Thunderstorms moving down the Wind River Valley produced strong winds northwest of Morton and near Riverton.
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.
Thunderstorms moving down the Wind River Valley produced strong winds northwest of Morton and near Riverton.
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, 2:34 PM MST, 4 hours 11 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RIVERTON WY 334 PM MDT TUE JUN 30 2009 .SHORT TERM...TONIGHT THROUGH FRIDAY ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE INTO THE EVENING HOURS. SHOWERS TODAY HAVE BEEN PULSE-DRIVEN WITH PERIODS OF SMALL HAIL AND GUSTY WIND. THIS ENVIRONMENT WILL CONTINUE THIS EVENING...ALLOWING ADDITIONAL STORMS TO EXPERIENCE SIMILAR THREATS. SHOWER COVERAGE WILL WEAKEN DURING THE OVERNIGHT HOURS WITH THE LOSS OF DAYTIME HEATING. ANOTHER WAVE OVER THE DESERT SOUTHWEST WILL MOVE NORTHEASTWARD TONIGHT...AND WILL MOVE INTO SOUTHWESTERN WYOMING BY WEDNESDAY MORNING BRINGING ISOLATED SHOWERS AND THUNDERSTORMS. MOVEMENT OF THIS WAVE ALONG WITH THE PASSAGE OF A WEAK JET STREAK AND ITS ASSOCIATED DYNAMICS...WILL CONTINUE THROUGH THE AREA. THIS WILL BRING INCREASED WIND AND SCATTERED SHOWER AND THUNDERSTORM COVERAGE WEDNESDAY...ESPECIALLY ACROSS NATRONA AND JOHNSON COUNTIES. SOME STORMS MAY INCLUDE THREATS OF GUSTY WIND AND SMALL HAIL. THESE UPSWINGS IN AFTERNOON MOISTURE AND DYNAMICS WILL RESULT IN ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS INTO THURSDAY AND FRIDAY. MOST SHOWERS WILL WEAKEN AFTER MIDNIGHT EACH NIGHT WITH ACTIVITY DEVELOPING AGAIN DURING THE AFTERNOON AND EVENING. TEMPERATURES WILL COOL SLIGHTLY FOR WEDNESDAY WITH THESE SLIGHTLY COOLER TEMPERATURES CONTINUE THROUGH THE NEXT COUPLE DAYS. BASIN LOCATIONS EAST OF THE DIVIDE WILL SEE TEMPERATURES IN THE MID TO HIGH 80S...WITH AREAS WEST OF THE DIVIDE SEEING VALUES IN THE 70S. .LONG TERM...FRIDAY NIGHT THROUGH TUESDAY HARD TO PINPOINT ALL THE DETAILS THIS FAR OUT BUT IT DOES APPEAR THAT THERE WILL SEVERAL ACTIVE THUNDERSTORM DAYS BETWEEN FRIDAY AND SUNDAY. MONSOONAL MOISTURE WILL INTERACT WITH SEVERAL SHORTWAVES IN THE WEST TO NORTHWEST FLOW AND SURGES OF WWD MOVING LOW LEVEL. MOISTURE EAST OF THE DIVIDE WILL LIKELY PRODUCE AT LEAST A COUPLE ACTIVE DAYS IN THIS THREE DAY PERIOD. HAVE HIT THE WEEKEND WITH CHANCE POPS IN A BIG PORTION OF THE AREA EAST OF THE DIVIDE INCLUDING MORE OF THE WHOLE NORTH ON SUNDAY. EVEN FRIDAY MAY HAVE TO BE HIT WITH HIGHER POPS ON THE NEXT SHIFT. DRIER SW FLOW MAY DEVELOP EARLY NEXT WEEK IN ADVANCE OF A LARGE PACNW TROUGH. DETAILS STILL IN QUESTION AS NEARBY JET DYNAMICS AND FRONTAL BOUNDARY COULD PRODUCE STRONG TO SEVERE STORMS IN OUR WEST OR NW WITH JUST A SLIGHT SHIFT IN THE CURRENT MODEL FORECAST. THE GFS SHOWS A MUCH STRONGER TROUGH IN THE PACNW THAN THE EURO PLUS THE EURO KICKS THE FIRST LOW OUT TUESDAY ALREADY. LATER SHIFTS CAN EXAMINE FUTURE TRENDS AND ADJUST THE CURRENT FORECAST AS NECESSARY. TEMPERATURES WILL LIKELY BE AT OR BELOW NORMAL EAST OF THE DIVIDE AS SERIES OF FRONTAL BOUNDARIES AND NW FLOW PRODUCE H7 TEMPS AT OR BELOW 10C OVER THE WEEKEND PER CURRENT GUIDANCE. TEMPS WARM CONSIDERABLY