Abundant moisture across the area and daytime heating resulted in the development of strong afternoon thunderstorms.
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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 GJT wrote it up.
Abundant moisture across the area and daytime heating resulted in the development of strong afternoon thunderstorms.
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 Grand Junction, CO wrote its last area forecast discussion before the first event at Jul 21, 1:45 PM MST, 17 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 245 PM MDT WED JUL 21 2010 .SHORT TERM...TONIGHT THROUGH FRIDAY SCREAMING MESSAGE INTO THIS EVENING IS THE FF POTENTIAL FOR THE SOUTHERN PORTION OF OUR CWA...AND POTENTIAL FOR STORMS WITH HAIL IN THE NORTHERN PORTION...EVEN A FEW STORMS WITH HAIL UP TO AROUND 1.5 INCHES DIAMETER...AS CAPES REMAIN RELATIVELY LARGE...PRESENTLY UP TO ABOUT 1500 J/KG. FF WATCH IN OUR SOUTHERN AREA WILL CONTINUE AT LEAST UNTIL 9 PM MDT WHERE GROUND IS ALREADY SATURATED IN SOME AREAS. THEN PACIFIC TROUGH THAT HAS MOVED WELL INLAND SHOULD RIDE ACROSS JUST N OF OUR CWA ON THURSDAY AND TURN THE FLOW TO THE WEST ACROSS NORTHERN PORTION OF OUR CWA ALONG WITH BRINGING IN DRIER AIR. DO NOT EXPECT THIS SITUATION TO IMPACT SOUTHERN PORTION OF OUR CWA TOO MUCH...WITH JUST SLIGHTLY LOWER PRECIPITABLE WATER...PW...VALUES. LITTLE CHANGE EXPECTED WITH THIS GENERAL PATTERN THROUGH FRIDAY... DRIER AIR MASS CONTINUING NORTH AND STILL RATHER MOIST SOUTH THOUGH WITH PW VALUES DOWN EVEN A LITTLE BIT MORE THAN THURSDAY. WITH FEWER CLOUDS AND SHOWERS NORTHERN PORTION OF OUR CWA THURSDAY AND FRIDAY...EXPECT SOME RECOVERY ON THE MAX TEMPERATURES...AND LITTLE COOLER NIGHTS. HOWEVER...MAY NOT SEE MUCH MAX TEMPERATURE RECOVERY IN MOST SOUTHERN CWA ZONES. .LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY... HIGH PRESSURE REBUILDS OVER THE SWRN STATES AND BECOMES CENTERED NEAR THE 4 CORNERS BY SATURDAY. THIS WILL CONTINUE TO BRING A MOIST SOUTHWESTERLY FLOW INTO THE SOUTHERN 2/3 OF OUR CWA ALONG WITH SCATTERED CONVECTION. A WEST-NORTHWESTERLY FLOW WILL SLIGHTLY LIMIT MOISTURE ACROSS THE EXTREME NORTH BUT THERE WILL STILL BE ENOUGH MSTR FOR ISOLATED TO SCATTERED AFTERNOON AND EVENING SHOWERS OR THUNDERSTORMS. AS YET UNRESOLVABLE SHRT WVS WILL ACT AS A TRIGGER AND INCREASE AREAL COVERAGE AND INTENSITY OF STORMS. HIGH PRESSURE WILL GET PUSHED EASTWARD AND SOUTHWARD BY EARLY NEXT WORK WEEK AS YET ANOTHER TROF MOVES INTO THE WEST COAST. THIS WILL BRING A MORE SOUTHERLY FLOW ACCOMPANIED BY DEEPER MSTR OVER OUR ENTIRE CWA. THIS SHOULD RESULT IN MORE WIDESPREAD CONVECTION... BUT DUE TO UNCERTAINTY THAT FAR OUT WILL LEAVE POPS IN SCATTERED CATEGORY. TEMPERATURES WILL BE NEAR OR A LITTLE ABOVE CLIMATOLOGY. && .AVIATION... SHOWERS AND THUNDERSTORMS WILL CONTINUE WELL INTO THE EVENING RESULTING IN MTN OBSCURATION AND MVFR CONDITIONS. LOCAL IFR CIGS/VSBYS ARE POSSIBLE IN HEAVY RAINFALL. EXPECT IMPROVED CONDITIONS ACROSS THE NORTH THURSDAY...BUT NUMEROUS SHOWERS AND THUNDERSTORMS ARE STILL ANTICIPATED FOR AREAS S OF I-70. THIS WILL RESULT IN MTN OBSCURATION AND MVFR CONDITIONS. LOCAL IFR CIGS/VSBYS WILL BE POSSIBLE IN HEAVY RAINFALL. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE UT...NONE SHORT TERM.....JRP LONG TERM......MC AVIATION.......MC
