Hail, Arapahoe
- When
- July 17, 1:16 PM MST
- Where
- Arapahoe County, 13.12 mi NE of Byers
- Measured
- 1.75 in hail
- Property damage
- $5,000
- Reported by
- Trained Spotter
- Coordinates
- 39.850, -104.040
A severe thunderstorm produced large hail, up to the size of golfballs, and damaging thunderstorm winds. The combination of hail and wind broke several windows of a residence.
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 BOU wrote it up.
A severe thunderstorm produced large hail, up to the size of golfballs, and damaging thunderstorm winds. The combination of hail and wind broke several windows of a residence. The windshield of their vehicle was also cracked.
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 Denver/Boulder, CO wrote its last area forecast discussion before the first event at Jul 17, 1:53 AM MST, 11 hours 23 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 253 AM MDT THU JUL 17 2008 .SHORT TERM...UPPER LEVEL RIDGE TO FLATTEN SOME TODAY AS A SHORT WAVE MOVES ACROSS THE REGION. THIS WILL RESULT IN SLIGHTLY COOLER TEMPERATURES. EVEN THOUGH A WEAK COLD FRONT IS CURRENTLY MOVING ACROSS THE PLAINS...MOST LOCATIONS WILL BE NEAR THE 90 DEGREE MARK. MOISTURE TO FINALLY INCREASE OVER THE AREA TODAY. PRECIPITABLE WATER VALUES WILL BE OVER AN INCH FOR THE LOWER ELEVATIONS. SHOULD SEE SCATTERED THUNDERSTORMS FORM DURING THE AFTERNOON AND CONTINUE INTO THE EVENING. BEST CHANCE FOR STORMS WILL BE OVER THE FAR EASTERN PLAINS WHERE THE GREATEST MOISTURE WILL BE. HEAVY RAIN WILL BE THE BIGGEST CONCERN WITH THE STORMS. SHEAR WILL BE FAVORABLE FOR MULTICELLULAR STORMS...SO COULD SEE SOME TRAINING OF STORMS OVER THE SAME AREA. THIS COMBINED WITH THE SLOW STORM MOVEMENT (LESS THAN 20 MPH) AND THE INCREASED MOISTURE COULD POSE A THREAT FOR FLASH FLOODING. GREATEST THREAT FOR THIS AND A SEVERE STORM WILL BE EAST OF DENVER WHERE THE HIGHER MOISTURE AND CAPES WILL BE. LOW LEVEL MOISTURE TO INCREASE TONIGHT AND BY 12Z FRIDAY DEW POINTS WILL BE WELL INTO THE 50S ALL THE WAY TO THE FOOTHILLS SETTING UP ANOTHER CHANCE FOR STORMS FRIDAY. ENOUGH MOISTURE MAY BE PRESENT FOR LOW CLOUDS TO DEVELOP. .LONG TERM...ON FRIDAY...A MOIST AMS WILL REMAIN IN PLACE THROUGH FRIDAY MORNING. ALTHOUGH LOW LEVEL UPSLOPE WILL BE WEAKENING AS THE SFC HIGH OVER THE GREAT PLAINS SHIFTS EAST...BOTH MDLS SHOW PLENTY OF MSTR AND INSTBY IN THE AFTN. BOTH THE GFS/NAM SOUNDINGS INDICATE PW VALUES OF OVER ONE INCH AND CAPES FM 1400-1700 J/KG. SELY WINDS SHUD AID IN THE FORMATION OF A DENVER CYCLONE IN THE AFTN. BEST COVERAGE FOR TSTMS WOULD APPEAR TO BE IN AND NEAR THE FRONT RANGE FOOTHILLS AND PALMER DIVIDE. MAIN ADJUSTMENT INVOLVED KEEPING SLGT CHC POPS IN THE MORNING WITH SCT COVERAGE IN THE AFOREMENTIONED AREAS IN THE AFTN AND EVNG. THERE AGAIN APPEAR TO BE SOME UPPER LEVEL SUPPORT WITH A PASSAGE OF A SHORT WAVE TROF TO THE N OF THE STATE DURING THE AFTN/EVNG. ALSO OPTED TO COOL AFTN TEMPERATURES FOR FRIDAY...WITH PLENTY OF APPARENT CLOUD COVER...ESPECIALLY DURING THE MORNING HOURS. OVERALL THE REST OF THE GRIDS LOOK GOOD. AN UPPER LEVEL RIDGE WILL REBUILD OVER CO DURING THE WEEKEND WITH A DRIER AND WARMER AIRMASS IN PLACE. INCRG SUBSIDENCE WILL DCRS THE POTENTIAL FOR ANY TSTMS AS THE RIDGE BUILDS OVER THE 4CORNERS REGION. && .AVIATION...AIRMASS TO BECOME UNSTABLE THIS AFTERNOON WITH SCATTERED THUNDERSTORMS DEVELOPING AFTER 18Z. MAIN THREAT WITH THE STORMS WILL BE HEAVY RAIN AND GUSTY WINDS. MOISTURE WILL INCREASE THURSDAY NIGHT AND MAY EVEN SEE A FEW LOW CLOUDS FORM BETWEEN 08-14Z FRIDAY ACROSS THE PLAINS. && .BOU WATCHES/WARNINGS/ADVISORIES...NONE. && MEIER/COOPER
