Strong winds aloft combined with a strong surface pressure gradient produced gusty winds in southeast Wyoming.
Every event with a place to put it; 4 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 strong surface pressure gradient produced gusty winds in 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 Dec 26, 9:42 PM MST, 4 hours 4 minutes earlier.
AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE CHEYENNE WY 942 PM MST SUN DEC 26 2010 .UPDATE...TONIGHT... FORECAST INHERITED FROM THE DAY SHIFT REMAINS IN PRETTY GOOD SHAPE...AND ONLY HAVE MADE MINOR ADJUSTMENTS TO WIND SPEEDS. ALSO MADE SOME MINOR ADJUSTMENTS TO THE MOUNTAIN PRECIPITATION CHANCES FOR TONIGHT BASED ON THE 700 MB FLOW VEERING TO MORE OF A WEST- NORTHWEST DIRECTION TONIGHT AND THE INDICATION FROM THE 00Z SOUNDINGS THAT MOISTURE IN THE MID-LEVELS WILL CONTINUE TO ADVECT INTO THE SOUTHWEST ZONES OVERNIGHT. && .AVIATION...06Z ISSUANCE... BREEZIER CONDITIONS THAN THE PAST FEW NIGHTS WILL HELP TO KEEP VFR CONDITIONS ACROSS THE AREA...WITH NO FOG FORMATION EXPECTED OVERNIGHT. THERE WILL BE A VERY SLIGHT CHANCE FOR SOME MVFR CEILINGS TO DEVELOP NEAR RAWLINS OVERNIGHT...BUT SATELLITE IMAGERY THIS EVENING SHOWS A POSSIBLE BACK EDGE TO THE LOW CLOUDS WEST OF CARBON COUNTY...AND PROBABLY ALONG THE FRONTAL BOUNDARY THAT WILL BEGIN TO MOVE THROUGH THE AREA. THEREFORE WILL ONLY KEEP SOME VICINITY SHOWERS IN THE RAWLINS AREA EARLY IN THE TAF PERIOD. PERIODS OF MOUNTAIN OBSCURATION WILL CONTINUE TO BE POSSIBLE NEAR THE SIERRA MADRE AND SNOWY RANGES WHERE SOME OROGRAPHIC SHOWERS WILL STILL BE POSSIBLE OVERNIGHT. ELSEWHERE...EXPECT VFR CONDITIONS. && .PREV DISCUSSION... /ISSUED 224 PM MST SUN DEC 26 2010/ SHORT TERM...TONIGHT THROUGH TUESDAY... A SHORTWAVE TROUGH WILL MOVE ACROSS THE ROCKIES TONIGHT AND MONDAY MORNING WITH A SPLIT FLOW ALOFT OVER THE REGION. THE FEATURE WAS LOCATED FROM EASTERN IDAHO TO SOUTH CENTRAL UTAH EARLY THIS AFTERNOON. PRECIPITATION AHEAD OF THE SHORTWAVE TROUGH WAS OVER EASTERN IDAHO AND UTAH AS OF 20Z. THE ASSOCIATED SURFACE COLD FRONT APPEARED TO BE OVER WESTERN WYOMING EARLY THIS AFTERNOON. MOISTURE WILL INCREASE OVER THE CWA WITH THE APPROACH OF THE SHORTWAVE TROUGH. CLOUDS WILL LOWER AND INCREASE...BUT IT STILL LOOKS LIKE MOST OF ANY SNOWFALL WILL OCCUR OVER AND NEAR THE SNOWY AND SIERRA MADRE RANGES TONIGHT AND INTO MONDAY MORNING. DUE TO CLOUD TOPS WARMING SOME CURRENTLY UPSTREAM AND QUICK NATURE OF THE STORM SYSTEM HAVE PLACED ABOUT AN INCH OF NEW SNOW IN THOSE MOUNTAINS ESPECIALLY ABOVE 8500 FEET MSL. FAIRLY FAST WEST OR NORTHWEST FLOW ALOFT WILL BE OVER THE REGION