Monsoon moisture coupled with a disturbance aloft to produce scattered thunderstorms over a large area. Thunderstorms along and near the Absaroka Range and Owl Creek Mountains became severe, with wind gusts over 60 mph at several locations.
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.
Monsoon moisture coupled with a disturbance aloft to produce scattered thunderstorms over a large area. Thunderstorms along and near the Absaroka Range and Owl Creek Mountains became severe, with wind gusts over 60 mph at several locations. The highest gust recorded was 73 mph about eight miles west of Thermopolis.
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 Jul 27, 1:51 PM MST, 3 hours 4 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RIVERTON WY 251 PM MDT FRI JUL 27 2012 .SHORT TERM...TONIGHT THROUGH MONDAY MONSOONAL PLUME IS MOVING THROUGH THE FORECAST AREA TODAY WITH SEVERAL AREAS OF CONCERN INTO THE EVENING HOURS. THE HIGHEST THREAT OF SEVERE WIND GUSTS FROM HIGH BASED STORMS IS AROUND NATRONA COUNTY BUT ALSO EXTENDS INTO SWEETWATER AND FREMONT COUNTY. IN THE FAR WEST...CAPE IS BUILDING ALONG AND WEST OF THE BORDER AND WE EXPECT STORMS TO FIRE THERE LATER THIS AFTERNOON AND MOVE INTO THE NORTHWEST ESPECIALLY. A FEW STRONGER STORMS HAVE BEEN MOVING ACROSS THE NORTHERN PART OF YNP PARK OVER THE LAST 1 TO 2 HOURS. A LITTLE BETTER MOISTURE EXISTS IN THE FAR NORTH WHICH COULD AID IN A FEW STRONGER STORMS...INCLUDING NORTHERN AND EASTERN JOHNSON. THE PLUME IS SHUNTED TO THE EAST AND SOUTH ON SATURDAY AS THE RIDGE REBUILDS OVER THE AREA. IT STILL LOOKS LIKE THE BEST BEST OF ISOLATED STORMS WILL BE OVER THE FAR SOUTH...EAST... NORTHERN BORDER AND A FEW IN THE MOUNTAINS. NOT A LOT OF CHANGE FOR SUNDAY OR MONDAY. CONTINUED VERY WARM TO HOT EACH DAY. .LONG TERM...MONDAY NIGHT THROUGH FRIDAY MODELS STILL INDICATING A BROADENING OF THE HIGH PRESSURE RIDGE OVER THE ROCKIES ASSOCIATED WITH THE HIGH OVER THE SOUTHWEST UNITED STATES AND SOUTHERN PLAINS THROUGH MID WEEK. THIS WOULD TRANSLATE INTO A DRY FORECAST WITH MAINLY A WEST SOUTHWEST STEERING FLOW KEEPING MOST OF ANY MONSOON MOISTURE TO OUR SOUTH. THEN A TROUGH APPROACHES FROM THE WEST BY THURSDAY AND FRIDAY WITH ONLY ISOLATED ACTIVITY INDICATED FOR NOW OVER THE HIGHER TERRAIN BY THURSDAY. .AVIATION.../00Z ISSUANCE/ SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE UNTIL 00Z. WIND GUSTS TO 35 KNOTS WILL BE POSSIBLE ALONG WITH LOCAL MVFR CONDITIONS. THE SHOWER AND STORM COVERAGE WILL BECOME ISOLATED AFTER 00Z THROUGH 12Z SATURDAY. EAST OF THE CONTINENTAL DIVIDE...SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE TO FORM ALONG THE WIND RIVER AND ABSAROKA MOUNTAINS AND THE BIGHORN MOUNTAINS. THE SHOWERS AND STORMS WILL PROGRESS EAST TO NORTHEAST OVER THE LOWER ELEVATIONS THROUGH THE REMAINDER OF THE AFTERNOON HOURS UNTIL AROUND 03Z. WIND GUSTS TO 45 KNOTS WILL BE POSSIBLE...ESPECIALLY IN NATRONA COUNTY INCLUDING KCPR ALONG WITH LOCAL MVFR CONDITIONS. THE ACTIVITY WILL DECREASE TO ISOLATED FROM 06Z THROUGH 12Z SATURDAY. FOR KJAC AIRPORT TODAY AND THIS EVENING...SCATTERED SHOWERS AND STORMS WILL CONTINUE ACROSS EASTERN IDAHO AND OVER THE TETON MOUNTAINS. SOME OF THIS ACTIVITY WILL IMPACT THE KJAC AIRPORT OR IN THE VICINITY UNTIL 