Strong winds aloft combined with a tight surface pressure gradient to produce strong southwest winds in portions of southeast Wyoming.
Every event with a place to put it; 7 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 aloft combined with a tight surface pressure gradient to produce strong southwest winds in portions 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 Mar 9, 9:45 PM MST, 1 hour 25 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHEYENNE WY 945 PM MST WED MAR 9 2011 .UPDATE... THE EVENING WATER VAPOR IMAGERY SHOWED A MID/UPPER RIDGE AXIS FROM THE DESERT SOUTHWEST TO THE NORTHERN ROCKIES AND TROUGH AXIS ALONG THE MISSISSIPPI RIVER VALLEY. THE FLOW ALOFT BETWEEN THESE FEATURES WAS NORTHWESTERLY OVER THE CWA. THE REGIONAL SURFACE ANALYSIS DEPICTED HIGH PRESSURE OVER THE NORTHERN/CENTRAL PLAINS AND ACROSS COLORADO/UTAH. A LEE LOW PRESSURE TROUGH REACHED FROM NORTHERN WYOMING INTO NORTH CENTRAL COLORADO. THE GRADIENT WAS SLOWLY TIGHTENING THIS EVENING...WITH MEDICINE BOW PROFILER WINDS AT THE LOWEST GATE BETWEEN 40 AND 45 KT. SUSTAINED WINDS AT ARLINGTON HAVE BEEN CONSISTENTLY AROUND 30 KT WITH GUSTS TO 40 KT. BORDEAUX/S WINDS WERE TRENDING UP AS WELL. THE HIGH WIND WARNING FOR THESE AREAS WILL REMAIN IN EFFECT TONIGHT. SOME MID/HIGH CLOUDS WERE PASSING QUICKLY FROM NORTHWEST TO SOUTHEAST. TEMPERATURES AT 9 PM WERE AVERAGING 3-5 DEGREES ABOVE GUIDANCE... ESPECIALLY OVER THE NORTHERN NEBRASKA PANHANDLE AND SOUTHEAST WYOMING ZONES EAST OF THE LARAMIE RANGE. HAVE RAISED TEMPERATURES IN THESE AREAS. && .AVIATION...06Z TAF ISSUANCE VFR CONDITIONS WILL PREVAIL DURING THE NEXT 24 HOURS WITH INTERVALS OF SCATTERED MID/HIGH CLOUDS. WEST TO SOUTHWEST SURFACE WINDS WILL BE STRONG AND GUSTY OVER AND WEST OF THE LARAMIE RANGE...WITH GUSTS AS HIGH AS 50 KT LATER TONIGHT AND EARLY THURSDAY MORNING. ACROSS THE WESTERN NEBRASKA PANHANDLE...NORTHWEST TO WEST SURFACE WINDS WILL GENERALLY AVERAGE AROUND 10 KT. && .PREV DISCUSSION... /ISSUED 327 PM MST WED MAR 9 2011/ SHORT TERM...TONIGHT THROUGH FRIDAY...THE MAIN FORECAST ISSUE FOR THE NEAR TERM WILL BE THE RETURN OF STRONG WESTERLY WINDS. IN THE BIG PICTURE...A RIDGE OF HIGH PRESSURE WILL BUILD OVER THE AREA TONIGHT AND TOMORROW...WITH AN UPPER LEVEL DISTURBANCE TO MOVE ACROSS THE NORTHERN ROCKIES AND PLAINS THURSDAY NIGHT AND FRIDAY. FOR TONIGHT...ISSUED A HIGH WIND WARNING FOR THE ARLINGTON AND BORDEAUX AREA AS ALREADY BREEZY WINDS TODAY ARE EXPECTED TO INCREASE TONIGHT. A CROSS SECTION PROFILE OF THE WIND CORRIDOR FROM NEAR ARLINGTON TO BORDEAUX SHOWS A STRENGTHENING