EARLY NEXT WEEK IN SW FLOW AS H7 TEMPS SOAR IN THE 12-15C RANGE. && .AVIATION... VFR AND LIGHT WINDS WILL BE COMMON THROUGH TONIGHT. A DISTURBANCE ALOFT WILL COMBINE WITH A SURFACE BOUNDARY ACROSS WYOMING ON WEDNESDAY. THIS WILL RESULT IN SCATTERED SHOWERS AND THUNDERSTORMS OVER WESTERN WYOMING BY AFTERNOON...THEN MOVE INTO NORTHERN AND EASTERN WYOMING BY LATE AFTERNOON. WIND SPEEDS NEAR THE STORMS WILL BE HIGH WITH SOME SURFACE WINDS GUSTING TO NEAR 50 MPH. BRIEF MVFR/IFR CONDITIONS ARE ONLY EXPECTED NEAR CONVECTION DUE TO THE STRONG WINDS AND HEAVY RAIN. WEDNESDAY SHOULD BE THE MOST ACTIVE WEATHER DAY THIS WEEK...AS HIGH PRESSURE ALOFT BUILDS BACK OVER THE REGION WEDNESDAY NIGHT AND THURSDAY. && .FIRE WEATHER... A SERIES OF UPPER LEVEL DISTURBANCES WILL KEEP ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS OVER THE FORECAST AREA FOR THE NEXT FEW DAYS. SHOWER ACTIVITY WILL MOSTLY OCCUR DURING THE AFTERNOON AND EVENING HOURS...THOUGH ISOLATED ACTIVITY WILL STILL BE FOUND OVER THE OVERNIGHT AND MORNING HOURS. THUNDERSTORM ACTIVITY WILL CONTAIN THREATS OF GUSTY WIND AND SMALL HAIL...ALONG WITH PERIODS OF HEAVY RAIN. TEMPERATURES WILL COOL ON WEDNESDAY...WITH THESE SLIGHTLY COOLER TEMPERATURES CONTINUING THROUGH FRIDAY. A DISTURBANCE WILL INCREASE WIND WEDNESDAY AFTERNOON OVER THE FORECAST AREA AND HELP TO ELEVATE DAYTIME HUMIDITY. && .RIW WATCHES/WARNINGS/ADVISORIES... NONE. && SHORT TERM...BRANHAM LONG TERM...SKRBAC AVIATION...KPL FIRE WEATHER...BRANHAM
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RIVERTON WY 500 AM MDT TUE JUN 30 2009 WYZ001>020-022>030-011100- 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 TUE JUN 30 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING. .DAY ONE...TODAY AND TONIGHT THUNDERSTORMS ARE EXPECTED AGAIN OVER MUCH OF THE THIS AFTERNOON AND EVENING. THEY WILL BE MOST NUMEROUS OVER THE NORTHWEST. THE MAIN HAZARDS WILL BE LIGHTNING AND GUSTY WINDS TO 50 MPH...THOUGH SOME HEAVY RAIN AND SMALL HAIL ARE POSSIBLE OVER THE NORTHWEST. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY A DISTURBANCE WILL MOVE ACROSS SOUTHERN WYOMING WEDNESDAY BRINGING WITH IT SOME THUNDERSTORMS. A COLD FRONT WILL MOVE THROUGH BEHIND THE DISTURBANCE BRINGING COOLER TEMPERATURES AND INCREASED HUMIDITY. THIS WILL RAISE THE POTENTIAL FOR HEAVY RAINFALL WITH THUNDERSTORMS WEDNESDAY AND THURSDAY AFTERNOONS AND EVENINGS. AT LEAST ISOLATED THUNDERSTORMS ARE EXPECTED FRIDAY AS MONSOONAL MOISTURE ROTATES NORTHEAST ACROSS THE AREA. LATER FRIDAY INTO FRIDAY NIGHT...A COLD FRONT MAY DROP SOUTH AND SET THE STAGE FOR SOME STRONGER THUNDERSTORM OVER THE WEEKEND EAST OF THE CONTINENTAL DIVIDE. THUNDERSTORM COVERAGE WILL LIKELY DECREASE MONDAY. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ASKED TO REPORT ANY WIND GUSTS IN EXCESS OF 40 MPH OR HAIL WITH THUNDERSTORMS. THANK YOU. TEAM RIVERTON
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RIVERTON WY
454 PM MDT TUE JUN 30 2009
WYZ012-013-302345-
JACKSON HOLE-TETON AND GROS VENTRE MOUNTAINS-
454 PM MDT TUE JUN 30 2009
...SIGNIFICANT WEATHER ADVISORY FOR TETON COUNTY AND GRAND TETON
NATIONAL PARK UNTIL 545 PM MDT...