00Z. WIND GUSTS TO 30 TO 40 KNOTS AND MVFR CONDITIONS WILL OCCUR ONLY IF A STORM DIRECTLY IMPACTS THE AIRPORT. EXPECT THE ACTIVITY TO DECREASE AFTER 00Z SATURDAY AS THE STORMS WILL MOVE EAST NORTHEAST OUT OF THE REGION. .FIRE WEATHER... VERY STRONG TO DAMAGING WINDS ARE POSSIBLE EAST OF THE DIVIDE INTO THE EARLY EVENING...ESPECIALLY ACROSS THE CENTRAL AND SOUTH PART OF THE DISTRICT. STRONGER...WETTER STORMS ARE POSSIBLE IN THE NORTHWEST AND FAR NORTHERN PART OF THE DISTRICT. THE RIDGE OF HIGH PRESSURE WILL NOSE BACK INTO THE AREA OVER THE WEEKEND WITH ISOLATED THUNDERSTORMS MAINLY CONFINED TO THE FAR SOUTH...EAST...NORTH AND IN THE MOUNTAINS. OTHERWISE...IT WILL BE VERY WARM TO HOT WITH GUSTY WINDS NEAR ANY THUNDERSTORMS. && .RIW WATCHES/WARNINGS/ADVISORIES...NONE. && SHORT TERM...SKRBAC LONG TERM...LIPSON AVIATION...LIPSON FIRE WEATHER...SKRBAC
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RIVERTON WY 500 AM MDT FRI JUL 27 2012 WYZ001>020-022>030-281100- 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 FRI JUL 27 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING. .DAY ONE...TODAY AND TONIGHT SCATTERED THUNDERSTORMS ACROSS THE HIGHER ELEVATIONS AND IN THE WEST TODAY AND TONIGHT...WITH ISOLATED TO WIDELY SCATTERED THUNDERSTORMS EXPECTED EAST OF THE DIVIDE AND IN THE LOWER ELEVATIONS. SOME OF THE STORMS ARE CAPABLE OF PRODUCING WIND GUSTS IN EXCESS OF 50 MPH AND FREQUENT CLOUD TO GROUND LIGHTNING. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY SUNDAY AND THURSDAY...ISOLATED THUNDERSTORMS ACROSS THE SOUTH AND EAST. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ENCOURAGED TO REPORT RAINFALL AMOUNTS AND ANY WIND GUSTS GREATER THAN 40 MPH TO THE NATIONAL WEATHER SERVICE IN RIVERTON AT 1-800-211-1448. THANK YOU. TEAM RIVERTON
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 1247 PM MDT FRI JUL 27 2012 WYZ001-271930- YELLOWSTONE NATIONAL PARK- 1247 PM MDT FRI JUL 27 2012 A CLUSTER OF THUNDERSTORMS WILL CONTINUE TO MOVE NORTHEAST TOWARDS THE NORTHEAST ENTRANCE OF YELLOWSTONE NATIONAL PARK. THE STORMS WILL IMPACT TOWER FALLS...THE LAMAR VALLEY...ICE BOX CANYON AND THE NORTHEAST ENTRANCE BETWEEN NOW AND 145 PM. THE THUNDERSTORMS WILL BE CAPABLE OF PRODUCING WIND GUSTS TO 45 MPH...CLOUD TO GROUND LIGHTNING...AND A BRIEF PERIOD OF HEAVY RAIN. SEEK A SAFE INDOOR SHELTER IF STORMS APPROACH YOUR LOCATION. SKRBAC
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 206 PM MDT FRI JUL 27 2012 WYZ020-022-272100- CASPER MOUNTAIN-NATRONA COUNTY LOWER ELEVATIONS- 200 PM MDT FRI JUL 27 2012 A CLUSTER OF THUNDERSTORMS WILL MOVE NORTHEAST ACROSS SOUTHERN AND EASTERN NATRONA COUNTY THROUGH 3 PM. EXPECT 45 TO 55 MPH WINDS WITH THIS STORM ALONG WITH BRIEF HEAVY RAINFALL AND OCCASIONAL CLOUD TO GROUND LIGHTNING STRIKES. CASPER MOUNTAIN WILL LIKELY BE AFFECTED BY THESE STORMS. THE CITY OF CASPER MAY ALSO GET GLANCED FROM THIS CLUSTER OF STORMS...ESPECIALLY SOUTH CASPER SEEK A SAFE INDOOR SHELTER IF STORMS APPROACH YOUR LOCATION. LIPSON
