A rapidly intensifying thunderstorm moved across Daggett County and produced large hail in the Dutch John area.
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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.
A rapidly intensifying thunderstorm moved across Daggett County and produced large hail in the Dutch John area.
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 Aug 18, 1:30 PM MST, 25 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 230 PM MDT SAT AUG 18 2007 .SHORT TERM...TONIGHT THROUGH MONDAY... SHOWERS AND THUNDERSTORMS CONTINUED THROUGH THE MORNING...MAINLY OVER THE NORTHWEST FOR THE SECOND DAY. THIS ACTIVITY WAS ASSOCIATED WITH ANOTHER SHORT WAVE IN THE MID-LEVEL SOUTHWEST FLOW. MEANWHILE... A STRONGLY WRAPPED VORT CENTER NORTH OF RIFLE IGNITED SOME STRONG THUNDERSTORMS OVER THE FLAT TOPS AND SUBSEQUENTLY ACROSS THE PARK RANGE AS IT DRIFTED TO THE NORTHEAST. THE EXTREME SOUTHERN ZONES OF THE CWFA WERE NOTICEABLY DRIER IN WV IMAGERY AND THIS HAS TRANSLATED INTO MOSTLY SUNNY AND DRY CONDITIONS SO FAR. ELSEWHERE...THUNDERSTORM ACTIVITY WAS MORE SCATTERED IN NATURE AND MAINLY OVER THE HIGHER TERRAIN. THE SHORTWAVE IMPACTING NORTHEAST UTAH WILL CONTINUE TO SUSTAIN THUNDERSTORMS OVER THE EXTREME NORTHERN PORTION OF THE CWFA THROUGH MUCH OF THE EVENING. THE REMAINDER OF THE CWFA SHOULD SEE DECREASING ACTIVITY WITH DIURNAL COOLING...ESPECIALLY SOUTH WHERE DRIER AIR WAS BEGINNING TO MOVE INTO THE AREA AS MENTIONED ABOVE. AS THE HIGH ELONGATES ZONALLY INTO ARIZONA...MONSOONAL FLOW WILL BE CUTOFF AND DRYING WILL BEGIN. LATEST GFS AND NAM SHOWED CWFA DRIER ON SUNDAY THAN IN PREVIOUS RUNS AND PARED BACK POPS A BIT MORE...FOCUSING CHANCES ALONG THE CONTINENTAL DIVIDE PRIMARILY. EVEN DRIER ON MONDAY WITH JUST A SLIGHT CHANCE OF THUNDERSTORMS ABOVE TREELINE ALONG THE CONTINENTAL DIVIDE. TEMPERATURES WILL WARM A BIT SUNDAY AND MONDAY IN RESPONSE TO INCREASED INSOLATION. IN CONTRAST...OVERNIGHT LOWS WILL BEGIN TO COOL AS THE AIRMASS DRIES AND CLOUDS CLEAR EARLIER THAN IN THE PAST FEW DAYS. .LONG TERM...MONDAY NIGHT THROUGH SATURDAY... DOOR TO THE MONSOONAL FLOW WILL REMAIN CLOSED DURING THE UPCOMING WORK WEEK AS A FLAT HIGH PRESSURE RIDGE TAKES UP RESIDENCE OVER THE DESERT SOUTHWEST. DAYTIME TEMPS WILL GENERALLY BE A LITTLE ABOVE NORMAL WHILE LOW TEMPS WILL BE A LITTLE COOLER THAN WE HAVE BEEN USED TOO DUE TO THE DRIER AIR MASS. && .AVIATION... ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH MID EVENING. THIS WILL BRING LOCAL MVFR CIGS TO THE AREA...ESPECIALLY OVER THE MOUNTAINS. GUSTY OUTFLOW WINDS TO 35 MPH AND SMALL HAIL WILL ACCOMPANY SOME OF THE THUNDERSTORMS. && .GJT WATCHES/WARNINGS/ADVISORIES... .CO...NONE. .UT...NONE. SHORT TERM...NL LONG TERM...DJC AVIATION...NL
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GRAND JUNCTION CO 545 AM MDT SAT AUG 18 2007 COZ001>014-017>023-UTZ022>025-027>029-191145- 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- 545 AM MDT SAT AUG 18 2007 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN UTAH AND WESTERN COLORADO. .DAY ONE...TODAY AND TONIGHT ISOLATED TO SCATTERED MOUNTAIN THUNDERSTORMS WILL DEVELOP THIS AFTERNOON THEN CONTINUE WELL INTO THE EVENING. ISOLATED THUNDERSTORMS WILL DEVELOP OVER THE VALLEYS...MAINLY LATE IN THE AFTERNOON AND IN THE EVENING. LOCALLY HEAVY RAIN IS POSSIBLE WITH SOME THUNDERSTORMS...ALONG WITH CLOUD TO GROUND LIGHTNING...SMALL HAIL AND GUSTY WINDS TO 40 MPH. HEAVY RAIN PRODUCING THUNDERSTORMS MAY PRODUCE LOCALIZED FLOODING OF SMALL STREAMS AND ARROYOS...AND URBAN AREAS. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY ISOLATED TO SCATTERED AFTERNOON AND EVENING THUNDERSTORMS WILL OCCUR ON SUNDAY...ESPECIALLY OVER THE MOUNTAINS. ONLY A FEW MOUNTAIN THUNDERSTORMS WILL DEVELOP EACH AFTERNOON DURING THE WORK WEEK DUE TO A DRIER WESTERLY FLOW. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED TODAY OR TONIGHT. HOWEVER... REPORTS RELAYED TO THE NATIONAL WEATHER SERVICE OF HEAVY RAIN... HAIL...AND ANY WEATHER RELATED DAMAGE WOULD BE GREATLY APPRECIATED. JDC/EH
The Grand Junction radar (KGJX), 232 km away, was scanning. The volume nearest the first event began at 20:56 UTC.
1 hail. Local standard time, as filed.
Daggett County Sheriff's Office reported golf ball size hail near Dutch John and penny-sized hail at the Flaming Gorge Dam. Minor street flooding was reported in Dutch John.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Utah in 2007Every state in 2007This day in weather historyWarnings in Utah, August 2007
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: 56793.