Dew points in the lower to mid 50s and afternoon sunshine combined to rapidly generate thunderstorms across Sweetwater County. One storm briefly spawned a funnel cloud near Creston Junction.
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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.
Dew points in the lower to mid 50s and afternoon sunshine combined to rapidly generate thunderstorms across Sweetwater County. One storm briefly spawned a funnel cloud near Creston Junction.
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 Sep 13, 11:23 AM MST, 1 hour 2 minutes earlier.
AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE RIVERTON WY 1223 PM MDT FRI SEP 13 2013 .PREV DISCUSSION... /ISSUED 933 AM MDT FRI SEP 13 2013/ .UPDATE... GIVEN THE AMOUNT OF RAINFALL OVER THE PAST COUPLE OF DAYS AND THE EXPECTED SLOW MOVING MOISTURE RICH THUNDERSTORMS EXPECTED TODAY...A FLASH FLOOD WATCH HAS BEEN ISSUED FOR MUCH OF CENTRAL AND WESTERN WYOMING INCLUDING THE WIND RIVER MOUNTAINS...GREEN RIVER BASIN...UPPER WIND RIVER BASIN...SOUTHWEST SWEETWATER COUNTY...THE ABSAROKAS...SOUTHEAST FREMONT COUNTY AND NATRONA COUNTY INCLUDING CASPER MOUNTAIN. LOCATIONS PARTICULARLY AT RISK ARE THE WILDFIRE BURN SCARS...URBAN AREAS...STEEP CANYONS PRONE TO MUD SLIDES AND AREAS WITH ALREADY SATURATED SOIL...LIKE LA BARGE. .PREV DISCUSSION... /ISSUED 239 AM MDT FRI SEP 13 2013/ .SHORT TERM...FRIDAY THROUGH SUNDAY NIGHT A COMPLICATED AND MESSY WEATHER PATTERN ACROSS WESTERN AND CENTRAL WYOMING HAS CAUSED MUCH MASHING OF TEETH THIS MORNING. THE RADAR IS MAINLY QUIET AS OF 1 AM ALTHOUGH THERE ARE SOME NOCTURNAL THUNDERSTORMS LINGERING JUST SOUTH OF SWEETWATER COUNTY. SATELLITE IMAGERY SHOWS ANOTHER WAVE OF MOISTURE MOVING NORTHWARD THROUGH COLORADO AND WILL MOVE INTO WYOMING TODAY. THINGS MAY BECOME A BIT MORE CONVECTIVE TODAY WITH FLOW BECOMING MORE SOUTHERLY. THIS SHOULD BRING IN SOMEWHAT WARMER AIR. HOWEVER...A BIG X FACTOR WILL BE HOW MUCH SUN CAN BREAK THROUGH THE CLOUDS. MOS NUMBERS ARE RUNNING ABOUT 10 DEGREES WARMER THAN YESTERDAY BUT IN THE TRANSITION SEASONS THESE CAN BE UNRELIABLE. FOR NOW WE HAVE TEMPERATURES WARMER THAN YESTERDAY BUT COOLER THAN MOS. AS FOR HOW MUCH PRECIPITATION AND WHERE THE HEAVIEST WILL BE...BOTH THE NAM AND GFS HAVE THE BEST QPF OVER THE WESTERN AND EASTERN PORTIONS OF THE COUNTY WARNING AREA WITH LESS ACROSS THE MIDDLE. CONTINUITY REFLECTED THIS REASONABLY WELL SO FEW CHANGES WERE MADE. PRECIPITABLE WATER VALUES ARE STILL RATHER HIGH...OVER AN INCH IN MANY AREAS SO HEAVY RAIN WILL ONCE AGAIN BE POSSIBLE. HOWEVER...PINPOINTING HEAVIER RAIN MAY BE HARDER WITH THE CONVECTIVE NATURE OF THE PRECIPITATION. THEREFORE...WE WILL HOLD