A tight pressure gradient ahead of a potent cold front dropping south across Wyoming produced strong winds across portions of central Wyoming. Wind gusts from 58 mph to 64 mph were common in a few foothill locations and eastern Sweetwater County.
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 RIW wrote it up.
A tight pressure gradient ahead of a potent cold front dropping south across Wyoming produced strong winds across portions of central Wyoming. Wind gusts from 58 mph to 64 mph were common in a few foothill locations and eastern Sweetwater County.
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 Riverton, WY wrote its last area forecast discussion before the first event at Dec 1, 10:55 AM MST, 4 hours 5 minutes earlier.
AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE RIVERTON WY 1055 AM MST SUN DEC 1 2013 .SHORT TERM...SUNDAY THROUGH TUESDAY NIGHT IN CONTRAST TO MY LAST STRING OF SHIFTS THAT WERE DEAD AS A DOORNAIL...THIS LOOKS TO BE QUITE AN ACTIVE ONE WITH SNOW...WIND AND SOME VERY COLD AIR MOVING INTO THE AREA. TO BETTER SUMMARIZE...WE WILL DIVIDE THE DISCUSSION INTO WEST OF THE DIVIDE AND EAST OF DIVIDE. WEST OF THE DIVIDE...THE STORM WILL ARRIVE THERE FIRST. THE FIRST BATCH OF WARM ADVECTION SNOW MOVED THROUGH THE AREA THIS EVENING WITH A QUICK INCH OF SNOW IN SOME LOCATIONS. HOWEVER...THE RADAR HAS REALLY QUIETED DOWN AT THIS POINT WITH THE NEXT BATCH STILL A WAYS OFF. AS A RESULT...WE HAVE LOWERED POPS AND QPF A BIT THROUGH 11 AM TODAY. THE NEXT BATCH OF STEADIER AND HEAVIER PRECIPITATION ASSOCIATED WITH THE NEXT SHORT WAVE AND AIDED BY THE RIGHT REAR QUAD OF A JET STREAK MOVING BY TO THE NORTH WILL SPREAD SNOW...SOME HEAVY ACROSS THE WEST. WE WILL HOIST A WINTER STORM WARNING FOR THE AREAS PREVIOUSLY UNDER A WATCH STARTING AT 11 AM RATHER THAN 5 AM WITH ONLY LIGHT SNOW EXPECTED BEFORE THAT. THERE COULD BE ANOTHER BRIEF LULL IN THE SNOW LATER THIS EVENING AND TONIGHT WITH THE BEST DYNAMICS MOVING OUT BEFORE PICKING UP AGAIN DURING THE DAY ON MONDAY. WE AGREE WITH THE PREVIOUS SHIFT THAT ANOTHER BURST OF VERY HEAVY SNOW WILL OCCUR LATER MONDAY AFTERNOON AND MONDAY EVENING WITH THE ARCTIC FRONT DROPPING SOUTHWARD ACROSS THE AREA AIDED BY A 125 KNOT JET STREAK MOVING INTO THE AREA. THE PREVIOUS DISCUSSION ALSO MENTIONED THE SNOW MAY TAPER OFF EARLIER AND WE AGREE WITH THAT. THE STEADY SNOW SHOULD SHUT OFF AFTER THE PASSAGE OF THE ARCTIC FRONT SO WE WILL END THE WARNING AT 5 AM ON TUESDAY. WE MADE FEW CHANGES PAST TUESDAY WITH MAINLY LIGHT SNOW SHOWERS CONTINUING THROUGH TUESDAY NIGHT. TEMPERATURES WILL BE VERY COLD AS WELL WITH FALLING TEMPERATURES DURING THE DAY A REAL POSSIBILITY WITH THE STRONG COLD ADVECTION. WITH THIS STORM...SOME FAVORED MOUNTAIN AREAS COULD BE LOOKING AT 2 TO 3 FEET OF NEW SNOW WITH THIS STORM. EAST OF THE DIVIDE...A MORE COMPLEX FORECAST ACROSS THIS AREA. TODAY LOOKS TO BE A DRY DAY WITH THE EXCEPTION OF THE