STABLE LAYER JUST ABOVE THE MOUNTAIN TOPS TONIGHT...AND THEN SUBSIDING TO THE SFC SO THAT THE TOP OF THE LAYER MAY BE JUST BELOW THE MOUNTAIN PEAKS BY MORNING. THE NAM AND ECMWF FORECASTS SHOW THE SFC PRESSURE GRADIENT TO BE CONDUCIVE OF HIGH SUSTAINED WINDS WITH 50 KT OF FLOW JUST OFF THE SURFACE LIKELY TO DEFLECT TOWARD THE SURFACE IN THAT LOW LEVEL STABLE LAYER. THE ONE NEGATIVE MAY BE THE STABLE LAYER RESIDING TOO CLOSE TO THE SURFACE...WHICH MAY NOT TRAP THE STRONG WINDS IN THAT SURFACE LAYER LIKE IN A TRUE GAP WIND EVENT. BUT FEEL CONFIDENT ENOUGH THAT THESE AREAS WILL HIT CRITERIA AT SOME POINT TONIGHT IN THIS PATTERN...WITH ARLINGTON LIKELY IN THE EARLY OVERNIGHT PERIOD AND BORDEAUX FOLLOWING SUIT THROUGH THE EARLY MORNING HOURS. IT WILL BE A MARGINAL EVENT...BUT WINDY NONETHELESS. A BRIEF LULL WILL OCCUR THURSDAY AFTERNOON AS THE UPPER RIDGE SHIFTS EAST AND THE UPPER WAVE APPROACHES. THE LEE SIDE SFC TROUGH WILL DEEPEN AHEAD OF THE SYSTEM...WITH SFC CYCLOGENESIS OCCURRING ACROSS THE DAKOTAS FRIDAY MORNING. THE ASSOCIATED COLD FRONT WILL SWING THROUGH OUR FORECAST AREA THROUGH THE LATER MORNING ON FRIDAY...WITH WESTERLY WINDS OUT AHEAD OF IT BECOMING MORE WIDESPREAD STRONG AND GUSTY. WILL LIKELY SEE THE WIND CORRIDOR PICK UP IN SPEED MORESO THURSDAY NIGHT AS WESTERLY 700MB WINDS INCREASE TO AROUND 65 KT. THEN CAN EXPECT THE EXPANSION OF STRONG WINDS EAST AND SOUTH ACROSS THE PLAINS OF WYOMING AND THE NEBRASKA PANHANDLE EARLY FRIDAY MORNING AHEAD OF THE MAIN FRONT. WITH THE CURRENT HIGHLIGHTS OUT...WILL HOLD OFF ON ISSUING A HIGH WIND WATCH. BUT AS IT STANDS...LOOKS LIKE MUCH OF THE WYOMING PORTION OF THE CWA AND THE SOUTHERN PANHANDLE ZONES MAY NEED A WARNING WITH A WIND ADVISORY IN THE NORTHERN PANHANDLE. IN ADDITION...SNOW/RAIN SHOWERS WILL PICK UP FRIDAY MORNING FOR THE WESTERN SLOPES AS THE 700MB WINDS INCREASE...AND THEN THE NORTHERN ZONES AS THE FRONT DROPS SOUTH. THE STRONG DOWNSLOPING WINDS WILL LIKELY KEEP SOUTHERN ZONES TOO DRY FOR PRECIP. LONG TERM...FRIDAY NIGHT THROUGH NEXT WEDNESDAY...MODELS IN GOOD AGREEMENT WITH THE OVERALL PATTERN...BUT DIFFER ON THE PLACEMENT AND EVOLUTION OF SHORTWAVE ACTIVITY EXPECTED TO QUICKLY MOVE EASTWARD FROM THE EASTERN PACIFIC OCEAN. ALL MODELS AND ENSEMBLES SHOW MAINLY ZONAL FLOW ACROSS THE ROCKY MOUNTAIN REGION AND WESTERN GREAT PLAINS THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. THE FIRST OF TWO UPPER LEVEL DISTURBANCES WILL APPROACH SOUTHEAST WYOMING AND WESTERN NEBRASKA BY SATURDAY. GFS...ECMWF AND DGEX ALL SHOW A WEAK PACIFIC FRONT PUSHING SOUTHWARD