OFF WITH ANY FLOOD HIGHLIGHTS BUT THIS WILL HAVE TO BE WATCHED. ONE MORE FLY IN THE OINTMENT IS FOR SOME AREAS OF MORNING FOG ACROSS AREAS WHERE IT RAINED ON THURSDAY...WE ADDED PATCHY FOG TO THOSE LOCATIONS. FEW CHANGES WERE MADE TO SATURDAY AS WELL WITH MODELS CONTINUING TO SHOW A WEAK COLD FRONT DROPPING INTO NORTHERN WYOMING. SOME MODELS...ESPECIALLY THE NAM ARE SHOWING A STEADIER BAND OF RAIN ACROSS NORTHERN WYOMING EAST OF THE DIVIDE FOR SATURDAY AFTERNOON AND EVENING. THIS IS IN ASSOCIATION WITH THE BETTER LIFT FROM THE FRONT AND AMPLE MOISTURE WITH WEAK UPSLOPE FLOW WITH PRECIPITABLE WATER VALUES ABOVE AN INCH IN SOME LOCATIONS. MODELS ALSO SHOW SOME DRIER AIR MAY MAKE A PUSH INTO NORTHWESTERN WYOMING SO POPS WERE REDUCED JUST A BIT. ACTIVITY MAY BEGIN TO WANE A BIT HEADING INTO SUNDAY AS SOME WEAK RIDGING BUILDS ACROSS THE STATE AS THE UPPER LEVEL LOW OPENS A BIT AND BEGINS TO MOVE AWAY. HOWEVER...THERE WILL STILL BE ENOUGH MOISTURE AND INSTABILITY FOR ISOLATED TO SCATTERED CONVECTION. .LONG TERM...MONDAY THROUGH FRIDAY MONDAY LOOKS A LITTLE DRIER OVER THE REGION WITH MAINLY MOUNTAIN SHOWERS OR STORMS. A LEE TROF FORMS MON PM THUS THE BREEZY AREAS WILL OCCUR EAST OF THE DIVIDE. A WEATHER SYSTEM MOVES TOWARD WESTERN WY TUESDAY PM. BREEZY AND WARM AHEAD OF THIS SYSTEM FOR MOST PLACES. ANY SHOWERS/STORMS WOULD BE OVER THE WESTERN MOUNTAINS. THE SYSTEM MOVES THROUGH TUE NIGHT WITH A COLD FRONT PASSAGE. ISOLATED SHOWERS WILL OCCUR MAINLY IN THE MOUNTAINS. WEDNESDAY WILL BE COOLER WITH BREEZY AREAS AND ONLY ISOLATED SHOWERS OR STORMS ACROSS THE NORTHERN MOUNTAINS. THURSDAY LOOKS DRY AND MILDER WITH AFTERNOON BREEZY AREAS. FRIDAY LOOKS MOSTLY DRY AND WARMER WITH BREEZY AREAS IN THE AFTERNOON. VERY ISOLATED SHOWERS/STORMS OVER THE NORTHWEST MOUNTAINS. SEASONAL HIGH TEMPS MON AND TUE...THEN COOLER WED. WARMING HIGHS NEXT THURS AND FRI. .AVIATION.../18Z ISSUANCE/ AN AREA OF LIGHT TO MODERATE RAIN IS SPREADING NORTH BETWEEN KCPR AND KPNA WITH SOME EMBEDDED THUNDERSTORMS BEGINNING TO DEVELOP ALONG THE WIND RIVER RANGE. AREAS OF MVFR/LOCAL IFR CONDITIONS AND ISOLATED THUNDERSTORMS WILL CONTINUE TO SPREAD NORTH. THERE IS SOME CLEARING TAKING PLACE BEHIND THIS INITIAL WAVE...WHICH SHOULD QUICKLY BECOME FILLED IN BY SHOWERS AND THUNDERSTORMS THROUGH THE EVENING HOURS...WITH +RA AND MVFR TO OCCNL LIFR CONDITIONS AND WIDESPREAD MOUNTAIN OBSCURATIONS. ISOLATED TO SCATTERED SHOWERS WILL CONTINUE OVERNIGHT FRIDAY ALONG WITH LOCAL IFR/MVFR CONDITIONS AND OCNL MTN OBSCURATIONS...AFFECTING MAINLY EASTERN TERMINALS AFTER MIDNIGHT. .FIRE WEATHER... THE WEATHER WILL CONTINUE UNSETTLED THROUGH THE WEEKEND. THE THREAT OF HEAVY RAIN AND THUNDERSTORMS IN THE