HAZARDOUS WEATHER OUTLOOK...CORRECTED NATIONAL WEATHER SERVICE DENVER CO 1108 AM MDT THU JUL 17 2008 COZ030>051-181200- JACKSON COUNTY BELOW 9000 FEET-WEST JACKSON AND WEST GRAND COUNTIES ABOVE 9000 FEET-GRAND AND SUMMIT COUNTIES BELOW 9000 FEET-SOUTH AND EAST JACKSON/LARIMER/NORTH AND NORTHEAST GRAND/ NORTHWEST BOULDER COUNTIES ABOVE 9000 FEET-SOUTH AND SOUTHEAST GRAND/WEST CENTRAL AND SOUTHWEST BOULDER/GILPIN/CLEAR CREEK/ SUMMIT/NORTH AND WEST PARK COUNTIES ABOVE 9000 FEET-LARIMER AND BOULDER COUNTIES BETWEEN 6000 AND 9000 FEET-JEFFERSON AND WEST DOUGLAS COUNTIES ABOVE 6000 FEET/GILPIN/CLEAR CREEK/NORTHEAST PARK COUNTIES BELOW 9000 FEET-CENTRAL AND SOUTHEAST PARK COUNTY-LARIMER COUNTY BELOW 6000 FEET/NORTHWEST WELD COUNTY-BOULDER AND JEFFERSON COUNTIES BELOW 6000 FEET/WEST BROOMFIELD COUNTY-NORTH DOUGLAS COUNTY BELOW 6000 FEET/DENVER/WEST ADAMS AND ARAPAHOE COUNTIES/ EAST BROOMFIELD COUNTY-ELBERT/CENTRAL AND EAST DOUGLAS COUNTIES ABOVE 6000 FEET-NORTHEAST WELD COUNTY-CENTRAL AND SOUTH WELD COUNTY-MORGAN COUNTY-CENTRAL AND EAST ADAMS AND ARAPAHOE COUNTIES- NORTH AND NORTHEAST ELBERT COUNTY BELOW 6000 FEET/NORTH LINCOLN COUNTY-SOUTHEAST ELBERT COUNTY BELOW 6000 FEET/SOUTH LINCOLN COUNTY-LOGAN COUNTY-WASHINGTON COUNTY-SEDGWICK COUNTY-PHILLIPS COUNTY- 1108 AM MDT THU JUL 17 2008 THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL COLORADO. .DAY ONE...TODAY AND TONIGHT SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS NORTHEAST COLORADO THROUGH THIS AFTERNOON...CONTINUING INTO THE EVENING HOURS. THE STORMS WILL BE SLOW MOVING AND COULD PRODUCE HEAVY RAIN WITH LOCALIZED FLASH FLOODING. A FEW OF THE STORMS ACROSS THE EASTERN PLAINS MAY ALSO BECOME SEVERE WITH LARGE HAIL THE BIGGEST THREAT. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY THE BEST CHANCE OF THUNDERSTORMS DURING THIS PERIOD WILL BE ON FRIDAY. WHILE ISOLATED SHOWERS AND THUNDERSTORMS MAY LINGER INTO THE EARLY MORNING HOURS FRIDAY...ANOTHER ROUND OF SCATTERED THUNDERSTORMS CAN BE EXPECTED IN THE AFTERNOON AND EVENING... ESPECIALLY IN THE SOUTHERN FRONT RANGE FOOTHILLS AND PALMER DIVIDE. THEY WILL AGAIN BE SLOW MOVING AND CAPABLE OF PRODUCING HEAVY RAINFALL ALONG WITH A THREAT OF FLASH FLOODING. ENOUGH INSTABILITY WILL ALSO EXIST FOR A COUPLE OF SEVERE STORMS WITH LARGE HAIL AND DAMAGING WINDS. IT WILL TURN DRIER AND WARMER AGAIN FOR THE WEEKEND INTO EARLY NEXT WEEK...WITH ONLY A SLIGHT CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED ACROSS THE EASTERN PLAINS THIS AFTERNOON. D-L/DBB
The Denver radar (KFTG), 44 km away, was scanning. The volume nearest the first event began at 20:14 UTC.
2 hail, 1 thunderstorm wind. Local standard time, as filed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2008Every state in 2008This day in weather historyWarnings in Colorado, July 2008
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: 124912, 124913, 124914.