SATURDAY NIGHT RESULTING IN WINDY CONDITIONS AND A CHANCE OF PRECIP. EXPECT SNOW/RAIN IN THE LOWER ELEVATIONS AND SNOW IN THE MOUNTAINS AS THE BASE OF THE UPPER LEVEL TROUGH QUICKLY PUSHES EAST ACROSS WYOMING AND COLORADO. QPF AMOUNTS ARE EXPECTED TO BE LIGHT DUE TO THE QUICK MOVEMENT SPEED AND LACK OF DYNAMICS. THERE IS SOME LOW LEVEL INSTABILITY WITH THESE SYSTEMS AS THEY PUSH EASTWARD...SO CAN NOT RULE OUT SOME LOCALLY HEAVY SHOWER ACTIVITY ALONG THE MAIN BAND OF PRECIP. INCREASED POP SATURDAY NIGHT THROUGH SUNDAY...BUT MAINLY IN THE MOUNTAINS FOR NOW. FOR MONDAY...ALL MODELS SHOW A RIDGE OF HIGH PRESSURE ALOFT AMPLIFYING NORTHWARD ALONG THE ROCKIES WITH HIGHS WELL ABOVE NORMAL AND IN THE 50S AND 60S. THE SECOND UPPER LEVEL DISTURBANCE WILL THEN TAKE A SIMILAR TRACK AS THE FIRST ONE...PUSHING ACROSS WYOMING AND COLORADO MONDAY NIGHT AND TUESDAY. THE GFS AND DGEX SHOW THIS SYSTEM STALLING ACROSS THE ROCKIES WITH HIGHER QPF AMOUNTS ALONG AND SOUTH OF I80. KEPT THE HIGHEST POP ACROSS THE SOUTHERN ZONES OF WESTERN NEBRASKA AND SOUTHEAST WYOMING INTO WEDNESDAY MORNING FOR RAIN/SNOW ACROSS THE LOWER ELEVATIONS AND SNOW IN THE MOUNTAINS. TEMPS WILL BE NEAR OR SLIGHTLY ABOVE NORMAL...ALTHOUGH HIGHS WILL BE TRICKY TO FORECAST DUE TO THE TIMING OF INDIVIDUAL COLD FRONTS FOR THE WEEKEND ALONG WITH TUESDAY OF NEXT WEEK. LOW TEMPS WILL BE SEASONABLY COOL AND GENERALLY IN THE TEENS AND 20S. AVIATION...18Z TAF ISSUANCE. VFR CONDITIONS WILL PREVAIL TODAY AS HIGH PRESSURE SETTLES OVER THE AREA. WEST TO NORTHWEST WINDS WILL BE GUSTY AT TIMES THIS AFTERNOON WITH GUSTS UP TO 35 KT POSSIBLE. OTHERWISE...MVFR CIGS UNDER 3K FEET AGL ARE EXPECTED THIS EVENING NEAR KRWL. FIRE WEATHER...WITH RECENT MOISTURE...FIRE WEATHER CONCERNS WILL REMAIN MINIMAL THROUGH THURSDAY. VERY WINDY CONDITIONS WILL OCCUR IN AND NEAR THE MOUNTAINS TONIGHT AND AGAIN TOMORROW NIGHT THROUGH FRIDAY WHICH COULD HELP TO DRY FUELS ESPECIALLY ACROSS THE PLAINS OF WYOMING AND THE NEBRASKA PANHANDLE. A CHANCE FOR RAIN AND SNOW WILL RETURN ON FRIDAY ACROSS THE MOUNTAINS AND NORTHERN DISTRICTS AS A COLD FRONT DROPS SOUTH THROUGH THE AREA. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...HIGH WIND WARNING UNTIL NOON THURSDAY FOR WYZ106-WYZ110. NE...NONE. && SHORT TERM/FIRE WEATHER...RJM LONG TERM/AVIATION...TJT UPDATE...MAJ
