1 lightning, as filed by the National Weather Service.
Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. 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 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 18, 1:50 PM MST, 1 hour 40 minutes earlier.
NORTHEAST AND NORTH CENTRAL COLORADO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 250 PM MDT MON AUG 18 2003 CORRECTED WORDING IN 2ND PARAGRAPH SHORT TERM DISCUSSION...VIGOROUS UPPER LOW FINALLY CREATING SOME SIGNIFICANT WEATHER OVER THE CWA. WHILE AIRMASS IS MODERATELY UNSTABLE...ENOUGH SHEAR PRESENT TO PRODUCE A FEW SEVERE STORMS. SEVERE THUNDERSTORM WATCH GOES TIL 01Z FOR THE PLAINS. STORMS EXPECTED TO SLOWLY WEAKEN/MOVE EASTWARD THIS EVENING AND OVERNIGHT. WILL CARRY SCATTERED POPS MOST AREAS WITH LIKELY POPS CONFINED TO NORTHEAST CORNER WHERE UPPER SUPPORT LASTS THROUGH THE NIGHT. AS PER LAST FEW NIGHTS...WILL KEEP SOME CONVECTION THROUGH TOMORROW MORNING WHERE UPPER SUPPORT IS BEST...THIS TIME IN THE NORTHEAST CORNER. OTHERWISE...TOMORROW SHOULD BE MOSTLY DRY AS SUBSIDENCE AND DRYING MOVING IN BEHIND TROF AXIS WILL EFFECTIVELY SQUASH CONVECTIVE DEVELOPMENT...SIMILAR TO WHATS OCCURRING RIGHT NOW IN WESTERN WYOMING...EASTERN UTAH...AND NORTHWEST CORNER OF COLORADO. HAVE LEFT ONLY ISOLATED AFTERNOON POPS FROM THE FOOTHILLS EASTWARD WHERE THERE MAY JUST ENOUGH LINGERING MOISTURE TO OFFSET SUBSIDENCE. TEMPS START A WARMUP WHICH WILL CONTINUE THROUGH THE WEEK. BARJENBRUCH LONG TERM DISCUSSION...DRAGGING LOW PRES TROF IS A BIT SLOWR TO DEPART THE AREA ACCORDING TO ALL OF THE 12Z RUNS THIS MRNG. FIERCE SUBSIDENCE BEGINS THOUGH AND PCPN WL COME TO AN END BY ELY TUES EVENING. BUT WL KP SCT SHWRS AND TSTMS GOING FOR THE NORTHEAST PLAINS FOR A BIT LNGR SINCE THE MESOETA KPS SOME POT VORTICITY ACRS THE NERN CORNER OF THE STATE WITH STEEP LAPSE RATES THRU 06Z TUES NGT. WED...H5 RDG WL RAPIDLY AMPLIFY ACRS SRN UT AND SWRN COLORADO...BUT NWLY FLOW ALF THRU THE DAY SHUD KP TEMPS MAINLY IN THE 80S TO LWR 90S. AIRMASS WL BE COMPLETELY DRY SINCE SUBTROPICAL MSTR WL STILL BE BOTTLED UP IN SRN ARIZONA. WL RMV ALL POPS FOR WED. THURSDAY AND BYND...12Z GFS A LTL DIFFERENT THAN PRVS RUNS CONCERNING PSN OF RDG ACRS THE SOUTHWEST. EARLIER MDL RUNS KEPT THE RDG ACRS CO AND NEW MEX THRU THE WEEKEND...BUT NOW LATEST MDL GDNC INDG RDG MAY GRADUALLY PROGRESS EWD INTO THE MIDWEST. THIS WOULD ALLOW SOME MSTR FROM OLD MEXICO TO INFILTRATE THE RDG CIRCULATION OVER THE NEXT FEW DAYS. LATEST NCEP DISCUSSION ALLUDES TO POOR MDL CONSISTENCY AND I AM INCLINED TO AGREE. WL TEMPER FCST MAX TEMPS A LTL AND ADD SOME ISOLD POPS TO THE FNT RANGE BUT OTWS WL LV XTND FCST ALONE FOR NOW. 46 .DEN...NONE.