BIGHORN RANGE WHERE SOME SNOW MAY FALL WITH THE PASSAGE OF THE FIRST SHORTWAVE. WITH THE PRESSURE GRADIENT TIGHTENING AND 700 MILLIBAR WINDS INCREASING WINDS WILL INCREASE THROUGH THE DAY ACROSS FAVORED AREAS LIKE THE SOUTHWESTERN WIND CORRIDOR AS WELL AS DOWNWIND OF THE ABSAROKAS. THIS INCLUDED EVERYONES FAVORITE CROSSROAD...CLARK. THE STRONGEST WINDS STILL LOOK TO BE LATE TONIGHT AND TOMORROW MORNING FOR AREAS DOWNWIND OF THE ABSAROKAS...THIS TIME POSSIBLY INCLUDING MORE POPULATED AREAS LIKE CODY. ACROSS THE WIND CORRIDOR THE THREAT OF STRONG WINDS WILL CONTINUE THROUGH THE DAY ON MONDAY...INCLUDING CASPER AS 50 TO 60 KNOT 700 MILLIBAR WINDS MIX TO THE SURFACE. WITH THE STRONG DOWNSLOPING FLOW...EXPECT A MAINLY DRY AND MILD DAY FOR MOST AREAS...ESPECIALLY ACROSS THE SOUTHERN TWO THIRDS OF THIS AREA. SINCE HIGH WINDS WILL HOLD OFF UNTIL TONIGHT...WE WILL CONTINUE THE HIGH WIND WATCH FOR NOW. THE MODELS CONTINUE TO BE IN GOOD AGREEMENT THAT THE ARCTIC FRONT WILL DROP INTO NORTHERN WYOMING TOWARD SUNSET ON MONDAY EVENING AND THEN PLUNGE SOUTHWARD ACROSS THE STATE ON MONDAY NIGHT. THE FRONT WILL LIKELY BE ACCOMPANIED BY A HEAVY BURST OF SNOW AS IT DROPS SOUTHWARD THROUGH THE NIGHT. TUESDAY WILL BE A SLAP IN THE FACE FOR PEOPLE AS TEMPERATURES WILL BE 20 AND IN SOME CASES 30 DEGREES COLDER THAN THE PREVIOUS AFTERNOON. WITH STRONG COLD ADVECTION CONTINUING BEHIND THE FRONT...TEMPERATURES WILL FALL DURING THE DAY. THE SOURCE OF THIS AIR MASS IS FROM SIBERIA WITH CROSS POLAR FLOW SETTING UP ACROSS THE AREA. AS FOR SNOW...THERE IS STILL SOME DISAGREEMENT AS TO SPECIFICS. THERE STILL LOOKS TO BE A BIT OF OVERRUNNING BUT THE MODELS HAVE BACKED OFF ON AMOUNTS A BIT. FOR NOW WE LOWERED AMOUNTS SLIGHTLY BUT WITH LACK OF CONSISTENCY BIG CHANGES WERE NOT MADE. MODELS ALSO DIFFER FOR TUESDAY NIGHT WITH THE GFS AND EUROPEAN SHOWING SOME DECENT SNOW CREEPING BACK INTO MAINLY SOUTHERN WYOMING WITH THE LEFT FRONT QUAD OF A JET STREAK. THE NAM KEEPS THIS FEATURE FURTHER SOUTH AND AS A RESULT THINGS MAINLY DRY. WITH THE UNCERTAINTY...WE LEFT CONTINUITY ALONE. TUESDAY NIGHT LOOKS TO BE BITTERLY COLD WITH LOWS FALLING BELOW ZERO...IN SOME CASES WELL BELOW ZERO BY WEDNESDAY MORNING. .LONG TERM...WEDNESDAY THROUGH SUNDAY THE FRIGID ARCTIC AIRMASS WILL REMAIN ENTRENCHED ACROSS THE AREA THROUGH THIS PERIOD. LONGWAVE TROUGH WILL BE ORIENTED SW-NE ACROSS THE ROCKIES ON WEDNESDAY WITH EMBEDDED LOWS OVER NORTHERN MONTANA AND THE EASTERN GREAT BASIN. H7 LOW NEAR GJT 12Z WEDNESDAY WILL DRIFT EAST ACROSS COLORADO...A TREND THAT IS FURTHER SOUTH THAN EARLIER MODEL RUNS AND WILL PLACE HEAVIEST SNOWFALL SOUTH OF WYOMING. HOWEVER...WIDESPREAD LIGHT TO MODERATE SNOW IS EXPECTED ACROSS THE SOUTH INTO CENTRAL WYOMING WEDNESDAY MORNING WITH THE HIGHEST SNOWFALL RATES ALONG AND SOUTH OF INTERSTATE 80. SNOW WILL GRADUALLY TAPER OFF WEST TO EAST WEDNESDAY AFTERNOON AND EVENING. COLD ARCTIC AIR WILL CONTINUE