Scattered thunderstorms in a dry environment created strong outflow winds well away from the storms.
Every event with a place to put it. 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.
Scattered thunderstorms in a dry environment created strong outflow winds well away from the storms.
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 Jun 30, 2:09 PM MST, 23 hours 6 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RIVERTON WY 309 PM MDT WED JUN 30 2010 .SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT UPPER LEVEL PACIFIC TROUGH EXTENDS SOUTH FROM LOW OVER SOUTHERN BRITISH COLUMBIA...ALONG THE WEST COAST TO WEST CENTRAL CALIFORNIA. THE TROUGH WILL CONTINUE TO MOVE EAST WITH INCREASING SOUTHWEST FLOW ACROSS WESTERN AND CENTRAL WYOMING. SUBTROPICAL MOISTURE FROM ARIZONA AND NEW MEXICO IS BEING ENTRAINED IN THE FLOW AHEAD OF THE PACIFIC TROUGH AND COMBINING WITH MID AND UPPER LEVEL PACIFIC MOISTURE MOVING IN WITH THE TROUGH. WITH STRONG AFTERNOON HEATING...AND AVAILABLE MOISTURE...COMBINING WITH UPPER LEVEL JET DYNAMICS...THUNDERSTORMS HAVE DEVELOP OVER THE WESTERN MOUNTAINS AND HAVE BEEN SPREADING NORTHEAST ACROSS THE BASINS AND VALLEYS. ALSO WEAKER CONVECTION HAS FIRED OFF OF THE BIGHORN MOUNTAINS AND SPREAD ACROSS NORTHERN JOHNSON COUNTY. STRONG WIND GUSTS AND HEAVY RAIN ARE THE MAIN THREATS WITH POSSIBLE SMALL HAIL. THE THUNDERSTORMS ARE EXPECTED TO CONTINUE THROUGH THE EVENING AND TAPER OFF SOME BY MIDNIGHT WITH LINGERING SHOWERS AND ISOLATED THUNDERSTORMS AFTER MIDNIGHT INTO THE EARLY MORNING HOURS THURSDAY. CLOUD COVER WILL MODERATE LOW TEMPERATURES TONIGHT...EXCEPT IN AREAS THAT RECEIVE HEAVY RAIN...WHERE ENHANCED COOLING IS LIKELY DUE TO EVAPORATION AND TRANSPORT OF COLDER AIR ALOFT TO THE SURFACE IN DOWN DRAFTS. CLOUD COVER WILL KEEP HIGHS A BIT LOWER ON THURSDAY AND EVEN MORE ON FRIDAY AS THE TROUGH APPROACHES. WINDS WILL BECOME BREEZY ON THURSDAY AND THEN INCREASE TO WINDY ON FRIDAY. SOME DRY SLOTTING MAY OCCUR BOTH DAYS BRINGING MINIMA OF CONVECTION FROM SOUTHWEST INTO CENTRAL WYOMING WITH ENHANCED AREAS OF CONVECTION IN THE WEST AND EAST. THIS WILL COMPLICATE THE TEMPERATURE AND PRECIPITATION FORECAST THROUGH THE SHORT TERM. MORE COOLING IS EXPECTED FRIDAY NIGHT AS THE TROUGH BEGINS TO MOVE THROUGH WESTERN AND CENTRAL WYOMING. THE BEST DYNAMICS FOR THUNDERSTORMS WILL OCCUR FRIDAY AFTERNOON AND EVENING. .LONG TERM...SATURDAY THROUGH WEDNESDAY MEDIUM RANGE MODELS ARE SHOWING A TROUGH OVER THE INTERMOUNTAIN WEST LIFTING NORTHEAST ACROSS THE NORTHERN ROCKIES SATURDAY/SATURDAY NIGHT. THIS TROUGH WILL INCREASE CHANCES FOR CONVECTION...ESPECIALLY OVER THE NORTHWEST AND JOHNSON COUNTY. THE 00Z ECMWF HAS SOME SECONDARY ENERGY BEHIND THE MAIN TROUGH AFFECTING THE AREA SUNDAY/SUNDAY NIGHT...WHILE THE GEM...GFS AND UKMET ARE MUCH FLATTER AND DRIER...WITH THE MAIN STORM TRACK LIFTING NORTH TO THE U.S./CANADA BORDER. HAVE GONE DRIER FOR NOW FOR SUNDAY/SUNDAY NIGHT. WEAK RIDGING SHOULD DEVELOP EARLY NEXT WEEK...BUT WEAK DISTURBANCES IN THE LIGHT FLOW...COMBINED WITH PEAK HEATING AND A SLIGHTLY UNSTABLE ATMOSPHERE COULD RESULT IN MAINLY AFTERNOON AND EVENING ISOLATED CONVECTION MONDAY THROUGH WEDNESDAY. TEMPERATURES ARE EXPECTED TO BE BELOW AVERAGE SATURDAY AND SUNDAY IN WAKE OF A COLD FRONT FRIDAY NIGHT/SATURDAY. TEMPERATURES SHOULD RETURN TO NEAR SEASONAL LEVELS EARLY NEXT WEEK. && .AVIATION... ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL WIND DOWN THIS EVENING WITH ISOLATED ACTIVITY OVERNIGHT AND THURSDAY MORNING. THE SHOWERS AND THUNDERSTORMS WILL INCREASE IN COVERAGE THURSDAY AFTERNOON. GUSTY OUTFLOWS TO 50KTS ARE POSSIBLE...WITH GREATER WINDS NOT OUT OF THE QUESTION. OCCASIONAL TO FREQUENT LIGHTNING WILL ALSO OCCUR WITH THE THUNDERSTORMS. OTHERWISE SOUTHWEST WINDS WILL WIND DOWN THIS EVENING...PICKING UP AGAIN TOMORROW MORNING AND AFTERNOON. && .FIRE WEATHER... VERY WARM TO HOT CONDITIONS WITH SCATTERED LATE-DAY THUNDERSTORMS ...MOST NUMEROUS OVER THE MOUNTAINS...WILL DEVELOP EACH DAY THROUGH FRIDAY...INITIALLY FORMING OVER THE MOUNTAINS DURING THE EARLY AFTERNOON...THEN MOVING OUT INTO THE VALLEYS AND BASINS DURING THE LATE AFTERNOON/EARLY EVENING HOURS. MODERATE SOUTHWEST WIND AND THURSDAY WILL BECOME STRONG ON FRIDAY....ESPECIALLY FROM ROCK SPRING TO CASPER...AS A PACIFIC TROUGH APPROACHES. THE TROUGH AND ASSOCIATED SURFACE COLD FRONT WILL MOVE THROUGH THROUGH THE DISTRICT SATURDAY...WITH DRY...COOLER EXPECTED SUNDAY. && .RIW WATCHES/WARNINGS/ADVISORIES... NONE. && SHORT TERM...C.BAKER LONG TERM...WM AVIATION...TWB FIRE WEATHER...C.BAKER
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 1216 PM MDT THU JUL 1 2010 WYZ019-026-028-011900- GREEN MOUNTAINS AND RATTLESNAKE RANGE WY-ROCK SPRINGS AND GREEN RIVER WY-UPPER GREEN RIVER BASIN WY- 1216 PM MDT THU JUL 1 2010 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN SWEETWATER AND SOUTHEASTERN SUBLETTE COUNTIES UNTIL 100 PM MDT... AT 1212 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM NEAR STATE HWY 28 MILE MARKER 110...OR 18 MILES SOUTHWEST OF FARSON...MOVING NORTHEAST AT 35 MPH. HAIL UP TO ONE-HALF INCH IN DIAMETER AND WIND GUSTS UP TO 40 MPH ARE EXPECTED WITH THIS STORM...ALONG WITH FREQUENT DANGEROUS LIGHTNING. THIS STORM WILL BE NEAR... STATE HWY 28 MILE MARKER 120 AROUND 1230 PM MDT. U.S. HWY 191 MILE MARKER 30 AROUND 1235 PM MDT. EDEN AND U.S. HWY 191 MILE MARKER 40 AROUND 1240 PM MDT. FARSON AROUND 1245 PM MDT. STATE HWY 28 MILE MARKER 10 AROUND 1255 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 4241 10951 4198 10893 4180 10963 4194 10979 TIME...MOT...LOC 1816Z 230DEG 29KT 4193 10961 BRANHAM
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 101 PM MDT THU JUL 1 2010 WYZ014-015-019-026-028-030-011945- EAST SWEETWATER COUNTY WY-GREEN MOUNTAINS AND RATTLESNAKE RANGE WY-ROCK SPRINGS AND GREEN RIVER WY-UPPER GREEN RIVER BASIN WY-WIND RIVER MOUNTAINS EAST WY-WIND RIVER MOUNTAINS WEST WY- 101 PM MDT THU JUL 1 2010 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN SWEETWATER... SOUTHEASTERN SUBLETTE AND SOUTHERN FREMONT COUNTIES UNTIL 145 PM MDT... AT 1254 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM NEAR STATE HWY 28 MILE