COZ030>051-191200- HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DENVER CO 1100 AM MDT MON AUG 18 2003 THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL COLORADO. .DAY ONE...TODAY AND TONIGHT SCATTERED THUNDERSTORMS WILL QUICKLY DEVELOP AND SPREAD ACROSS THE MOUNTAINS THROUGH THE NOON HOUR AND ACROSS THE PLAINS OF NORTHEAST COLORADO BETWEEN 1 AND 4 PM. WIND SHEAR HAS INCREASED ACROSS THE AREA...SO ONE OR TWO SUPERCELL THUNDERSTORMS MAY DEVELOP BY MID AFTERNOON ACROSS THE PLAINS. THE BIGGEST THREAT FROM THE STORMS TODAY WILL BE LARGE HAIL...ALTHOUGH ISOLATED DAMAGING WIND GUSTS CAN ALSO BE ANTICIPATED. THE AMOUNT OF MOISTURE IN THE ATMOSPHERE HAS ALSO INCREASED...SO HEAVY RAIN WILL OCCUR WITH THE STRONGER STORMS. THIS MAY PRODUCE FLOODING PROBLEMS IN URBAN LOCATIONS AS WELL AS THE BURN AREAS IN THE FOOTHILLS. AN UNSEASONABLY STRONG UPPER LEVEL LOW PRESSURE SYSTEM MOVING ALONG THE WYOMING AND COLORADO BORDER WILL BE RESPONSIBLE FOR THE THUNDERSTORMS...SOME OF WHICH WILL LINGER PAST MIDNIGHT. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY TUESDAY...THE TROUGH OF LOW PRESSURE IS EXPECTED TO MOVE NORTHEAST INTO THE DAKOTAS. HOWEVER...ABUNDANT MID AND HIGH LEVEL MOISTURE WILL REMAIN...PARTICULARLY ACROSS THE NORTHEAST CORNER OF THE STATE. WEST TO NORTHWEST WINDS ALOFT WILL INCREASE OVER THE AREA WHICH WILL CREATE SOME SHEAR IN THE ATMOSPHERE DURING THE AFTERNOON. AS A RESULT...THERE WILL BE A CHANCE OF SEVERE THUNDERSTORMS...MAINLY EAST OF AKRON. AFTER TUESDAY...A MUCH DRIER AND WARMER WEATHER PATTERN WILL BECOME ESTABLISHED ACROSS THE STATE AS HIGH PRESSURE REBUILDS ACROSS THE SOUTHWEST. ONLY ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS ARE EXPECTED IN THE MOUNTAINS...OTHERWISE CONDITIONS WILL REMAIN DRY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE REQUIRED OVER THE FRONT RANGE METRO AREAS AND EASTERN PLAINS BY 1 PM. BARJENBRUCH/046
LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DENVER CO
144 PM MDT MON AUG 18 2003
...PRELIMINARY STORM REPORT FOR AUGUST 18 2003...
TIME(MDT) .....CITY LOCATION.....STATE ...EVENT/REMARKS...
....COUNTY LOCATION....
0138 PM AURORA CO 0.75 INCH HAIL
08/18/03 ARAPAHOE
JKLOCAL STORM REPORT
NATIONAL WEATHER SERVICE DENVER CO
150 PM MDT MON AUG 18 2003
...PRELIMINARY STORM REPORT FOR AUGUST 18 2003...
TIME(MDT) .....CITY LOCATION.....STATE ...EVENT/REMARKS...
....COUNTY LOCATION....
0138 PM AURORA CO 0.75 INCH HAIL
08/18/03 ARAPAHOE
0140 PM LONE TREE CO 2.75 INCH HAIL
08/18/03 DOUGLAS
JKLOCAL STORM REPORT...UPDATED
NATIONAL WEATHER SERVICE DENVER CO
318 PM MDT MON AUG 18 2003
...PRELIMINARY STORM REPORT FOR AUGUST 18 2003...
TIME(MDT) .....CITY LOCATION.....STATE ...EVENT/REMARKS...
....COUNTY LOCATION....
0205 PM 9 SE AURORA CO 0.75 INCH HAIL
08/18/03 ARAPAHOE
0140 PM LONE TREE CO 2.75 INCH HAIL
08/18/03 DOUGLAS
0138 PM AURORA CO 0.75 INCH HAIL
08/18/03 ARAPAHOE
0117 PM 2 NE GLENHAVEN CO 1.00 INCH HAIL
08/18/03 LARIMER
BENTONLOCAL STORM REPORT...UPDATED
NATIONAL WEATHER SERVICE DENVER CO
422 PM MDT MON AUG 18 2003
...PRELIMINARY STORM REPORT FOR AUGUST 18 2003...
TIME(MDT) .....CITY LOCATION.....STATE ...EVENT/REMARKS...
....COUNTY LOCATION....
0420 PM LAST CHANCE CO 0.75 INCH HAIL
08/18/03 WASHINGTON
0205 PM 9 SE AURORA CO 0.75 INCH HAIL
08/18/03 ARAPAHOE
0140 PM LONE TREE CO 2.75 INCH HAIL
08/18/03 DOUGLAS
0138 PM AURORA CO 0.75 INCH HAIL
08/18/03 ARAPAHOE
0117 PM 2 NE GLENHAVEN CO 1.00 INCH HAIL
08/18/03 LARIMER
BENTONThe Cheyenne radar (KCYS), 77 km away, was scanning. The volume nearest the first event began at 22:29 UTC.
1 lightning. Local standard time, as filed.
Lighting hit a truck as a family was travelling along U.S. Highway 34 near Fort Collins. The bolt struck the antenna and the stalled the truck, stranding the family.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2003Every state in 2003This day in weather historyWarnings in Colorado, August 2003
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: 5374741.