Severe thunderstorms broke out across the Northeast Plains of Colorado. The hardest hit areas were in Morgan, Logan and Weld Counties.
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.
Severe thunderstorms broke out across the Northeast Plains of Colorado. The hardest hit areas were in Morgan, Logan and Weld Counties. Hail up to softball size was reported in Morgan County, while hail up to golfball size occurred in Logan and Weld Counties.
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 Aug 8, 1:48 AM MST, 11 hours 12 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 248 AM MDT SAT AUG 8 2009 .SHORT TERM...FAIRLY DECENT SW FLOW ALOFT WILL BE OVER THE AREA THRU TONIGHT AS AN UPPER LEVEL TROUGH SLOWLY ADVANCES EASTWARD ACROSS THE NRN AND CNTRL ROCKIES. MEANWHILE A CDFNT WILL BE NR THE WYOMING BORDER BY 12Z AND THEN MOVE SOUTHWARD ACROSS MOST OF NERN CO BY 18Z BEFORE POSSIBLY STALLING OVER THE PALMER DIVIDE. EVENTUALLY DEEPER LOW LEVEL MOISTURE WILL ADVECT INTO NERN CO LATER THIS AFTN AND EVENING BEHIND FNT SETTING THE STAGE FOR TSTM DEVELOPMENT THIS EVENING FROM THE FOOTHILLS EASTWARD ONTO THE PLAINS. NAM SHOWS FAVORABLE QG ASCENT MOVING ACROSS THE AREA TONIGHT ALONG WITH SOME MID LEVEL COOLING WHICH WILL ENHANCE TSTM DEVELOPMENT ALONG AN NORTH OF FNTLY BNDRY. ENE LOW LEVEL FLOW COMBINED WITH 35-40 KTS OF SWLY MID LVL FLOW WILL PROVIDE FAVORABLE ENVIORNMENT FOR A FEW SVR TSTMS AND POSSIBLE A BRIEF TORNADO OR TWO AS WELL THIS EVENING. MEANWHILE WITH PRECPITABLE WATER VALUES FCST TO INCREASE TO AROUND AN INCH LOCALLY HEAVY RAINS WILL ALSO BE POSSIBLE. THIS PATTERN LOOKS SOMEWHAT SIMILAR TO WHAT OCCURRED ON JULY 20TH EXCEPT THAT FLOW ALOFT IS SWLY RATHER THAN NWLY. TEMPERATURES TODAY WILL BE COOLER BEHIND THE FNT EXCEPT SOUTH OF FNTL BNDRY OVER SERN ELBERT AND LINCOLN COUNTIES WHERE READINGS MAY BE SIMILAR TO FRI. FOR TONIGHT TSTM ACTIVITY MAY LINGER PAST MIDNIGHT OVER NERN CO AS QG ASCENT AND WAA PTRN CONTINUE OVER THE AREA NORTH OF FNTL BNDRY WHICH MAY ALLOW FOR SOME VERY HEAVY RAIN AMOUNTS IN A FEW SPOTS IF CONVECTION TRAINS OVER THE SAME AREAS. .LONG TERM...SAW NO NEED TO MAKE ANY CHANGES TO THE FORECAST PACKAGE THIS TIME AROUND. ON SUNDAY THE TAIL END OF THE NORTHERN ROCKIES SHORT WAVE TROUGH WILL BE OVER THE AREA ALONG WITH A LOW LEVEL AIRMASS THAT MIGHT BE MOIST AND UNSTABLE BEHIND A FRONTAL SURGE THAT MOVES INTO THE REGION SATURDAY EVENING. THE UPPER JET WILL ALSO BE OVER NORTHERN COLORADO AND POINTS NORTHWARD. SPC HAS PLACED THE NORTHEAST COLORADO PLAINS IN SLIGHT RISK FOR SUNDAY. HOWEVER...THE GFS AND NAM SOUNDINGS FOR SUNDAY AFTERNOON PAINT VASTLY DIFFERENT PICTURES CONCERNING WHAT THE MOISTURE AND INSTABILITY PROFILE LOOKS LIKE. FOLLOWING THE NAM/S SOLUTION WOULD LEAD TO QUITE OF CONVECTIVE ACTIVITY SUNDAY AFTERNOON. A LOT IS GOING TO DEPEND ON SHAT TRANSPIRES SATURDAY EVENING...SO FOR NOW AM STICKING WITH 10-20 PERCENT POPS SUNDAY AFTERNOON...WHICH IS QUITE CLOSE TO CLIMATOLOGY. THE REST OF THE WEEK FEATURES VERY LITTLE CHANGE AS THE UPPER TROUGH MOVES OFF TO THE NORTH AND THE SOUTHERN U.S. UPPER RIDGING GRADUALLY STRENGTHENS AND BUILDS WESTWARD. WEAK FLOW AROUND THE UPPER RIDGE WILL LIKELY BECOME FAIRLY MOIST OVER TIME IN A LATE SUMMER MONSOON-LIKE PATTERN. THE SUMMER HAS BEEN FAIRLY MOIST UP TO THIS POINT...AND NOW DOESN/T SEEM TO BE THE TIME FOR THAT TO CHANGE. A SLIGHT CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS ARE ABOUT ALL THAT CAN BE FORECAST. TEMPERATURES WILL ALSO BE AROUND TO SLIGHTLY WARMER THAN NORMAL. && .AVIATION...A CDFNT WILL MOVE INTO THE AREA AROUND 15Z WITH WINDS BECOMING MORE NNE. BY THIS AFTN APPEARS THE FNTL BNDRY WILL STALL OVER THE PALMER DIVIDE WITH LOW LEVEL FLOW ENE. LOW LEVEL MOISTURE WILL GRADUALLY INCREASE THRU THE AFTN INTO THE EVENING HOURS WITH SCT TSTMS DEVELOPING AFT 00Z. BASED ON THE SHEAR PROFILE SOME OF THE STORMS COULD BE SEVERE AND PRODUCE VERY HEAVY RAIN. SO COULD SEE BRIEF PERIOD OF MVFR/IFR CONDITIONS IF STORMS MOVE OVER THE AIRPORTS. LATE TONIGHT COULD SEE SOME STRATUS DEVELOP TOWARD SUNRISE WITH MVFR CONDTIONS POSSIBLE DUE TO LOW CEILINGS. && .BOU WATCHES/WARNINGS/ADVISORIES...NONE. RPK/KDRBY