MARKER 10...OR 9 MILES NORTHEAST OF FARSON...MOVING NORTHEAST AT 25 MPH. WIND GUSTS UP TO 50 MPH ARE EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN AND FREQUENT DANGEROUS LIGHTNING. THIS STORM WILL BE NEAR... STATE HWY 28 MILE MARKER 20 AROUND 120 PM MDT. STATE HWY 28 MILE MARKER 30 AROUND 140 PM MDT. SOUTH PASS REST AREA AROUND 145 PM MDT. IF THREATENING WEATHER APPROACHES YOUR AREA...TAKE SHELTER IN A STURDY BUILDING. TORRENTIAL RAIN...WHICH MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND UNDERPASSES...IS ALSO LIKELY. DO NOT DRIVE YOUR VEHICLE ON A FLOODED ROADWAY. REPORT HAZARDOUS WEATHER TO THE NATIONAL WEATHER SERVICE OFFICE IN RIVERTON AT 1-800-211-1448. LAT...LON 4267 10891 4194 10853 4194 10927 4226 10943 TIME...MOT...LOC 1901Z 242DEG 22KT 4222 10926 BRANHAM
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 119 PM MDT THU JUL 1 2010 WYZ007-017-012000- OWL CREEK AND BRIDGER MOUNTAINS WY-WIND RIVER BASIN WY- 119 PM MDT THU JUL 1 2010 ...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL FREMONT COUNTY UNTIL 200 PM MDT... AT 112 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM NEAR PILOT BUTTE RESERVOIR...OR 16 MILES NORTHEAST OF FORT WASHAKIE...MOVING NORTHEAST AT 20 MPH. HAIL UP TO ONE-HALF INCH IN DIAMETER AND WIND GUSTS UP TO 40 MPH ARE EXPECTED WITH THIS STORM...ALONG WITH FREQUENT DANGEROUS LIGHTNING. THIS STORM WILL BE NEAR... PAVILLION...STATE HWY 134 MILE MARKER 20 AND OCEAN LAKE AROUND 125 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 4348 10870 4334 10807 4308 10872 4323 10887 TIME...MOT...LOC 1919Z 234DEG 19KT 4321 10869 BRANHAM
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 213 PM MDT THU JUL 1 2010 WYZ005>008-017-012100- BIGHORN MOUNTAINS WEST WY-OWL CREEK AND BRIDGER MOUNTAINS WY-SOUTHEAST BIG HORN BASIN WY-SOUTHWEST BIG HORN BASIN WY-WIND RIVER BASIN WY- 213 PM MDT THU JUL 1 2010 ...SIGNIFICANT WEATHER ADVISORY FOR EXTREME NORTHWESTERN NATRONA... SOUTHERN WASHAKIE...EASTERN FREMONT AND EASTERN HOT SPRINGS COUNTIES UNTIL 300 PM MDT... AT 206 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 5 MILES NORTHWEST OF SHOSHONI...MOVING NORTHEAST AT 45 MPH. HAIL UP TO ONE-HALF INCH IN DIAMETER AND WIND GUSTS UP TO 50 MPH ARE EXPECTED WITH THIS STORM...ALONG WITH FREQUENT DANGEROUS LIGHTNING. THIS STORM WILL BE NEAR... BUFFALO CREEK RD AND KIRBY CREEK RD AROUND 235 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 4399 10861 4377 10714 4317 10792 4334 10845 TIME...MOT...LOC 2013Z 228DEG 40KT 4335 10810 BRANHAM
The Riverton/Lander radar (KRIW), 34 km away, was scanning. The volume nearest the first event began at 20:17 UTC.
2 thunderstorm wind. Local standard time, as filed.
A thunderstorm outflow produced a peak wind gust of 64 mph that was measured by the ASOS at Hunt Field in Lander.
Outflow wind of 66 mph was measured along Interstate 25 north of Kaycee.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2010Every state in 2010This day in weather historyWarnings in Wyoming, July 2010
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: 241660, 241760.