AT 449 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM ABOUT 10 MILES WEST
OF COLTER BAY VILLAGE...SOUTHWEST THROUGH THE GRAND TARGHEE SKI AREA
TO ABOUT 10 MILES WEST OF JACKSON...MOVING NORTHEAST AT 20 MPH.
ONE HALF INCH DIAMETER HAIL...AND WINDS AROUND 45 MPH ARE POSSIBLE
WITH THESE STORMS. DANGEROUS CLOUD-TO-GROUND LIGHTNING IS POSSIBLE
WITH THESE STORMS.
RESIDENTS AND VISITORS IN TETON COUNTY AS WELL AS GRAND TETON
NATIONAL PARK...INCLUDING THE LOCATIONS OF GRAND TARGHEE SKI
AREA...FONDA POINT CAMPGROUND...MOUNT MORAN...TETON PASS...MOOSE
...MORAN BAY...GRAND TETON...JACKSON AND LEIGH LAKE...SHOULD
MONITOR THE WEATHER SITUATION CLOSELY. LISTEN FOR POSSIBLE WARNINGS
AND BE PREPARED TO TAKE APPROPRIATE ACTION SHOULD SEVERE WEATHER
THREATEN.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
MOVE INDOORS IMMEDIATELY AS THIS STORM APPROACHES YOUR LOCATION. THIS
IS A POTENTIALLY DANGEROUS STORM. IF YOU ARE IN ITS PATH...YOU SHOULD
BE PREPARED FOR GUSTY WINDS...HAIL...AND DEADLY CLOUD TO GROUND
LIGHTNING. IF A STURDY STRUCTURE IS NOT AVAILABLE...SEEK SHELTER IN A
VEHICLE WITH THE WINDOWS UP.
&&
REPORT HAZARDOUS WEATHER TO THE NATIONAL WEATHER SERVICE OFFICE IN
RIVERTON AT 1-800-211-1448.
LAT...LON 4371 11106 4409 11082 4413 11024 4362 11057
4331 11069 4329 11105
TIME...MOT...LOC 2250Z 265DEG 16KT 4402 11074 4361 11100
4337 11110
MURRELLSPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 715 PM MDT TUE JUN 30 2009 WYZ002-003-005>007-010230- ABSAROKA MOUNTAINS-CODY FOOTHILLS-OWL CREEK AND BRIDGER MOUNTAINS- SOUTHEAST BIG HORN BASIN-SOUTHWEST BIG HORN BASIN- 715 PM MDT TUE JUN 30 2009 THROUGH 830 PM...EXPECT AN AREA OF SHOWERS AND ISOLATED THUNDERSTORMS TO CONTINUE MOVING EAST NORTHEAST ACROSS THE SOUTHERN ABSAROKA MOUNTAINS INTO THE SOUTHERN BIG HORN BASIN...AS WELL AS THE OWL CREEK MOUNTAINS. EXPECT...OCCASIONAL LIGHTNING...BRIEF HEAVY RAINFALL AND GUSTY WINDS NEAR 40 MPH WITH ANY THUNDERSTORMS. WYZ014>016-025-026-010230- UPPER GREEN RIVER BASIN-UPPER GREEN RIVER BASIN FOOTHILLS- UPPER WIND RIVER BASIN-WIND RIVER MOUNTAINS EAST- WIND RIVER MOUNTAINS WEST- 715 PM MDT TUE JUN 30 2009 THROUGH 830 PM...EXPECT AN AREA OF SHOWERS AND ISOLATED THUNDERSTORMS TO CONTINUE MOVING EAST ACROSS THE UPPER GREEN RIVER BASIN INTO THE WIND RIVER MOUNTAINS. EXPECT...OCCASIONAL LIGHTNING...BRIEF HEAVY RAINFALL AND GUSTY WINDS NEAR 40 MPH WITH ANY THUNDERSTORMS. 21
The Riverton/Lander radar (KRIW), 43 km away, was scanning. The volume nearest the first event began at 01:45 UTC.
2 thunderstorm wind. Local standard time, as filed.
Measured wind gusts of 57 to 61 mph lifted a 16x40 foot metal structure which was staked to the ground and tossed it 60 to 70 feet downwind.
The Riverton Regional Airport ASOS recorded a thunderstorm wind gust to 58 mph.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2009Every state in 2009This day in weather historyWarnings in Wyoming, June 2009
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: 175246, 170489.