TO SURGE SOUTH INTO THE AREA WEDNESDAY AND WEDNESDAY NIGHT WITH MOST HIGHS ACROSS THE NORTH FROM NEAR ZERO TO 5 ABOVE...WITH SUB-ZERO READINGS IN THE MOUNTAINS. LOWS WEDNESDAY NIGHT WILL BE MOSTLY FROM 10 TO 20 BELOW ZERO WITH 20 TO 30 BELOW READINGS ACROSS YELLOWSTONE NATIONAL PARK. HIGH AMPLITUDE CROSS-POLAR FLOW WILL RESULT IN NEARLY CONTINUOUS RIVER OF ARCTIC AIR FLOWING SOUTH INTO THE REGION THROUGH SATURDAY. THERE WILL BE A FEW EMBEDDED DISTURBANCES THAT WILL BRING SHOTS OF FLUFF ACROSS THE AREA...MAINLY THE WESTERN MOUNTAINS...FRIDAY AND SATURDAY. FORECAST REFLECTS THE SLOWER MORE AMPLIFIED ECMWF...BRINGING MAIN CLIPPER ACROSS THE AREA FRIDAY NIGHT AND SATURDAY. OTHERWISE...IT LOOKS LIKE WE COULD APPROACH RECORD LOWS AND ESPECIALLY RECORD LOW HIGHS (MOSTLY SET ACROSS MUCH OF THE AREA DURING AN EXTENDED COLD SNAP IN 1972) DURING THE FIRST WEEK OF DECEMBER. THOSE RECORD LOW MAXIMUM TEMPERATURES MOSTLY RANGED FROM ZERO TO 7 BELOW ON DECEMBER 4-5 IN THE CENTRAL BASINS. EXPECT ONLY A SLIGHT MODIFICATION OF TEMPERATURES WITH AN INCREASE IN CLOUDS AND SOME LIGHT SNOW FRIDAY AND SATURDAY. && .AVIATION.../18Z ISSUANCE/ EAST OF THE CONTINENTAL DIVIDE... VFR CONDITIONS WILL OCCUR TODAY AND TONIGHT AT THE TERMINAL SITES. SNOW WILL OCCUR OVER THE ABSAROKA AND WIND RIVER MOUNTAINS TODAY AND TONIGHT WITH MVFR TO IFR CONDITIONS. WINDY CONDITIONS AT THE KCPR TERMINAL SITE DURING MUCH OF THE PERIOD. SOUTHWEST WINDS OF 35 TO 45 MPH ARE LIKELY BETWEEN THE RED DESERT AND THE GREEN MOUNTAINS BEGINNING AROUND 06Z TONIGHT. THESE WINDS WILL EXTEND ALL THE WAY TO KCPR BY 12Z MONDAY. MVFR CONDITIONS DUE TO LIGHT SNOW AND LOWERING CIGS ARE EXPECTED AT KWRL AND KCOD AFTER 22Z MONDAY AFTER A COLD FRONTAL PASSAGE. WEST OF THE CONTINENTAL DIVIDE... SNOW WILL OCCUR OVER MOST OF THE WESTERN MOUNTAINS TODAY AND TONIGHT. MVFR TO IFR CONDITIONS WILL PREVAIL WITH FREQUENT MOUNTAIN OBSCURATION. THE KJAC AND KPNA TERMINAL SITES WILL BE IMPACTED BY MVFR AND IFR CONDITIONS AS WELL WITH THE KJAC SITE EXPERIENCING THE LOWEST CIGS AND VSBY. KBPI WILL ENCOUNTER MVFR CONDITIONS. AT KRKS TERMINAL SITE WIND WILL BE THE MAIN IMPACT TODAY AND TONIGHT AS THE WIND SPEEDS WILL BE ON THE INCREASE. VFR CONDITIONS ARE FORECAST TO PREVAIL AT KRKS TERMINAL SITE. SOUTHWEST WINDS OF 35 TO 45 MPH ARE LIKELY BETWEEN KRKS AND THE RED DESERT AFTER 06Z TONIGHT. && .FIRE WEATHER... MILD AND DRY CONDITIONS ARE EXPECTED EAST OF THE DIVIDE THROUGH MONDAY. VERY STRONG WEST SOUTHWEST WINDS ARE POSSIBLE FROM ROCK SPRINGS TO CASPER AS WELL AS ALONG THE EAST SLOPE OF THE CONTINENTAL DIVIDE AND ADJACENT FOOTHILLS MONDAY. SNOWFALL WILL INCREASE IN THE WESTERN MOUNTAINS TODAY AND CONTINUE THROUGH MONDAY NIGHT WITH SEVERAL INCHES OF SNOW LIKELY. BITTERLY COLD WEATHER WILL FILTER INTO THE AREA MONDAY NIGHT THROUGH TUESDAY NIGHT. && .RIW WATCHES/WARNINGS/ADVISORIES... HIGH WIND WATCH FROM THIS EVENING THROUGH MONDAY AFTERNOON