A strong pressure gradient over the Yellowstone Plateau of northwest Wyoming generated gap flow out of the east slopes of the Absaroka Range. This flow produced high wind in a favored cross-wind area south of Clark along State Highway 120.
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The episode as NWS RIW wrote it up.
A strong pressure gradient over the Yellowstone Plateau of northwest Wyoming generated gap flow out of the east slopes of the Absaroka Range. This flow produced high wind in a favored cross-wind area south of Clark along State Highway 120. West wind gusted in excess of 58 mph for several hours with a peak of 65 mph around 0515MST.
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 Feb 4, 2:43 AM MST, 1 hour 17 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RIVERTON WY 243 AM MST THU FEB 4 2016 .SHORT TERM...TODAY THROUGH SATURDAY NIGHT IMAGERY SHOWS BROAD UPR TROF ACROSS THE ERN 80 PERCENT OF THE CONUS WITH RIDGE ACROSS THE WRN 20 PERCENT. WY IS UNDER NW FLOW WITH MINOR SW NOW PUSHING THRU THE WRN FA. UPSTREAM...SW TROF NOW MOVING THRU WA/OR CA/NV SECONDARY RIDGE AXIS POSITIONED JUST OFFSHORE THE WCST. SFC HAS GENERAL HIGH P WEST OF WY ACROSS THE GREAT BASIN WITH LOWERING P TO THE NORTHEAST WITH A STRENGTHENING P GRAD IN BETWEEN SUPPORTING SOME GUSTY W TO SW WINDS. EARLY TODAY...STRONG GUSTY WINDS AT TIMES OVR PORTIONS OF THE CODY FOOTHILLS AS THERMAL GRAD AND LEE SIDE TROF FORM THE NRN BIG HORN BASIN IN RESPONSE TO DOWNSLOPING. WINDS WILL LIKELY RUN HIGHEST FROM FROM NOW THRU THE FIRST FEW HRS OF THE AFTERNOON AS RELATIVELY STRONG RIDGE TOP STABILITY AND A GOOD OMEGA GRAD FORM...STRENGTHENED BY MOUNTAIN WAVE FORMATION BY AROUND SUN-UP. HIGH WIND WARNING CONTINUES THRU 1400 MST. ADDITIONALLY...GUSTY WEST TO SOUTHWEST WINDS ACROSS THE WIND CORRIDOR HAVE BEEN MIXING WITH MONDAY'S SNOWFALL TO GIVE AREAS OF BLOWING SNOW AND REDUCED VIS...SO FAR CLOSING I80 BETWEEN ROCK SPRINGS AND RAWLINS AS OF 815 PM. A WINTER WEATHER ADVISORY FOR BLOWING SNOW CONTINUES FROM NOW THRU THIS MORNING. IN RESPONSE TO THE RELATIVELY WEAK UPR SW CURRENTLY IMPINGING ON THE WRN FA WILL BRING SOME DEEPER MOISTURE WITH IT.HOWEVER...SNOWFALL RATES SHOULD BE MODEST AT BEST...WITH 24 HR SNOWFALL ACCUMULATION ACROSS THE WRN MOUNTAINS FROM THIS MORNING THRU TONIGHT RANGING FROM 2 TO 6 INCHES...WITH GENERALLY 1 TO 3 INCHES IN THE VALLEYS. AS THE UPR WAVE MOVES ACROSS WY TODAY...LIGHT SNOW WILL TRY TO SPREAD ACROSS THE SRN FA AND E OF THE DIVIDE. BEST LIFT AND LL CONVERGENCE WILL LAY MAINLY OVR THE WIND CORRIDOR REGION OF THE FA...INCLUDING SWEETWATER AND NATRONA