Thunderstorms formed along the eastern foothills of the Wyoming Range in southwest flow aloft ahead of a trough positioned over the Pacific Northwest. A fast-moving wind maximum helped to strengthen one storm which spawned a funnel cloud west of Marbleton.
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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.
Thunderstorms formed along the eastern foothills of the Wyoming Range in southwest flow aloft ahead of a trough positioned over the Pacific Northwest. A fast-moving wind maximum helped to strengthen one storm which spawned a funnel cloud west of Marbleton.
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 Aug 13, 1:53 PM MST, 2 hours 5 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RIVERTON WY 253 PM MDT WED AUG 13 2014 .SHORT TERM...TONIGHT THROUGH THURSDAY THE MID LEVEL CIRCULATION THAT SUPPLIED FAR WESTERN WY WITH BETWEEN TWO TO FOUR TENTHS OF AN INCH OF PRECIP TUE EVENING IS EXITING INTO MONTANA ATTM. LOOKING UPWIND...SOUTH THROUGH WEST...THERE IS CONVECTIVE ACTIVITY OVER IDAHO THAT WILL MORE OR LESS BE SOMEWHAT CONTINUOUS FOR THE NEXT COUPLE OF DAYS UNDERNEATH THE JET MAX THERE. THIS CONVECTIVE ACTIVITY WILL SPILL INTO WESTERN WY DURING THE REST OF THE AFTERNOON AND EVENING WHERE THE BEST INSTABILITY IS MOST IMPRESSIVE WHERE EARLY CLEARING TOOK PLACE BEHIND LAST NIGHTS AFOREMENTIONED H7 EXITING CIRCULATION. WEAKER CONVECTION WILL OCCUR TO THE EAST. THEN TO THE SOUTH...THE MEXICAN CIRCULATION IS NOW OVER FAR NORTHERN ARIZONA AND MOVING NORTH TOWARD WY. AT ITS PRESENT SPEED...THE LEADING EDGE OF THE ASCT SWATH OF PRECIP/MOIST BL SHOULD ARRIVE IN SOUTHWEST WY SHORTLY AFTER SUNSET AND THEN ACROSS THE REST OF SOUTHERN AND EASTERN WY AFTER MIDNIGHT. THE PRECIP ASCT WITH THIS FEATURE WILL LIKELY PLAY OUT AS AN AREA OF WIDESPREAD RAINFALL WITHOUT THUNDER...PRIMARILY AFFECTING AN AREA FROM RKS TO KRIW TO KBYG WITH SWEETWATER COUNTY TO CASPER EXPECTING TO RECEIVE THE MOST RAINFALL FOR A PERIOD OF 6 TO 9 HOURS...ENDING SHORTLY AFTER NOON THU. THIS IS BASED ON THE TIMING OF THE FAVORED ECMWF OVER THE SLIGHTLY FASTER GFS WHICH HAS COME MORE IN LINE WITH THE ECMWF. IN SPITE OF THE VAST DIFFERENCES IN SOLNS WITH THE GFS AND THE ECMWF...THE GFS AND ECMWF ARE NOW FRIENDS. THE ECMWF HAS THE ASCT MID LEVEL CIRCULATION TRACKING ACROSS SOUTHERN WY LATE TONIGHT/THU MORNING AND OVER NORTHEAST WY 06Z FRI WITH THE GFS OVER NE WY AS EARLY AS 00Z FRI INSTEAD OF NEBRASKA AS IN EARLIER RUNS. WENT WITH HIGH POPS AND RELATIVELY UNREMARKABLE RAINFALL TOTALS GIVEN THE PROBABILITY FOR ANY ONE LOCATION TO RECEIVE ONE HALF INCH BEING FAIRLY NEGLIGIBLE ACCORDING TO THE MODELS. HOWEVER...CANT RULE OUT THE POTENTIAL FOR SHORT TERM LOCALLY HEAVY RAINFALL RATES. THEN THE SOUTHWEST DIFLUENT FLOW BEHIND THE BIGGER LOW OVER THE PAC NW WILL QUICKLY PRODUCE MORE CONVECTION/THUNDERSTORMS BEHIND THE CLEARING IN EASTERN WY THURSDAY AFTERNOON...ESPECIALLY IN NORTHWEST WY WHERE SCATTERED