A tight pressure and thermal gradient developed over the Absaroka Range and strong gap flow resulted in high winds. The winds were strongest in the wind prone areas of the Cody Foothills, especially around Clark.
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The episode as NWS RIW wrote it up.
A tight pressure and thermal gradient developed over the Absaroka Range and strong gap flow resulted in high winds. The winds were strongest in the wind prone areas of the Cody Foothills, especially around Clark. High winds persisted over portions of three days with repeated wind gusts above 60 mph at a sensor along State Highway 120 south of Clark. This sensor measured a peak gust of 74 mph at 0800MST December 15.
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 14, 2:30 PM MST, 0 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RIVERTON WY 230 PM MST SAT DEC 14 2013 .SHORT TERM...TONIGHT THROUGH SUNDAY WIND WILL BE THE BIG STORY THROUGH THE SHORT TERM ACROSS MUCH OF THE FORECAST AREA. THE GRADIENT WILL CONTINUE TO INCREASE AT THE SURFACE AS LEE SIDE TROUGHING COMBINES WITH A SURFACE HIGH BUILDING INTO SOUTHWEST WYOMING. THERE IS ALSO AN IMPRESSIVE GRADIENT ALOFT AS HEIGHTS FALL TOWARD A DEEPENING LOW OVER THE GREAT LAKES AND RISE OVER THE GREAT BASIN...WITH WYOMING CAUGHT IN THE MIDDLE. THERE IS ALSO SOME JET INTERACTION ALREADY STARTING TO FORCE SOME OF THESE STRONGER WINDS TO THE SURFACE...THIS IS EXPECTED TO CONTINUE OFF AND ON THROUGH MONDAY NIGHT. THE GREATEST IMPACT TONIGHT IS EXPECTED TO BE ALONG THE CODY FOOTHILLS AS THE WINDS ALOFT ALIGN WITH THE ABSAROKA RANGE AND THERE IS ENOUGH FORCING ALOFT TO CAUSE A BREAKING MOUNTAIN WAVE INTO CLARK AND WEST CODY. SOME OF THESE GUSTS ARE EXPECTED TO IMPACT HWY120 BETWEEN MEETEETSE AND THE MONTANA BORDER...LIGHT TRAILERS AND HIGH PROFILE VEHICLES ARE ADVISED TO PLAN AN ALTERNATE ROUTE THIS WEEKEND. VERY GUSTY WINDS ARE ALSO EXPECTED ACROSS THE HIGHER ELEVATIONS AS WELL...ALONG THE ABSAROKAS...WIND RIVERS AND BIGHORNS...THOUGH NO INHABITED AREAS ARE EXPECTED TO MEET WARNING CRITERIA IT WILL NO DOUBT BE MUCH WINDIER THAN NORMAL IN THESE AREAS THROUGH THE SHORT TERM PERIOD. THOSE VENTURING INTO THE BACK COUNTRY ARE ADVISED TO PLAN FOR DIFFICULT TRAVEL...BLOWING SNOW AND WIND CHILL READINGS BELOW ZERO. IT WILL ALSO BE WINDIER THAN NORMAL IN THE UPPER WIND RIVER BASIN AROUND CROWHEART AND DUBOIS...PUSHING AS FAR AS WEST RIVERTON AT TIMES. WINDS WILL ALSO BE ON THE INCREASE IN EASTERN SWEETWATER COUNTY AND AREAS TO THE NORTHEAST INTO NATRONA COUNTY WHERE 25 TO 35 MPH WINDS WILL BE COMMON. GUSTS IN FAVORED AREAS COULD EXCEED 45 MPH AT TIMES THROUGH SUNDAY. THE AFOREMENTIONED SURFACE HIGH WILL ALSO KEEP SOME LOW STRATUS AND FLURRIES AROUND THE SOUTHWEST AT TIMES...WHICH COULD HAVE