COUNTIES. OTHER AREAS/BASINS IN THE LEE OF THE MOUNTAINS SUCH AS THE WIND RIVER AND BIG HORN BASINS WILL ONLY HAVE VERY LOW CHANCES FOR PRECIP/SNOW THRU THE DAY/EVENING THURSDAY AS NO LOW TO MID LVL UPSLOPE FLOW SETS UP WITH THIS SYSTEM AS IT SPEEDS THRU THE REGION. EXPECTING GENERALLY A TRACE TO PERHAPS AN INCH AND A HALF ACROSS THIS AREA FROM THIS AFTERNOON THROUGH FRIDAY MORNING. THE UPR SYSTEM AND ASSOCIATED CLIPPER TYPE FRONT ASSOCIATED WITH THIS SYSTEM WILL MOVE THRU AND OUT OF THE ERN FA BY FRIDAY MORNING WITH CLEARING SKIES AND HIGH P IN CONTROL OF THE FA AND ONLY LINGERING -SHSN/FLURRIES REMAINING ACROSS PORTIONS OF THE W CNTRL/NWRN MOUNTAINS. LATER FRIDAY...UPR LVL NW FLOW RETURNS ALONG WITH GOOD RIDGE TOP STABILITY...A LEESIDE SFC TROF...AND AN INCREASING THERMAL/OMEGA GRAD ACROSS THE CODY FOOTHILLS ONCE AGAIN FRIDAY NIGHT. ALONG WITH RENEWED MOUNTAIN WAVE ACTIVITY EARLY SAT MORNING...ANOTHER CHANCE FOR LOCALLY HIGH WIND WILL BE POSSIBLE.THEN...MUCH AS TODAY...THE FLOW WILL FLATTEN WITH THE APPROACH AND PASSING OF YET ANOTHER UPR SW...BRINGING IN MORE EPAC MOISTURE TO THE WRN FA...WITH LIGHT TO OCCASIONALLY MODERATE SNOWFALL POSSIBLE THRU THE END OF THE PERIOD. .LONG TERM...SUNDAY THROUGH THURSDAY SYNOPSIS...UPPER RIDGE WILL BUILD INTO THE AREA THROUGH THE PERIOD BRINGING DRY AND SPRING-LIKE TEMPERATURES TO MIXED AREAS BY TUESDAY. STEEP INVERSIONS WILL SET UP OVER WESTERN VALLEYS AND THE WIND RIVER BASIN WHERE TEMPERATURES WILL BE COLDER ALONG WITH PATCHY MORNING FOG. DISCUSSION...SOME LIGHT SNOW OR FLURRIES IN NW FLOW MAY LINGER ACROSS THE NORTHERN MTNS AND NORTH CENTRAL WYOMING INTO SUNDAY MORNING ALONG WITH GUSTY NW WINDS ON BACKSIDE OF SATURDAY'S SHORTWAVE. UPPER RIDGE ALONG THE WEST COAST WILL THEN GRADUALLY BUILD INTO THE AREA THROUGH TUESDAY ALONG WITH WARM AIR ADVECTION...WITH H7 TEMPS NEAR 3-5C BY 00Z WEDNESDAY. THE MAIN FORECAST CHALLENGE WILL BE DIFFERING DEGREES OF WARMING TEMPERATURES BETWEEN MOUNTAINS AND SNOW-FREE AREAS ACROSS PORTIONS OF NORTH CENTRAL WYOMING...VERSUS SNOW COVERED WESTERN VALLEYS AS WELL AS EXTENSIVE SNOW COVER ACROSS MUCH OF SOUTHERN WYOMING INTO THE WIND RIVER BASIN AND NATRONA COUNTIES. GUSTY W-SW WINDS WILL PROVIDE BETTER MIXING FROM ROCK SPRINGS TO CASPER THAT WILL EAT AWAY AT THE SNOW-COVER QUICKER THAN MORE PROTECTED WESTERN VALLEYS AND THE WIND RIVER BASIN WITH THESE LATTER AREAS THE SLOWEST TO WARM UP THROUGH THE WEEK. MODEL BLENDS AND MOS NUMBERS WERE MOSTLY MUCH TOO FAST TO WARM UP THESE SNOW-COVERED AREAS AND TEMPERATURES WERE MANUALLY ADJUSTED DOWN 10-15F IN MAINLY THE JACKSON/STAR VALLEYS AND THE LOWER