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DENVER CO 1047 AM MDT SAT AUG 08 2009 COZ030>051-091200- 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- 1047 AM MDT SAT AUG 08 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL COLORADO. .DAY ONE...TODAY AND TONIGHT ISOLATED THUNDERSTORMS WILL DEVELOP OVER THE FRONT RANGE FOOTHILLS...PALMER DIVIDE AND ADJACENT PLAINS LATER THIS AFTERNOON...THEN SPREAD ACROSS THE REST OF NORTHEAST COLORADO THIS EVENING. THE STORMS WILL BECOME MORE NUMEROUS THIS EVENING...WHILE A FEW STORMS MAY BE SEVERE WITH LARGE HAIL AND DAMAGING WINDS. A COLD FRONT MOVED SOUTHWARD ACROSS NORTHEAST COLORADO THIS MORNING WHICH HELPED TO REPLENISH LOW LEVEL MOISTURE LEVELS ACROSS THE PLAINS. AN UPPER LEVEL DISTURBANCE WILL ALSO MOVE ACROSS THE REGION THIS EVENING WHICH WILL ENHANCE THUNDERSTORM DEVELOPMENT. WEST OF THE CONTINENTAL DIVIDE...THE AIRMASS IS MUCH DRIER...WITH ONLY ISOLATED STORMS THIS EVENING WITH GUSTY WINDS THE MAIN THREAT. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY MOISTURE LINGERING OVER NORTHEAST COLORADO ON SUNDAY AFTERNOON WILL COMBINE WITH DAYTIME HEATING...AND A WEAK UPPER LEVEL DISTURBANCE MOVING OVER THE STATE...TO PRODUCE SOME STRONG THUNDERSTORMS ON THE PLAINS IN THE AFTERNOON AND EARLY EVENING. THE THUNDERSTORMS WILL HAVE THE POTENTIAL TO PRODUCE HAIL AND GUSTY WINDS...BUT MAY ALSO BE SLOW MOVING AND CAPABLE OF PRODUCING HEAVY RAINFALL. WARM TEMPERATURES AND A SLIGHT CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS ARE ALSO EXPECTED TO CONTINUE THROUGH NEXT WEEK. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED ACROSS THE FRONT RANGE AND PLAINS AFTER 4 PM. ENTREKIN/COOPER
The Denver radar (KFTG), 33 km away, was scanning. The volume nearest the first event began at 20:00 UTC.
27 hail, 1 lightning, 1 tornado. Local standard time, as filed.
Lightning struck a very large tree in southwest Denver. The tree fell on fences and knocked down power lines.
A small tornado touched down but did no damage.
Large hail, up to grapefruit size, damaged corn crops. Most of the crop damage occurred north of State Highway 34 to Morgan County U, and along State Highway 144, east of State Highway 39. Damage to homes and vehicles was also reported. Minor damage was also reported at the Fort Morgan Golf Course.
Large hail broke out skylights in several recreational vehicles at an RV and trailer park in Greeley. Vehicles in several car dealerships in Greeley were damaged as well. The combination of heavy rain and hail also caused extensive street flooding. City Hall in Greeley reported minor flooding. Several basements were also flooded.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2009Every state in 2009This day in weather historyThe tornado archive for Colorado, 2009Warnings in Colorado, August 2009
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: 192577, 192419, 192581, 192420, 192424, 192423, 192433, 192422, 192421, 192425, 192426, 192427, 192428, 192429, 192430, 192431, 192432, 192434, 192435, 192436, 192437, 192438, 192439, 192440, 192441, 192442, 192443, 192458, 192459.