THROUGH TUESDAY AFTER THE PASSAGE OF THE SHORTWAVE TROUGH ON MONDAY. THERE WILL BE A BRIEF BREAK IN THE CLOUD COVER ...WITH MID AND HIGH CLOUDS SPREADING BACK OVER THE CWA MONDAY NIGHT AND TUESDAY. COLD AIR ADVECTION BEHIND THE FRONT AND TROUGH WILL BRING COOLER TEMPERATURES TO PARTS OF THE REGION ON MONDAY...ESPECIALLY OVER THE SOUTHEAST WYOMING PLAINS EAST OF THE LARAMIE RANGE. THE MAIN FORECAST CONCERN THROUGH TUESDAY WILL BE THE STRONG WINDS. CURRENTLY...WESTERLY SURFACE WINDS WERE GUSTING BETWEEN 40 AND 50 MPH IN SOME AREAS ALONG AND WEST OF THE LARAMIE RANGE. THE SURFACE PRESSURE GRADIENT HAS TIGHTENED TODAY AS A SURFACE LOW PRESSURE TROUGH HAS DEEPENED OVER FAR EASTERN WYOMING. DURING THAT SAME TIME...SOUTHWEST WINDS HAVE INCREASED TO 40 KNOTS ON THE LOWEST GATE OF THE MEDICINE BOW PROFILER. THE CURRENT WINDS MAY DIMINISH SOME AFTER SUNSET AND THEN INCREASE TONIGHT AND CONTINUE FOR MUCH OF MONDAY AS THE SURFACE COLD FRONT APPROACHES AND PASSES. THE LOW LEVEL HEIGHT DIFFERENCES THROUGH TUESDAY REMAIN FAIRLY LARGE BETWEEN KCAG AND KCPR AND CHANGE FROM MORE AT THE 850 MB LEVEL EARLY TONIGHT TO THE 700 MB LEVEL MONDAY THROUGH TUESDAY. AT THIS TIME WILL KEEP WINDS BELOW HIGH WIND CRITERIA BUT KEEP GUSTS BETWEEN 40 AND 50 MPH ALONG AND WEST OF THE LARAMIE RANGE MONDAY AND TUESDAY. SPEEDS WILL BE LOWER OVER THE PANHANDLE DURING THAT TIME. LONG TERM...TUESDAY NIGHT THROUGH SUNDAY... TUESDAY NIGHT...RELATIVELY MILD NIGHT DUE TO LOW LEVEL MIXING AND DECENT SURFACE PRESSURE GRADIENT. WEDNESDAY...ONE FINAL MILD DAY IN ADVANCE OF THE APPROACHING SHORTWAVE TROUGH AND COLD FRONT. HIGH TEMPERATURES 30S WEST AND 40S EAST WITH 1000-500 MB THICKNESSES NEAR 5460 METERS. OROGRAPHIC SNOW SHOWERS IN THE AFTERNOON ACROSS THE SNOWY RANGE AND SIERRA MADRE RANGE ON MOIST SOUTHWEST FLOW ALOFT. WEDNESDAY NIGHT...PREFRONTAL TROUGH AND COLD FRONT BEGIN TO MOVE EASTWARD ACROSS MUCH OF SOUTHEAST WYOMING WITH CHANCES FOR OROGRAPHIC AND BAROCLINIC BAND SNOW SPREADING ACROSS CONVERSE...CARBON AND MUCH OF ALBANY COUNTIES. THURSDAY...BOTH THE 12Z RUNS OF THE GFS AND ECMWF QUITE SIMILAR IN 500 MB POSITIONING OF CLOSED UPPER LOW ACROSS EASTERN UTAH/WESTERN COLORADO AT 00Z/FRIDAY...LEADING TO MODERATE TO HIGH CONFIDENCE IN THEIR RESPECTIVE SOLUTIONS. EXPECTING SNOW TO BECOME WIDESPREAD DURING THE DAY AS DEEP MOIST AIRMASS IS LIFTED BY DYNAMICS...OROGRAPHICS...UPSLOPE AND WARM AIR ADVECTION LIFT ABOVE THE INITIALLY SHALLOW COLD POOL. BLUSTERY NORTH WINDS WILL OCCUR DUE TO STRONG COLD AIR ADVECTION AS THE SURFACE LOW DEEPENS SIGNIFICANTLY ACROSS EAST CENTRAL COLORADO. BASED ON COMBINATION OF