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE CHEYENNE WY 238 PM MST WED MAR 9 2011 NEZ002-003-019>021-054-055-095-096-WYZ101>119-102145- DAWES-BOX BUTTE-SCOTTS BLUFF-BANNER-MORRILL-KIMBALL-CHEYENNE- NORTH SIOUX-SOUTH SIOUX-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- 238 PM MST WED MAR 9 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE WESTERN NEBRASKA PANHANDLE...EAST CENTRAL WYOMING...SOUTH CENTRAL WYOMING AND SOUTHEAST WYOMING. .DAY ONE...THIS AFTERNOON AND TONIGHT A HIGH WIND WARNING IS IN EFFECT TONIGHT FOR THE INTERSTATE 80 CORRIDOR NEAR ARLINGTON AND THE INTERSTATE 25 CORRIDOR NEAR BORDEAUX. SOUTHWEST WINDS OF 35 TO 45 MPH WITH GUSTS UP TO 60 MPH ARE LIKELY BEGINNING LATE THIS EVENING AND CONTINUING THROUGH THE NIGHT. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY THE HIGH WIND WARNING WILL CONTINUE THROUGH NOON ON THURSDAY FOR STRONG WINDS NEAR ARLINGTON AND BORDEAUX IN SOUTHEAST WYOMING. A MORE WIDESPREAD HIGH WIND EVENT WILL BEGIN LATE THURSDAY NIGHT AND WILL CONTINUE THROUGH FRIDAY. SUSTAINED WINDS OF 35 TO 50 MPH WITH GUSTS AROUND 60 MPH ARE POSSIBLE ACROSS MUCH OF SOUTHEAST WYOMING...WITH SLIGHTLY LESS WIND SPEEDS ACROSS THE NEBRASKA PANHANDLE. .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
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHEYENNE WY
1105 PM MST WED MAR 09 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1050 PM HIGH SUST WINDS 5 NW ARLINGTON 41.64N 106.29W
03/09/2011 M45 MPH CARBON WY DEPT OF HIGHWAYS
GUSTS TO 56 MPH
&&
GCLAYCOMPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHEYENNE WY
1106 PM MST WED MAR 09 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1045 PM HIGH SUST WINDS 3 NW I-80 EXIT 255 41.75N 106.51W
03/09/2011 M43 MPH CARBON WY DEPT OF HIGHWAYS
GUSTS TO 48 MPH
&&
GCLAYCOMThe national radar mosaic for the moment the first event began.
7 high wind. Local standard time, as filed.
WYDOT sensor at Arlington measured sustained winds in excess of 40 mph with a peak gust of 63 mph at 9/2325 PM.
WYDOT sensor at Bordeaux measured gusts in excess of 58 mph with a peak gust of 60 mph at 10/0210 AM.
RAWS sensor at Esterbrooke measured wind gusts of 58 mph or more through the event with a peak gust of 62 mph at 0152 AM.
WYDOT sensor at Coleman measured sustained winds in excess of 40 mph with a peak gust of 68 mph at 11/0546 MST.
WYDOT sensor at Whitaker measured sustained winds in excess of 40 mph with a peak gust of 71 mph at 11/1030 MST.
WYDOT sensor at Remount Road measured sustained winds in excess of 40 mph with a peak gust of 62 mph at 11/1316 MST.
UP railroad sensor at Egbert recorded sustained winds in excess of 40 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, March 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: 279442, 279439, 281269, 281268, 281367, 281370, 281270.