AN EFFECT ON VISIBILITY ALONG INTERSTATE 80 AND NORTH INTO STAR VALLEY AND JACKSON VALLEY. .LONG TERM...SUNDAY NIGHT THROUGH SATURDAY WEAK ISENTROPIC UPGLIDE IN THE WEST CONTINUES INTO THE EVENING SUNDAY BUT GRADUALLY WEAKENS OVERNIGHT. LEFT SOME SMALL POPS IN THE NW MOUNTAINS SUNDAY NIGHT BUT LOOKS LIKE FLURRIES AT WORST. ON MONDAY...A DRIER ISENTROPIC UPGLIDE CONTINUES AND CONFIDENCE IS NOT VERY HIGH THAT FLURRIES OR LIGHT SNOW IS STILL POSSIBLE BUT BASED ON CONSISTENCY AND THE NEIGHBORING OFFICE...I LEFT IN THE SMALL 15-20 POPS THROUGH MONDAY AFTERNOON BEFORE DRYING IT OUT IN THE SLIGHTLY BUILDING HEIGHTS. EAST OF THE DIVIDE...THE WIND EVENT MAY CONTINUE SUNDAY NIGHT INTO EARLY MONDAY ACROSS THE CODY FOOTHILLS. IVE INCREASED THE WINDS QUITE A BIT IN THE GAP FLOW AREAS AND EVEN IN OTHER AREAS WITH POTENTIAL MOUNTAIN WAVE EVENT. THE RIGHT FRONT QUAD OF THE UPPER JET SUNDAY MAY ALSO PROVIDE SOME SUPPORT SUNDAY NIGHT. THE FROUDE CALCULATION PEAKS AROUND 1 AFTER MIDNIGHT SUNDAY NIGHT AND CONTINUE INTO MONDAY MORNING. UPSTREAM WRF SOUNDING SHOWS A WEAK NEAR MTN TOP INVERSION WHICH ALSO SUPPORTS POTENTIAL MOUNTAIN WAVE SUNDAY NIGHT. OTHERWISE...WINDY IN THE WIND CORRIDOR AND EAST SLOPE OF THE MOUNTAIN RANGES BUT NOT HIGH WINDS. TEMPERATURES WILL OBVIOUSLY BE HELD UP IN THE WINDY AREAS BUT THE TRAPPED BASINS AND VALLEYS WILL DROP OFF. THE ONE TRICKY ISSUE WILL BE LEE SIDE MID AND HIGH CLOUDS EXPECTED SUNDAY NIGHT WHICH WILL LIKELY DROP SOUTH FROM THE ABSAROKAS INTO THE WIND RIVER RANGE AREA WHICH MAY HOLD UP TEMPS SOME IN THE COLD BASIN AREAS INCLUDING THE BIGHORN AND WIND RIVER BASINS. MONDAY NIGHT WILL LIKELY BE COLDER IN THESE CENTRAL ZONES DUE TO LESS CLOUD COVER AND STILL LIGHT WINDS. TEMPERATURES IN THE INVERSION AREAS WILL REMAIN COLD MONDAY WITH STEEP INVERSIONS AND NO SIGNIFICANT SHORTWAVE TO MIX DOWN THE WINDS. STRONG WINDS ALOFT NEARBY BUT IT DOESNT LOOK LIKE THAT WILL BE ENOUGH TO MIX OUT THE CENTRAL OR WESTERN TRAPPED BASINS AND VALLEYS. ON TUESDAY...THERE IS FORECAST TO BE A BETTER GRADIENT BUT ALSO A STEEPER MORNING INVERSION. TOUGH CALL THERE AS WE HAD ONE OF THOSE DAYS EARLIER IN THE WEEK THAT ALLOWED THE BASINS TO BREAK OUT A LITTLE. WILL NOT GO AS WARM AS SOME GUIDANCE BUT WILL ACCOMMODATE A WARMER DAY. THE MEDIUM RANGE IS DOMINATED BY THE DEVELOPING STORM SYSTEM AND CANADIAN/ARCTIC COLD FRONT WHICH BEGINS TO IMPACT THE WEST AND NORTH WEDNESDAY NIGHT AND MOST OR ALL OF THE AREA ON THURSDAY WITH MUCH COLDER TEMPERATURES AND SNOW. STRONG WINDS ARE POSSIBLE AHEAD OF THE SYSTEM TUESDAY NIGHT AND EARLY WEDNESDAY...ESPECIALLY THE FAVORED CODY FOOTHILLS ZONE. SYSTEM LOOKS TO HAVE MORE POTENTIAL THAN AN AVERAGE CANADIAN/ARCTIC SYSTEM AS THE DEVELOPING TROUGH DIGS TO THE WEST AND RIGHT FRONT QUAD OF THE JET POTENTIALLY COMES