TO NUMEROUS ACTIVITY IS EXPECTED WITH STRONGER STORMS EXPECTED TO THE NORTHWEST OF THERE OVER IDAHO/WESTERN MT. HOWEVER...A GOOD CHANCE OF SCATTERED THUNDERSTORMS ARE EXPECTED OVER THE ENTIRE CWA. OVERALL...COOLER TEMPERATURES ARE EXPECTED THU WITH THE ADDED CLOUDS AND PRECIP. WITH DEW POINTS IN THE 50S...EXTENSIVE MULTILAYER CLOUD COVER IS EXPECTED THU SO THE DOMINANT FEATURE WITH ANY T STORMS WILL BE RAINFALL BUT NOT ENOUGH SOLAR INSULATION WILL BE PRESENT FOR STRONG CONVECTION IN OUR CWA. .LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY MEDIUM RANGE MODELS IN FAIRLY GOOD AGREEMENT THROUGH MOST OF THE FORECAST PERIOD AS THE GFS HAS CONTINUED TO COME MORE IN-LINE WITH THE ECMWF. LARGER DIFFERENCES BEGIN TO EMERGE TOWARD THE VERY END OF THE MEDIUM RANGE...BUT OVERALL MODELS WERE CONSISTENT THROUGH NEXT WEDNESDAY. UPPER LOW NOW OVER ARIZONA WILL BE IN THE VICINITY OF THE BLACK HILLS BY EARLY FRIDAY. SHOWERS AND STORMS WILL GRADUALLY DECREASE FROM SOUTHWEST TO NORTHEAST DURING THE EVENING HOURS. BEST CHANCE FOR LATE NIGHT CONVECTION WILL BE ALONG AND EAST OF THE BIGHORNS CLOSER TO THE UPPER LOW. MILD OVERNIGHT LOWS ANTICIPATED EAST OF THE DIVIDE WITH CLOUD COVER...WITH BETTER COOLING EXPECTED OVER THE SOUTHWEST AS CLOUDS DISSIPATE. THIS FIRST UPPER LOW WILL LARGELY BE A NON-PLAYER IN OUR WEATHER FRIDAY AS IT PUSHES EAST INTO SOUTH DAKOTA. HAVE KEPT SCATTERED CONVECTION ACROSS JOHNSON COUNTY IN ASSOCIATION WITH THIS SYSTEM. MEANWHILE...BACK TO OUR WEST...A LARGER UPPER LOW OVER THE COLUMBIA RIVER GORGE THURSDAY NIGHT WILL MAKE SLOW PROGRESS INTO EASTERN WASHINGTON ON FRIDAY. THERE WILL BE ENOUGH MOISTURE AND WEAK UPPER LEVEL JET ENERGY TO SUPPORT CONVECTION ACROSS OUR NORTHWEST MOUNTAINS LATE IN THE DAY. THIS UPPER LOW WILL TRACK TOWARD EXTREME SOUTHERN ALBERTA ON SATURDAY. HAVE CONTINUED THE THINKING OF LOW RAIN CHANCES ACROSS OUR FAR NORTH SATURDAY P.M. OTHERWISE...THE TRACK OF THIS SYSTEM AND DRIER AIRMASS PUSHING IN FROM THE WEST WILL LARGELY MEAN DRY WEATHER FOR THE FORECAST AREA SATURDAY. WEAK SHORTWAVE...WITH LITTLE MOISTURE TO WORK WITH...WILL TRAVERSE THE STATE IN ZONAL FLOW ON SUNDAY. THE NORTHWEST AND NORTHERN MOUNTAINS LOOK TO BE THE LOCATIONS WITH THE BEST OPPORTUNITY FOR CONVECTION SUNDAY. WEST-NORTHWEST FLOW WILL FOLLOW FOR MONDAY AS THIS WEAK WAVE MERGES WITH UPPER LOW WHICH WILL THEN BE OVER NORTH DAKOTA. THERE WILL BE ENOUGH MOISTURE AND INSTABILITY TO GENERATE WEAK DIURNAL CONVECTION ACROSS THE NORTHERN-THIRD OF OUR FORECAST AREA MONDAY AND TUESDAY IN THIS PATTERN. ECMWF ADVERTISES A WELL-TIMED SHORTWAVE TUESDAY AFTERNOON WHICH WOULD CERTAINLY INCREASE CONVECTION. MADE SOME MINOR ADJUSTMENTS FOR THAT AFTERNOON...BUT OBVIOUSLY TOO FAR OUT AT THIS RANGE TO DO MUCH MORE THAN THAT. SOUTHWEST WYOMING...AND PROBABLY MOST CENTRAL AREAS...SHOULD SEE MAINLY DRY CONDITIONS THROUGH THE EARLY WEEK AND EVEN INTO WEDNESDAY. ECMWF HAS BACKED OFF ON COOLER AIR FILTERING IN FROM THE NORTH ON