MOUNTAINS WILL CONTINUE THROUGH FRIDAY WITH SCATTERED TO WIDESPREAD SHOWERS AND A FEW THUNDERSTORMS ACROSS THE LOWER ELEVATIONS. THERE WILL BE A CONTINUED CHANCE OF SHOWERS AND A FEW THUNDERSTORMS SATURDAY AND SUNDAY WITH SOME WIDESPREAD UPSLOPE RAIN EAST OF THE DIVIDE LATE SATURDAY INTO SATURDAY NIGHT. A SOMEWHAT DRIER AIRMASS WILL MOVE IN MONDAY INTO TUESDAY BUT WITH INCREASING SOUTHWEST FLOW. && .RIW WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH LATE TONIGHT WYZ019-020-022. FLASH FLOOD WATCH UNTIL MIDNIGHT MDT TONIGHT WYZ002-014>016-018-024>028. && SHORT TERM...HATTINGS LONG TERM...AR AVIATION...ALLEN FIRE WEATHER...HATTINGS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RIVERTON WY 1132 AM MDT FRI SEP 13 2013 WYZ001>020-022>030-140600- 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- 1132 AM MDT FRI SEP 13 2013 THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING. ...FLASH FLOOD WATCH IS IN EFFECT FOR PARTS OF WEST CENTRAL WYOMING THIS AFTERNOON AND EVENING... .DAY ONE...TODAY AND TONIGHT MORE SHOWERS AND THUNDERSTORMS ARE LIKELY TODAY AND TONIGHT WITH VERY HEAVY RAIN AS THE MAIN THREAT. LOCALIZED FLOODING IS POSSIBLE...PARTICULARLY ACROSS AREAS RECEIVING CONTINUOUS RAINFALL. GUSTY WIND CAN ALSO BE EXPECTED NEAR ANY THUNDERSTORMS. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY THE POTENTIAL FOR LOCALLY HEAVY RAIN EXISTS SATURDAY AND SUNDAY AS SHOWERS AND THUNDERSTORMS OCCUR OVER THE REGION. ISOLATED THUNDERSTORMS WILL OCCUR IN THE WESTERN MOUNTAINS MONDAY AND TUESDAY MAINLY DURING THE AFTERNOON AND EVENING. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ENCOURAGED TO REPORT ANY RAPIDLY RISING CREEKS OR STREAMS...AS WELL AS ANY FLOODING...INCLUDING MUDSLIDES. THANK YOU. TEAM RIVERTON
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 1248 PM MDT FRI SEP 13 2013 WYZ024-132000- SALT RIVER AND WYOMING RANGES- 1248 PM MDT FRI SEP 13 2013 THUNDERSTORMS WERE DEVELOPING RAPIDLY OVER THE WYOMING RANGE EARLY THIS AFTERNOON. THESE SLOW MOVING THUNDERSTORMS WILL HAVE THE POTENTIAL TO DROP HEAVY AMOUNTS OF RAIN THIS AFTERNOON. PLEASE STAY ALERT AVOID CAMPING OR STOPPING IN LOW LYING AREAS OR IN CANYON AREAS THIS AFTERNOON AND EVENING. A FLASH FLOOD WATCH IS IN EFFECT FOR THE SALT AND WYOMING RANGES UNTIL MIDNIGHT FRIDAY NIGHT. SKRBAC
The Riverton/Lander radar (KRIW), 159 km away, was scanning. The volume nearest the first event began at 19:26 UTC.
1 funnel cloud. Local standard time, as filed.
A funnel cloud was photographed just north of Interstate 80 milepost 186 near Creston Junction.
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, September 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: 474588.