INTO PLAY. NOT A LONG DURATION EVENT BUT ENOUGH TIME TO LAY DOWN LIGHT TO MODERATE SNOW AMOUNTS...ESPECIALLY EAST OF THE DIVIDE. DRY DAY AHEAD OF THE SYSTEM WEDNESDAY WITH BREEZY TO WINDY AREAS AND A BETTER POTENTIAL OF MORE MIXING. SNOW DEVELOPING IN THE WEST AND NORTH WEDNESDAY NIGHT. SNOW ALL AREAS THURSDAY...ESPECIALLY EAST OF THE DIVIDE AND PROBABLY SW. REASONABLE CHANCE OF CLEARING THURSDAY NIGHT ...ESPECIALLY NORTH HALF...WITH A COLD TO BITTER COLD TEMPERATURES AND A COLD DAY FRIDAY. ANOTHER POTENTIAL SHORTWAVE IN THE DEVELOPING NW FLOW FRIDAY NIGHT OR SATURDAY WITH SNOW CHANCES IN THE MOUNTAINS AND POTENTIALLY LOWER ELEVATIONS DEPENDING ON THE TRACK AND STRENGTH WHICH LOOKS MODERATE RIGHT NOW. STRONG TO HIGH WINDS POSSIBLE AHEAD OF AND WITH THIS WAVE PASSAGE IN THE CODY FOOTHILLS. WILL HAVE HIGH POPS IN FOR THE APPROPRIATE PERIODS TO PREPARE EVERYONE FOR ANOTHER ROUND OF SNOW WEDNESDAY NIGHT AND THURSDAY AND SHARPLY COLDER. && .AVIATION.../00Z ISSUANCE/ WEST OF THE DIVIDE...KJAC-KBPI-KPNA-KRKS ROUTES HIGHER MOUNTAIN OBSCURATIONS WITH -SN AND PREVAILING CIGS AROUND 10KFT MSL THROUGH 06Z SUNDAY AS A MOIST NW FLOW WILL REMAIN OVER THE AREA. BRIEF MVFR CONDITIONS WILL OCCUR AT KJAC-KAFO-KRKS. MOUNTAIN TOP WNW WINDS WILL INCREASE TO 30-40KTS 03Z-12Z SUNDAY WITH AREAS OF LLWS POSSIBLE. WEST WIND WILL ALSO CONTINUE TO INCREASE ALONG THE INTERSTATE 80 CORRIDOR TO 20-30KTS...THROUGH AT LEAST 00Z MONDAY. EAST OF THE DIVIDE...KCOD-KCPR-KLND-KRIW-KWRL ROUTES THE MAIN AVIATION HAZARD WILL BE INCREASING WINDS WITH MOUNTAIN WAVE ACTIVITY EXPECTED FROM 30NE KCOD-VCNTY KDUB THROUGH AT LEAST 00Z MONDAY...ALONG WITH AREAS OF LLWS. WIND GUSTS 50-60KTS WILL BE POSSIBLE IN THIS AREA DUE TO BREAKING MOUNTAIN WAVES. MOUNTAIN WAVE ACTIVITY WILL REMAIN ALOFT ACROSS THE WIND RIVER RANGE AND BIGHORNS...EXPECT TURBULENCE OVER MOST MOUNTAIN RANGES THROUGH THE TAF PERIOD. WINDS WILL ALSO INCREASE THROUGH 03Z SUNDAY ACROSS THE INTERSTATE 80 CORRIDOR AND FROM RKS-CPR WITH SW WINDS 20-30KTS AND GUSTS TO 40KTS CONTINUING THROUGH THE TAF PERIOD AND INTO MONDAY. && .FIRE WEATHER... THE STATE WILL BE ENTERING A WINDY PATTERN THIS AFTERNOON...LASTING THROUGH MONDAY NIGHT. VERY STRONG WIND WILL BE POSSIBLE ACROSS THE NORTHERN HALF OF THE CODY FOOTHILLS TONIGHT...AND WILL REMAIN AT VARIED INTENSITY THROUGH MONDAY NIGHT. A HIGH WIND WARNING IS IN EFFECT FOR THIS AREA. A TIGHTENING PRESSURE GRADIENT ACROSS THE REST OF THE STATE WILL PERMIT WIND TO INCREASE ACROSS MUCH OF THE AREA...ESPECIALLY ON MONDAY. OF PARTICULAR NOTE DURING THIS TIME FRAME WILL BE THE WIND CORRIDOR BETWEEN ROCK SPRINGS AND CASPER...ACROSS THE HIGHER ELEVATIONS AND ALONG THE EASTERN SLOPES OF THE CENTRAL MOUNTAINS. NO SIGNIFICANT PRECIPITATION IS EXPECTED UNTIL THE END OF THE WEEK...PERHAPS AS EARLY AS THURSDAY MORNING ACROSS TETON DISPATCH AND THEN INTO THE OTHER DISPATCH AREAS BY THURSDAY NIGHT. && .RIW WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING FROM 8 PM THIS EVENING TO 6 PM MST SUNDAY WYZ003. && SHORT TERM...ALLEN LONG TERM...SKRBAC AVIATION...ALLEN FIRE WEATHER...ALLEN