WIND RIVER BASIN. && .AVIATION.../12Z ISSUANCE/ WEST OF THE CONTINENTAL DIVIDE...KBPI/KJAC/KPNA/KRKS SNOW WILL DEVELOP OVER THE WESTERN MOUNTAINS BY 12Z AND CONTINUE THROUGH 09Z FRIDAY. EXPECT MVFR/IFR CONDITIONS AND MOUNTAIN OBSCURATION. FROM KJAC TO KAFO...PERIODS OF SNOW WILL OCCUR TODAY AND TONIGHT WITH MVFR CIGS/VSBYS AND LOCAL IFR CONDITIONS. IN SW WY AFTER 12Z CLOUDS WILL BE LOWERING WITH SCATTERED SNOW DEVELOPING BY 18Z. AFTER 18Z THROUGH 06Z FRI SCATTERED AREAS OF SNOW WILL OCCUR WITH MVFR CIGS/VSBYS. TERMINAL SITES IN SW WY WILL BE IMPACTED AT TIMES. PLEASE SEE INDIVIDUAL TERMINAL FORECASTS FOR MORE DETAILS. EAST OF THE CONTINENTAL DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD. SCATTERED SNOW SHOWERS WILL DEVELOP AFTER 22Z AND CONTINUE TO THROUGH 09Z FRI. SOME MVFR CONDITIONS WILL OCCUR IN PLACES. TERMINAL SITES MAY SEE A SNOW SHOWER WHICH WOULD PRODUCE MVFR CONDITIONS. THE BIGHORN MOUNTAINS WILL SEE SNOW SHOWERS AFTER 18Z THROUGH 12Z FRIDAY WITH MVFR/IFR CONDITIONS AND MOUNTAIN OBSCURATION. && .FIRE WEATHER... FIRE DANGER REMAINS LOW ACROSS THE FORECAST AREA THROUGH THE REST OF THE WORK WEEK WITH SEASONALLY COLD TEMPERATURES...SNOW COVERING MOST SURFACES....AND A NEW WINTER WEATHER SYSTEM ROLLING THROUGH THE FORECAST AREA TODAY THROUGH FRIDAY MORNING WITH ANOTHER ON ITS HEELS SATURDAY. HOWEVER...WINDS WILL BE QUITE GUSTY AT TIMES ON TODAY AND AGAIN FRIDAY NIGHT ACROSS THE USUAL WIND PRONE AREAS. MOST AFTERNOONS ACROSS WYOMING...EXCEPT FOR THE BASINS...SHOULD SEE FAIR TO GOOD SMOKE DISPERSION. && .RIW WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 11 AM MST THIS MORNING FOR WYZ019- 020-022-030. HIGH WIND WARNING UNTIL 2 PM MST THIS AFTERNOON FOR WYZ003. && SHORT TERM...BRAUN LONG TERM...AEM AVIATION...AR FIRE WEATHER...BRAUN
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RIVERTON WY 248 AM MST THU FEB 4 2016 WYZ001>020-022>030-051200- YELLOWSTONE NATIONAL PARK-ABSAROKA MOUNTAINS-CODY FOOTHILLS- NORTH BIG HORN BASIN-SOUTHWEST BIG HORN BASIN- SOUTHEAST BIG HORN BASIN-OWL CREEK AND BRIDGER MOUNTAINS- BIGHORN MOUNTAINS WEST-BIGHORN MOUNTAINS SOUTHEAST- NORTHEAST JOHNSON COUNTY-SOUTHEAST JOHNSON COUNTY- TETON AND GROS VENTRE MOUNTAINS-JACKSON HOLE- WIND RIVER MOUNTAINS WEST-WIND RIVER MOUNTAINS EAST- UPPER WIND RIVER BASIN-WIND RIVER BASIN-LANDER FOOTHILLS- GREEN MOUNTAINS AND RATTLESNAKE RANGE- NATRONA COUNTY LOWER ELEVATIONS-CASPER MOUNTAIN-STAR VALLEY- SALT RIVER AND WYOMING RANGES-UPPER GREEN RIVER BASIN FOOTHILLS- UPPER GREEN RIVER BASIN-SOUTH LINCOLN COUNTY- ROCK SPRINGS AND GREEN RIVER-FLAMING GORGE-EAST SWEETWATER COUNTY- 248 