WYZ019-030. WINTER STORM WARNING FROM 11 AM THIS MORNING TO 5 AM MST TUESDAY WYZ001-002-012>014-023>025. HIGH WIND WATCH FROM THIS EVENING THROUGH MONDAY MORNING WYZ003. HIGH WIND WATCH FROM LATE TONIGHT THROUGH MONDAY AFTERNOON WYZ020. && SHORT TERM...HATTINGS LONG TERM...AEM AVIATION...LIPSON FIRE WEATHER...HATTINGS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RIVERTON WY 207 PM MST SUN DEC 1 2013 WYZ001>020-022>030-021200- ABSAROKA MOUNTAINS-BIGHORN MOUNTAINS SOUTHEAST- BIGHORN MOUNTAINS WEST-CASPER MOUNTAIN-CODY FOOTHILLS- EAST SWEETWATER COUNTY-FLAMING GORGE- GREEN MOUNTAINS AND RATTLESNAKE RANGE-JACKSON HOLE-LANDER FOOTHILLS- NATRONA COUNTY LOWER ELEVATIONS-NORTH BIG HORN BASIN- NORTHEAST JOHNSON COUNTY-OWL CREEK AND BRIDGER MOUNTAINS- ROCK SPRINGS AND GREEN RIVER-SALT RIVER AND WYOMING RANGES- SOUTH LINCOLN COUNTY-SOUTHEAST BIG HORN BASIN- SOUTHEAST JOHNSON COUNTY-SOUTHWEST BIG HORN BASIN-STAR VALLEY- TETON AND GROS VENTRE MOUNTAINS-UPPER GREEN RIVER BASIN- UPPER GREEN RIVER BASIN FOOTHILLS-UPPER WIND RIVER BASIN- WIND RIVER BASIN-WIND RIVER MOUNTAINS EAST-WIND RIVER MOUNTAINS WEST- YELLOWSTONE NATIONAL PARK- 207 PM MST SUN DEC 1 2013 ...WINTER STORM WARNING THE WESTERN MOUNTAINS AND FOOTHILLS FROM THROUGH MONDAY NIGHT... ...HIGH WIND WARNING FROM EASTERN SWEETWATER COUNTY THROUGH NATRONA COUNTY LATER TONIGHT THROUGH MONDAY AFTERNOON... ...HIGH WIND WATCH FOR THE CODY FOOTHILLS LATE TONIGHT AND MONDAY MORNING... ...HIGH WIND WATCH FOR THE LANDER FOOTHILLS MONDAY... THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING. .DAY ONE...TODAY AND TONIGHT SNOW WILL INCREASE ACROSS WESTERN WYOMING TODAY AND CONTINUE TONIGHT AND IMPACT TRAVEL. WINDS WILL INCREASE AND BECOME STRONG EAST OF THE ABSAROKAS AND ACROSS EASTERN SWEETWATER COUNTY AND NATRONA COUNTY TONIGHT. PLEASE SEE WINTER WEATHER PRODUCTS AND WARNINGS FOR DETAILS. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY MONDAY...SNOW WILL CONTINUE OVER THE WESTERN WYOMING MOUNTAINS. THIS WILL IMPACT TRAVEL OVER THE MOUNTAIN PASSES IN WESTERN WYOMING. STRONG AND POSSIBLY DAMAGING WINDS ARE POSSIBLE EAST OF THE ABSAROKAS AS WELL AS EASTERN SWEETWATER COUNTY AND NATRONA COUNTY. MONDAY NIGHT THROUGH TUESDAY...AN ARCTIC FRONT WILL SPREAD SNOW SOUTH ACROSS CENTRAL WYOMING MONDAY NIGHT AND ACROSS THE INTERSTATE 80 CORRIDOR TUESDAY. ALSO...EXPECT AREAS OF BLOWING SNOW...LIMITED VISIBILITY AND BITTER COLD WIND CHILL TEMPERATURES. WEDNESDAY...LIGHT SNOW ACROSS CENTRAL WYOMING WITH LIGHT TO MODERATE SNOW ACROSS SOUTHERN WYOMING...TAPERING OFF FROM THE WEST IN THE AFTERNOON AND EVENING. BITTER COLD TEMPERATURES WITH HIGHS FROM NEAR ZERO TO 5 ABOVE...AND LOWS WEDNESDAY NIGHT FROM 10 TO 25 BELOW ZERO. THURSDAY THROUGH SATURDAY...AN ARCTIC AIRMASS WILL REMAIN ENTRENCHED ACROSS THE AREA WITH HIGHS ONLY IN THE SINGLE DIGITS... ABOVE AND BELOW ZERO...AND LOW TEMPERATURES FROM 10 TO 25 DEGREES BELOW ZERO. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE URGED TO REPORT SNOWFALL AMOUNTS AND ANY DAMAGE FROM STRONG WINDS. TEAM RIVERTON
