 09 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0553 AM EXTR WIND CHILL DOUGLAS 42.76N 105.39W
02/09/2011 M-35 F CONVERSE WY ASOS
&&
BCHAPMANPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHEYENNE WY
658 AM MST WED FEB 09 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0653 AM EXTR WIND CHILL SCOTTSBLUFF 41.87N 103.66W
02/09/2011 M-31.00 F SCOTTS BLUFF NE ASOS
&&
BCHAPMANThe national radar mosaic for the moment the first event began.
3 high wind. Local standard time, as filed.
WYDOT sensor at Bordeaux measured sustained winds in excess of 40 mph throughout the event.
WYDOT sensor at Arlington measured sustained winds in excess of 40 mph throughout the event with a peak gust of 67 mph 10/0721 AM.
WYDOT sensor at Bordeaux measured sustained winds in excess of 40 mph for a few hours.
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, February 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: 276836, 276837, 276838.