AM MST THU FEB 4 2016 ...HIGH WIND WARNING FOR THE CODY FOOTHILLS THROUGH EARLY THIS AFTERNOON... ...WINTER WEATHER ADVISORY FOR BLOWING SNOW ACROSS PORTIONS OF CENTRAL AND SOUTHERN WYOMING THROUGH THIS MORNING... THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING. .DAY ONE...TODAY AND TONIGHT STRONG WINDS CONTINUE IN THE CODY FOOTHILLS THROUGH EARLY AFTERNOON. PLEASE SEE HIGH WIND WARNING FOR DETAILS. STRONG WINDS WILL CAUSE BLOWING SNOW AND AREAS OF VISIBILITY OF ONE-HALF MILE OR LESS ALONG INTERSTATE 80 EAST OF ROCK SPRINGS...AND ALONG HIGHWAYS 287 AND 220 FROM BEAVER RIM TO CASPER THIS MORNING. PLEASE SEE WINTER WEATHER ADVISORY FOR DETAILS. AREAS OF MODERATE SNOWFALL EXPECTED OVER THE WESTERN MOUNTAINS TODAY THROUGH FRIDAY MORNING. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY FRIDAY...AREAS OF MODERATE SNOWFALL EXPECTED OVER THE WESTERN MOUNTAINS FRIDAY MORNING. STRONG WINDS POSSIBLE IN THE CODY FOOTHILLS LATE FRIDAY NIGHT. SATURDAY...SNOW SHOWERS SPREADING ACROSS NORTHERN WYOMING DURING THE DAY. STRONG WEST TO NORTHWEST WINDS AND AREAS OF BLOWING SNOW POSSIBLE ACROSS PORTIONS OF CENTRAL AND SOUTHERN WYOMING INCLUDING ALONG INTERSTATES 80 AND 90. STRONG WINDS POSSIBLE IN THE CODY FOOTHILLS. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE URGED TO REPORT WIND GUSTS OVER 50 MPH AND SNOWFALL AMOUNTS. THANK YOU.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 223 AM MST THU FEB 4 2016 WYZ001-012-013-023-024-042300- YELLOWSTONE NATIONAL PARK-TETON AND GROS VENTRE MOUNTAINS- JACKSON HOLE-STAR VALLEY-SALT RIVER AND WYOMING RANGES- INCLUDING THE CITIES OF...LAKE...MAMMOTH...OLD FAITHFUL... JACKSON...AFTON...ALPINE...STAR VALLEY RANCH...THAYNE 223 AM MST THU FEB 4 2016 AN UPPER LEVEL DISTURBANCE WILL PUSH INTO WESTERN WYOMING TODAY...BRINGING INCREASING CHANCES FOR LIGHT TO OCCASIONALLY MODERATE SNOWFALL TO THE WESTERN MOUNTAINS AND VALLEYS. EXPECT SNOWFALL ACCUMULATIONS BY FRIDAY MORNING OF 2 TO 6 INCHES IN MOUNTAINS WITH 1 TO 3 INCHES IN THE VALLEYS. SOUTHWEST WINDS OF 15 TO 25 MPH WITH HIGHER GUSTS WILL MIX WITH THE SNOW AT TIMES CAUSING REDUCTIONS IN VISIBILITY TO LESS THAN 2 MILES...SLICK ROADWAYS...AND SOME DRIFTING OF SNOW. JB
The national radar mosaic for the moment the first event began.
1 high wind. Local standard time, as filed.
Several winds gusts over 58 mph were recorded 8 miles SSW of Clark, including a peak gust of 65 mph.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2016Every state in 2016This day in weather historyWarnings in Wyoming, February 2016
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: 610500.