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 207 PM MST SUN DEC 1 2013 WYZ003>011-015>020-022-026>030-021200- BIGHORN MOUNTAINS SOUTHEAST-BIGHORN MOUNTAINS WEST-CASPER MOUNTAIN- CODY FOOTHILLS-EAST SWEETWATER COUNTY-FLAMING GORGE- GREEN MOUNTAINS AND RATTLESNAKE RANGE-LANDER FOOTHILLS- NATRONA COUNTY LOWER ELEVATIONS-NORTH BIG HORN BASIN- NORTHEAST JOHNSON COUNTY-OWL CREEK AND BRIDGER MOUNTAINS- ROCK SPRINGS AND GREEN RIVER-SOUTH LINCOLN COUNTY- SOUTHEAST BIG HORN BASIN-SOUTHEAST JOHNSON COUNTY- SOUTHWEST BIG HORN BASIN-UPPER GREEN RIVER BASIN- UPPER WIND RIVER BASIN-WIND RIVER BASIN-WIND RIVER MOUNTAINS EAST- 207 PM MST SUN DEC 1 2013 ...BITTER COLD AIRMASS WILL SPREAD SOUTH ACROSS THE AREA MONDAY NIGHT AND CONTINUE MUCH OF THE WEEK... THE LOWER ELEVATIONS EAST OF THE DIVIDE WILL REMAIN MAINLY DRY AND MILD THROUGH MONDAY...WITH INCREASING WINDS IN MANY AREAS. THOSE IN HIGH-PROFILE VEHICLES AND LIGHT TRAILERS EASILY BLOWN AROUND BY THE WIND ARE URGED TO AVOID MOUNTAIN PASSES...MUCH OF INTERSTATES 80 AND 25...AS WELL AS HIGHWAY 26 BETWEEN CASPER AND SHOSHONI...AND HIGHWAY 789 BETWEEN MUDDY GAP AND BEAVER RIM TONIGHT AND MONDAY. AN ARCTIC FRONT WILL SPREAD SNOW SOUTH ACROSS CENTRAL WYOMING MONDAY NIGHT AND ACROSS THE INTERSTATE 80 CORRIDOR TUESDAY. SNOW AND STRONG WIND WILL ACCOMPANY THIS FRONT AND THE COMBINATION OF SNOW AND WIND COULD PRODUCE WHITEOUT CONDITIONS AT TIMES. MOST OF THE LOWER ELEVATIONS WILL RECEIVE BETWEEN 2 AND 4 INCHES OF SNOW BETWEEN FROM MONDAY NIGHT THROUGH WEDNESDAY WITH 4 TO 8 INCHES IN THE MOUNTAINS. AN ARCTIC AIRMASS WILL REMAIN ENTRENCHED ACROSS THE AREA THURSDAY THROUGH NEXT WEEKEND WITH HIGHS ONLY IN THE SINGLE DIGITS...ABOVE AND BELOW ZERO...AND LOW TEMPERATURES MOSTLY FROM 10 TO 20 DEGREES BELOW ZERO. MAKE SURE YOUR HOMES AND VEHICLES ARE PROPERLY WINTERIZED IN PREPARATION FOR THIS EXTENDED PERIOD OF FRIGID TEMPERATURES. STAY TUNED FOR FUTURE STATEMENTS AND POSSIBLE ADVISORIES...WATCHES AND WARNINGS AS THIS ANTICIPATED WINTER WEATHER EVENT UNFOLDS. TEAM RIVERTON
The national radar mosaic for the moment the first event began.
4 high wind. Local standard time, as filed.
A wind gust to 63 mph was measured at the Clark West Sensor, DW6841.
The weather sensor at the North Fork of the Popo Agie River recorded several wind gusts past 58 mph including a maximum of 64 mph.
The WYDOT weather sensor at Tipton recorded sustained winds of up to 45 mph with a peak gust of 59 mph at 1105MST.
The weather sensor at Beaver Rim measured gusts to 61 mph over a 2.5 hour period the afternoon of December 2.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2013Every state in 2013This day in weather historyWarnings in Wyoming, December 2013
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: 481188, 479331, 479329, 479330.