FALLING SNOW AND GUSTY WINDS...BLOWING SNOW LOOKS LIKELY AND HAVE INCREASED SNOW CHANCES TO THE 60 TO 100 PERCENT CATEGORY...DUE TO HIGH CONFIDENCE...IN THE AFTERNOON. WINTER WEATHER HIGHLIGHTS WILL BE NEEDED BY LATER SHIFT TEAMS. THURSDAY NIGHT...SLOW MOVING UPPER LOW PIVOTS NORTHEASTWARD ACROSS NORTHERN AND NORTHEAST COLORADO...PRODUCING MODERATE TO HEAVY SNOW AT TIMES ACROSS EASTERN WYOMING AND WESTERN NEBRASKA EAST OF INTERSTATE 25 ALONG WITH BLUSTERY NORTH WINDS OF 20 TO 35 MPH. 12Z ECMWF AND GFS SIMILAR SYNOPTICALLY LEADING TO MODERATE TO HIGH CONFIDENCE IN MODEL SOLUTIONS. FRIDAY...FORTUNATELY...CLOSED UPPER LOW MOVES PROGRESSIVELY NORTHEAST INTO THE DAKOTAS BY 00Z/SATURDAY WITH SNOW CHANCES DECREASING ACROSS OUR COUNTIES FROM WEST TO EAST...THOUGH IT WILL BE QUITE BLUSTERY AND COLD WITH MAXIMUM TEMPERATURES ONLY IN THE SINGLE DIGITS AND TEENS. SATURDAY...CONTINUED COLD BUT LIKELY DRY AS LOW AND MID LEVEL MOISTURE WANES. SUNDAY...LOW AMPLITUDE SHORTWAVE RIDGING ALOFT PREVAILS...KEEPING IT DRY. AVIATION...00Z TAF ISSUANCE... VFR CONDITIONS ARE EXPECTED THROUGH TUESDAY OVER THE CWA. CLOUDS WILL INCREASE AND LOWER THROUGH 12Z AS A WEAK STORM SYSTEM MOVES ACROSS THE CWA. LIGHT SNOW WILL FALL OVER THE MOUNTAINS BETWEEN 04Z AND 15Z WITH THE SNOWY RANGE OBSCURED DURING THAT TIME. OTHERWISE...BASES WILL LOWER TO AROUND 5 THOUSAND FEET AGL AT KRWL AND KSAA EARLY TONIGHT AND CONTINUE THROUGH 12Z. WESTERLY WINDS WILL GUST AS HIGH AS 45 KNOTS IN AREAS ALONG AND WEST OF THE LARAMIE RANGE TONIGHT AND MONDAY WITH GUSTS AS HIGH AS 35 MPH OVER THE PANHANDLE. FIRE WEATHER... SNOW WILL FALL OVER THE SNOWY RANGE LATE TONIGHT AND MONDAY MORNING. OTHERWISE...THE DISTRICT WILL BE DRY THROUGH TUESDAY. THE TEMPERATURES WILL BE NEAR OR JUST ABOVE NORMAL THROUGH WEDNESDAY. THE MAIN CONCERN WILL BE WESTERLY WINDS GUSTING AS HIGH AS 50 MPH THROUGH TUESDAY IN AREAS ALONG AND WEST OF THE LARAMIE RANGE. FURTHER TO THE EAST...WIND GUSTS WILL BE AS HIGH AS 35 MPH DURING THAT TIME. A STORM SYSTEM WILL AFFECT THE REGION THE LAST HALF OF THIS WEEK...WITH MUCH COLDER TEMPERATURES...SNOW AND WINDY CONDITIONS. THE WINTRY WEATHER WILL MAINLY BE ON THURSDAY AND FRIDAY OVER THE CWA. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && UPDATE/AVIATION...CARPENTER SHORT TERM/FIRE WEATHER...WEILAND LONG TERM...RUBIN