WEDNESDAY. INSTEAD... THE ECMWF DEPICTS THE BEGINNINGS OF A DEEPENING TROUGH ACROSS THE PACIFIC NORTHWEST HEADING INTO THURSDAY. THIS OCCURS AS PACIFIC ENERGY MERGES WITH ENERGY HEADING OUT OF ALASKA AND NORTHWEST CANADA AND PACIFIC RIDGE AMPLIFIES ALONG 150W. 12Z RUN OF THE ECMWF SHOWS THAT A HINT OF FALL WOULD ARRIVE FRI/SAT OF NEXT WEEK. && .AVIATION.../00Z ISSUANCE/ WITH MONSOONAL MOISTURE IN PLACE...WILL RESULT IN CONTINUED SCATTERED CONVECTION IN THE WEST AND SOUTH AND ISOLD TO WDLY SCT CONVECTION DEVELOPING ELSEWHERE THROUGH THIS EVENING. THE MOST NUMEROUS ACTIVITY SHOULD BE OVER THE WEST AND SOUTH...WITH THE LEAST OVER THE NORTH...ESPECIALLY THE EASTERN HALF OF THE BIG HORN BASIN. THE ACTIVITY ACROSS THE WEST IS EXPECTED TO WANE AN HOUR OR TWO AFTER SUNSET. A LOW SYSTEM COMING OUT OF THE DESERT SOUTHWEST WILL BRING A SWATH OF STRATIFORM RAINFALL TO MAINLY AN AREA FROM KRKS TO KRIW TO KBYG INCLUDING KCPR WITH KRKS AND KCPR EXPERIENCING THE MOST PROLONGED PERIOD OF RAINFALL WHICH WILL BEGIN AROUND 04Z IN SOUTHWEST WY INCLUDING KRKS TONIGHT AND ENDING AT KCPR SHORTLY AFTER 18Z THURSDAY. WIDESPREAD MVFR CONDITIONS/MTN OBSCURATIONS ARE EXPECTED WITH THIS EVENT. THEN ANOTHER ROUND OF AFTERNOON THUNDERSTORMS ARE EXPECTED TO OCCUR BEHIND AND TO THE WEST OF THIS THIS EXITING SWATH OF RAINFALL THURSDAY AFTERNOON. && .FIRE WEATHER... MONSOONAL MOISTURE WILL MOVE OVER THE AREA FOR THE NEXT FEW DAYS AND BRING CHANCES OF SHOWERS AND THUNDERSTORMS THROUGH THE REST OF THE WORKWEEK. MONSOONAL MOISTURE WILL BE THE DEEPEST THURSDAY SO MOST AREAS WILL HAVE A CHANCE OF SHOWERS AND THUNDERSTORMS WITH THE LOWEST CHANCE IN THE NORTH CENTRAL PORTION OF THE STATE. EXPECT A DECREASING CHANCE FOR SHOWERS STARTING ON FRIDAY. WINDS ARE EXPECTED TO REMAIN LIGHT TO MODERATE EXCEPT NEAR THUNDERSTORMS. WITH THE MOISTURE EXPECTED...FIRE CONCERNS SHOULD REMAIN MINIMAL INTO FRIDAY. && .RIW WATCHES/WARNINGS/ADVISORIES... NONE. && SHORT TERM...LIPSON LONG TERM...CNJ AVIATION...LIPSON FIRE WEATHER...LIPSON
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RIVERTON WY 500 AM MDT WED AUG 13 2014 WYZ001>020-022>030-141100- 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- 500 AM MDT WED AUG 13 2014 THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING. .DAY ONE...TODAY AND TONIGHT SCATTERED AFTERNOON AND EVENING THUNDERSTORMS. SOME STORMS MAY PRODUCE HEAVY RAIN.. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY THURSDAY...SCATTERED AFTERNOON AND EVENING THUNDERSTORMS. SOME THUNDERSTORMS MAY PRODUCE HEAVY RAIN. FRIDAY...ISOLATED THUNDERSTORMS...ESPECIALLY ACROSS JOHNSON AND NATRONA COUNTIES. SUNDAY...ISOLATED TO WIDELY SCATTERED THUNDERSTORMS ACROSS NORTHERN WYOMING. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE URGED TO REPORT RAINFALL AMOUNTS AND ANY IMPACTS. THANK YOU. TEAM RIVERTON
