Colorado, 2008

Hail and Damaging Wind in Colorado, July 17, 2008

July 17, 2008 · NWS BOU · 3 events in 2 counties and zones

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.

Where it happened

Every event with a place to put it. Tap one for its entry below.

  • Tornadoes
  • Tropical storms and surge
  • Floods
  • Wind
  • Hail
  • Winter weather
  • Heat and drought
  • Cold
  • Fire, smoke and dust
  • Marine and coastal
  • Other

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The toll

Deaths
0
Injuries
0
Property damage
$5,000
Crop damage
None recorded
Events
3

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.

What happened

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.

What forecasters said that day

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, Jul 17, 1:53 AM MST, 11 hours 23 minutes before
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, Jul 17, 10:08 AM MST, 3 hours 8 minutes before
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 radar

The Denver radar (KFTG), 44 km away, was scanning. The volume nearest the first event began at 20:14 UTC.

Open the radar archive at this moment

Event by event

2 hail, 1 thunderstorm wind. Local standard time, as filed.

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

Hail, Arapahoe

When
July 17, 1:55 PM MST
Where
Arapahoe County, 10.16 mi NE of Deer Trail
Measured
1.75 in hail
Reported by
Broadcast Media
Coordinates
39.720, -103.910

Thunderstorm Wind, Lincoln

When
July 17, 3:09 PM MST
Where
Lincoln County, 4.71 mi SE of Shaw
Measured
52 kt (60 mph) estimated gust
Reported by
Trained Spotter
Coordinates
39.450, -103.270

What these are

Hail
Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
Thunderstorm Wind
Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

More

Every storm in Colorado in 2008Every state in 2008This day in weather historyWarnings in Colorado, July 2008

Sources

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.