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RIVERTON WY 1129 AM MST SAT DEC 14 2013 WYZ001>020-022>030-151300- 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- 1129 AM MST SAT DEC 14 2013 ...HIGH WIND WARNING FOR THE CODY FOOTHILLS LATE THIS EVENING INTO SUNDAY EVENING... THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING. .DAY ONE...TODAY AND TONIGHT VERY STRONG WIND WILL DEVELOP ACROSS THE NORTHERN THIRD OF THE ABSAROKA MOUNTAINS AND CODY FOOTHILLS BEGINNING LATE THIS AFTERNOON...AND LASTING THROUGH SUNDAY. PLEASE SEE THE HIGH WIND WARNING FOR MORE DETAILS. ADDITIONALLY...STRONG WIND WILL BE POSSIBLE ACROSS PORTIONS OF THE WIND RIVER BASIN TONIGHT. THE MOST LIKELY IMPACTED AREA WILL BE BETWEEN DUBOIS AND RIVERTON WHERE GUSTS TO 50 MPH WILL BE POSSIBLE. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY SUNDAY...VERY STRONG WINDS POSSIBLY CONTINUING THROUGH THE MORNING HOURS ACROSS THE ABSAROKA MOUNTAINS AND CODY FOOTHILLS. SUNDAY NIGHT AND MONDAY MORNING...ANOTHER ROUND OF STRONG WINDS POSSIBLE ACROSS THE ABSAROKA MOUNTAINS AND CODY FOOTHILLS. THURSDAY...A STORM SYSTEM WILL BRING IN COLDER WEATHER AND POTENTIALLY LIGHT TO MODERATE AMOUNTS OF SNOWFALL. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ENCOURAGED TO REPORT WIND SPEEDS GREATER THAN 45 MPH... OR ANY WIND DAMAGE. THANK YOU. TEAM RIVERTON
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 1145 AM MST SAT DEC 14 2013 WYZ002-008-009-014>016-151300- ABSAROKA MOUNTAINS-BIGHORN MOUNTAINS SOUTHEAST- BIGHORN MOUNTAINS WEST-UPPER WIND RIVER BASIN- WIND RIVER MOUNTAINS EAST-WIND RIVER MOUNTAINS WEST- 1145 AM MST SAT DEC 14 2013 ...LOCALLY STRONG WINDS EXPECTED THIS EVENING THROUGH MONDAY... GUSTY WINDS WILL DEVELOP ACROSS THE AREA THIS EVENING. SOME GUSTS AT THE SUMMITS MAY EXCEED 70 MPH. THOSE WHO PLAN ON VENTURING OUT INTO THE BACK COUNTRY SHOULD PREPARE FOR VERY DIFFICULT TRAVEL AND WIND CHILLS BELOW ZERO...IN ADDITION TO LOW VISIBILITY IN BLOWING SNOW THROUGH MONDAY. WINDS WILL ALSO BECOME GUSTY BETWEEN DUBOIS AND KINNEAR... ESPECIALLY NORTH OF CROWHEART. EXPECT SUSTAINED WINDS OVER 35 MPH AND GUSTS TO 50 MPH AT TIMES BETWEEN MIDNIGHT TONIGHT AND MONDAY NIGHT. 19
The national radar mosaic for the moment the first event began.
1 high wind. Local standard time, as filed.
There were many wind gusts past 58 mph near Clark. The maximum gusts was 74 mph 8 miles south-southwest of Clark.
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: 481259.