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 257 PM MDT FRI JUL 27 2012 WYZ020-022-272200- CASPER MOUNTAIN-NATRONA COUNTY LOWER ELEVATIONS- 257 PM MDT FRI JUL 27 2012 A CLUSTERS OF SHOWERS AND THUNDERSTORMS WILL CONTINUE TO MOVE NORTHEAST ACROSS SOUTHERN...CENTRAL AND EASTERN NATRONA COUNTY THROUGH 4 PM. THE TOWN OF HIGHLAND HAD A PEAK WIND GUST OF 53 MPH AT 245 PM. EXPECT 45 TO 60 MPH WIND GUSTS WITH SOME OF THESE STORM CELLS ALONG WITH BRIEF HEAVY RAINFALL AND OCCASIONAL CLOUD TO GROUND LIGHTNING STRIKES. CASPER AND CASPER MOUNTAIN WILL LIKELY BE IN THE PATH OF SOME OF THESE STORM CELLS. SEEK A SAFE INDOOR SHELTER IF STORMS APPROACH YOUR LOCATION. LIPSON
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RIVERTON WY
425 PM MDT FRI JUL 27 2012
WYZ001-272315-
YELLOWSTONE NATIONAL PARK WY-
425 PM MDT FRI JUL 27 2012
...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN PARK AND
SOUTHWESTERN PARK COUNTIES UNTIL 515 PM MDT...
AT 418 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM NEAR DIVIDE LAKE...OR 14 MILES NORTH OF WEST
YELLOWSTONE...MOVING NORTHEAST AT 20 MPH. ADDITIONAL STORMS ARE
PRESENT IN THE AREA.
WIND GUSTS UP TO 45 MPH ARE EXPECTED WITH AND PRECEDING THIS
STORM...ALONG WITH SMALL HAIL.
THIS STORM WILL BE NEAR...
DIVIDE LAKE AROUND 430 PM MDT.
GALLATIN LAKE AROUND 440 PM MDT.
CACHE LAKE AND ELECTRIC PEAK AROUND 505 PM MDT.
SWAN LAKE AROUND 510 PM MDT.
MAMMOTH AROUND 515 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 4500 11106 4501 11084 4499 11073 4499 11059
4486 11045 4474 11105
TIME...MOT...LOC 2224Z 234DEG 17KT 4488 11105
BRANHAMSPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 516 PM MDT FRI JUL 27 2012 WYZ001-280015- YELLOWSTONE NATIONAL PARK- 516 PM MDT FRI JUL 27 2012 SHOWERS AND THUNDERSTORMS CONTINUE TO IMPACT THE MAJORITY OF YELLOWSTONE NATIONAL PARK THIS EVENING. THUNDERSTORMS MAY PRODUCE GUSTY WIND IN EXCESS OF 40 MPH...AND MAY CONTAIN SMALL HAIL. STORMS MOVING THROUGH THE NORTHWESTERN HALF OF THE PARK HAVE DEMONSTRATED SOME FREQUENT LIGHTNING. THOSE WITH OUTDOOR INTERESTS SHOULD SEEK A STURDY INDOOR SHELTER IF STORMS APPROACH. PLEASE REPORT SIGNIFICANT WEATHER TO THE NATIONAL WEATHER SERVICE IN RIVERTON AT 1-800-211-1448. BRANHAM
The Billings radar (KBLX), 136 km away, was scanning. The volume nearest the first event began at 23:56 UTC.
6 thunderstorm wind. Local standard time, as filed.
A cluster of thunderstorms formed over the Absaroka Range and moved east, producing a 72 mph wind gust at a remote observing station.
A strong thunderstorm produced a 58 mph wind gust at a remote observing station.
A thunderstorm moved off the Absaroka Range and produced a 62 mph wind gust at an automated Wyoming Department of Transportation weather station along State Highway 120 north of Meeteetse.
A thunderstorm moved across the southern Absaroka Range and sent strong outflow wind southeast across the western Owl Creek Mountains. A remote weather station recorded a peak wind gust of 64 mph.
A 73 mph wind gust was reported in association with a thunderstorm eight miles west of Thermopolis. The gust was recorded at a residence with an automated weather station.
A strong thunderstorm produced a 59 mph wind gust at an automated weather station on Boysen Peak.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2012Every state in 2012This day in weather historyWarnings in Wyoming, July 2012
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: 396357, 396358, 396359, 396363, 396366, 396368.