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 257 PM MDT WED AUG 13 2014 WYZ001-012-013-132230- YELLOWSTONE NATIONAL PARK-TETON AND GROS VENTRE MOUNTAINS- JACKSON HOLE- INCLUDING THE CITIES OF...LAKE...MAMMOTH...OLD FAITHFUL...JACKSON 257 PM MDT WED AUG 13 2014 SCATTERED SHOWERS AND THUNDERSTORMS WILL TRACK NORTHEAST AT 10 TO 15 MPH ACROSS WESTERN TETON COUNTY AND SOUTHWEST YELLOWSTONE NATIONAL PARK THROUGH 430 PM. THIS DOES INCLUDE GRAND TETON NATIONAL PARK...PARTICULARLY THOSE AREAS NORTH OF JENNY LAKE AND SIGNAL MOUNTAIN. BRIEF HEAVY RAINFALL...PEA SIZED HAIL...AND WIND GUSTS TO 35 MPH ARE ALL POSSIBLE WITH THE STRONGER STORMS. IMPACTED LOCATIONS INCLUDE JACKSON LAKE...COLTER BAY...LIZARD CREEK CAMPGROUND...GRASSY LAKE RESERVOIR...AND LEWIS LAKE. BE SURE TO HEAD INDOORS OR INSIDE A VEHICLE IF YOU HEAR THUNDER.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 349 PM MDT WED AUG 13 2014 WYZ024-027-132230- SALT RIVER AND WYOMING RANGES WY-SOUTH LINCOLN COUNTY WY- 349 PM MDT WED AUG 13 2014 ...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL LINCOLN COUNTY UNTIL 430 PM MDT... AT 346 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM AROUND 5 MILES SOUTHEAST OF COKEVILLE...MOVING NORTH AT 20 MPH. HAIL UP TO ONE-HALF INCH IN DIAMETER AND WIND GUSTS UP TO 45 MPH ARE EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAINFALL. THIS STORM WILL BE NEAR... PINE CREEK SKI AREA AROUND 410 PM MDT. IF THREATENING WEATHER APPROACHES YOUR AREA...TAKE SHELTER IN A STURDY BUILDING. REPORT HAZARDOUS WEATHER TO THE NATIONAL WEATHER SERVICE OFFICE IN RIVERTON AT 1-800-211-1448. LAT...LON 4237 11093 4231 11060 4190 11079 4195 11102 TIME...MOT...LOC 2149Z 194DEG 17KT 4202 11087 MURRELL
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 420 PM MDT WED AUG 13 2014 WYZ001-012-013-140030- JACKSON HOLE-TETON AND GROS VENTRE MOUNTAINS- YELLOWSTONE NATIONAL PARK- 420 PM MDT WED AUG 13 2014 SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE TO TRACK NORTHEAST AT 10 TO 15 MPH ACROSS YELLOWSTONE NATIONAL PARK. ADDITIONAL STORMS ARE ANTICIPATED ACROSS THE NORTHERN PORTION OF THE PARK... ESPECIALLY AROUND MAMMOTH...TOWER JUNCTION...AND THE LAMAR VALLEY. BRIEF HEAVY RAINFALL...PEA SIZED HAIL...AND WIND GUSTS TO 35 MPH ARE ALL POSSIBLE WITH THE STRONGER STORMS. RAINFALL AMOUNTS COULD TOTAL ONE-QUARTER TO ONE-HALF INCH. THE SOUTHERN PORTION OF YELLOWSTONE NATIONAL PARK AND MUCH OF TETON COUNTY CAN ALSO EXPECT SHOWERS AND STORMS THROUGH THE EARLY EVENING. BE SURE TO HEAD INDOORS OR INSIDE A VEHICLE IF YOU HEAR THUNDER. MOTORISTS SHOULD ALSO BE PREPARED TO SLOW DOWN TO AVOID THE POSSIBILITY OF HYDROPLANING.
The Riverton/Lander radar (KRIW), 161 km away, was scanning. The volume nearest the first event began at 22:56 UTC.
1 funnel cloud. Local standard time, as filed.
A sheriff's deputy observed and photographed a funnel cloud west of Marbleton around 1600MST.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2014Every state in 2014This day in weather historyWarnings in Wyoming, August 2014
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: 533470.