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GRAND JUNCTION CO 600 AM MDT WED JUL 21 2010 COZ001>014-017>023-UTZ022>025-027>029-221138- ANIMAS RIVER BASIN-ARCHES/GRAND FLAT-CANYONLANDS/NATURAL BRIDGES- CENTRAL COLORADO RIVER BASIN- CENTRAL GUNNISON AND UNCOMPAHGRE RIVER BASIN- CENTRAL YAMPA RIVER BASIN-DEBEQUE TO SILT CORRIDOR- EASTERN UINTA BASIN-EASTERN UINTA MOUNTAINS- ELKHEAD AND PARK MOUNTAINS-FLAT TOPS- FOUR CORNERS/UPPER DOLORES RIVER- GORE AND ELK MOUNTAINS/CENTRAL MOUNTAINS-GRAND AND BATTLEMENT MESAS- GRAND VALLEY-LA SAL AND ABAJO MOUNTAINS-LOWER YAMPA RIVER BASIN- NORTHWEST SAN JUAN MOUNTAINS-PARADOX VALLEY/LOWER DOLORES RIVER- ROAN AND TAVAPUTS PLATEAUS-SAN JUAN RIVER BASIN-SOUTHEAST UTAH- SOUTHWEST SAN JUAN MOUNTAINS-TAVAPUTS PLATEAU- UNCOMPAHGRE PLATEAU AND DALLAS DIVIDE-UPPER GUNNISON RIVER VALLEY- UPPER YAMPA RIVER BASIN-WEST ELK AND SAWATCH MOUNTAINS- 600 AM MDT WED JUL 21 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN UTAH AND WESTERN COLORADO. .DAY ONE...TODAY AND TONIGHT THUNDERSTORMS AND SHOWERS ARE EXPECTED AGAIN TODAY AS DISTURBANCES CONTINUE TO MOVE OVER UTAH AND COLORADO. MAIN CONCERN WILL BE GUSTY WINDS AT THE SURFACE. ALL AREAS IN UTAH AND COLORADO HAVE A CHANCE TO SEE SOME PRECIPITATION TODAY. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY MOISTURE WILL INCREASE OVER THE AREA WITH A SLIGHT CHANCE OF THUNDERSTORMS OVER LOWER ELEVATIONS AND A CHANCE OF THUNDERSTORMS OVER THE MOUNTAINS THURSDAY THROUGH THE WEEKEND THOUGH AREAS SOUTH OF INTERSTATE 70 WILL BE FAVORED. .SPOTTER INFORMATION STATEMENT SPOTTER ACTIVATION IS NOT ANTICIPATED TODAY OR TONIGHT.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE GRAND JUNCTION CO 130 PM MDT WED JUL 21 2010 UTZ023-024-212015- EASTERN UINTA BASIN UT-EASTERN UINTA MOUNTAINS UT- 130 PM MDT WED JUL 21 2010 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN UINTAH COUNTY UNTIL 215 PM MDT... AT 125 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 10 MILES SOUTHWEST OF WHITEROCKS...MOVING EAST AT 30 MPH. HAIL UP TO THE SIZE OF PENNIES IS EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN AND FREQUENT LIGHTNING. LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE... WHITEROCKS... MAESER... VERNAL... IF THREATENING WEATHER APPROACHES YOUR AREA...TAKE SHELTER IN A STURDY BUILDING. WHEN THUNDER ROARS...GO INDOORS. HEAVY RAINFALL...WHICH MAY RESULT IN MINOR FLOODING...IS ALSO LIKELY. DO NOT DRIVE YOUR VEHICLE ON A FLOODED ROADWAY. PRINGLE
The Grand Junction radar (KGJX), 165 km away, was scanning. The volume nearest the first event began at 21:02 UTC.
1 flash flood. Local standard time, as filed.
At least 6 inches of water and debris rushed across Highway 211 between the junction of Highway 191 and Newspaper Rock. Also, pea-sized hailstones accumulated in some areas up to 6 inches deep.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Utah in 2010Every state in 2010This day in weather historyWarnings in Utah, 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: 247372.