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE CHEYENNE WY 140 PM MST SUN DEC 26 2010 NEZ002-003-019>021-054-055-095-096-WYZ101>119-272045- 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- 140 PM MST SUN DEC 26 2010 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 WEST WINDS OF 20 TO 35 MPH WITH GUSTS TO 45 MPH WILL OCCUR THROUGH THIS EVENING...ALONG AND WEST OF THE LARAMIE RANGE. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY A STRONG STORM SYSTEM WILL BEGIN TO AFFECT CARBON COUNTY AND THE SNOWY RANGE ON WEDNESDAY...SPREADING EAST OVER ALL OF SOUTHEAST WYOMING AND THE WESTERN NEBRASKA PANHANDLE BY THURSDAY AFTERNOON. A POTENT COLD FRONT WILL SWEEP ACROSS WEDNESDAY NIGHT AND EARLY THURSDAY...USHERING IN MUCH COLDER TEMPERATURES...BLUSTERY NORTH WINDS AND WIDESPREAD SNOW...WHICH WILL LIKELY BE MODERATE TO HEAVY AT TIMES ON THURSDAY AND THURSDAY NIGHT...PRIMARILY EAST OF INTERSTATE 25. AREAS OF BLOWING SNOW AND REDUCED VISIBILITIES WILL OCCUR. TRAVEL MAY BECOME HAZARDOUS WEDNESDAY NIGHT THROUGH FRIDAY ALONG WITH POSSIBLE SIGNIFICANT SNOW ACCUMULATIONS...ESPECIALLY EAST OF INTERSTATE 25. .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 RUBIN
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHEYENNE WY 1147 PM MST SUN DEC 26 2010 WYZ106-110-116-117-271200- CENTRAL LARAMIE RANGE AND SOUTHWEST PLATTE COUNTY- NORTH SNOWY RANGE FOOTHILLS-SOUTH LARAMIE RANGE- SOUTH LARAMIE RANGE FOOTHILLS- INCLUDING THE CITIES OF...BORDEAUX...ARLINGTON...ELK MOUNTAIN... VEDAUWOO...BUFORD...PUMPKIN VINE...HORSE CREEK...HARRIMAN... WHITAKER 1147 PM MST SUN DEC 26 2010 ...STRONG AND GUSTY WINDS AND AREAS OF BLOWING SNOW OVERNIGHT... STRONG AND GUSTY WINDS WILL CONTINUE ACROSS THE FAVORED WIND AREAS OVERNIGHT ALONG INTERSTATE 80 NEAR ARLINGTON AND ACROSS THE SUMMIT OF THE LARAMIE RANGE...AND ALONG INTERSTATE 25 BETWEEN CHUGWATER AND WHEATLAND. IN ADDITION...THE WINDS ACROSS THE SUMMIT OF THE LARAMIE RANGE WILL CONTINUE TO CAUSE SNOW ALREADY ON THE GROUND TO BLOW ACROSS ROADWAYS CREATING POTENTIAL FOR SLICK DRIVING CONDITIONS. THOSE TRAVELING THROUGH THESE AREAS SHOULD BE PREPARED FOR SLICK ROADWAYS...AND WIND GUSTS TO AROUND 45 TO 55 MPH OVERNIGHT. CARPENTER
The national radar mosaic for the moment the first event began.
4 high wind. Local standard time, as filed.
WYDOT sensor at Arlington recorded wind gusts in excess of 58 mph between 146 and 731 AM with a peak gust of 66 mph at 501 and 506 AM.
UP railroad sensor at Lynch recorded sustained winds in excess of 40 mph early in the morning.
WYDOT sensor at Bordeaux recorded sustained winds in excess of 40 mph.
WYDOT sensor at Wyo Hill recorded both high gusts and sustained winds, peak gust was 66 mph with sustained winds between 45 to 55 mph.
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, December 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: 266971, 266972, 266973, 266974.