A weak upper level disturbance provided sufficient lift for thunderstorms to develop in the hot and humid conditions across Southeast Iowa and West Central Illinois during the afternoon and early evening.
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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 DVN wrote it up.
A weak upper level disturbance provided sufficient lift for thunderstorms to develop in the hot and humid conditions across Southeast Iowa and West Central Illinois during the afternoon and early evening.
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 Quad Cities, IA wrote its last area forecast discussion before the first event at Aug 28, 12:55 PM CST, 35 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 155 PM CDT THU AUG 28 2003 .OVERVIEW...AMAZING HOW YE OLDE CONCEPTUAL MODELS ALWAYS WORK VORT MAX NEAR OMA AT 18Z ALONG TRIPLE POINT CREATING GENESIS OF CONVECTION IN SC IA AND CENTRAL MISSOURI. NOWCAST TOOLS SUPPORT SOUTHERN 1/2 TO 2/3 AREA TO RECEIVE LOTS OF TSRA/SHRA WITH SOME SEVERE NEXT 6-12 HOURS WITH LOCALLY HEAVY RAINS UP TO 3 INCHES. ON LARGER SCALE... STRONG COLD FRONT NOW MOVING SOUTHEAST AT 20-25 MPH TO PASS BY MORNING BRINGING REFRESHING COOLER AND LESS HUMID AIR. ...PRECIPITATION TONIGHT WITH SEVERE AND HEAVY RAIN POTENTIAL NEAR TERM CONCERN...THEN COOL OFF BEHIND FRONT AND QUIET WEATHER... .DIAGNOSIS & DAYS 1-3 (FRI-SUN)...LATEST MODELS NOW MUCH HEAVIER ON QPF WITH 1-3 INCH AMOUNTS SUGGESTED AS HAS BEEN ANTICIPATED AS THEY CAPTURE TRIPLE POINT VORT MAX. PLAN TO USE MAINLY NOWCAST TOOLS NEXT 6 HOURS WITH BEST SOLUTION APPEARS TO BE ETA WITH SOME INPUTS FROM GFS-AVN AND UKMET. THUS...CATEGORICAL MOST OR ALL AREAS TONIGHT WITH SEVERE VERBIAGE. EXPECT SPC TO PROBABLY PUT WATCH BOX OUT LATER THIS PM AS CONVECTION INTENSIFIES AND COALESCES. BLEP VALUES THROUGH 8 PM SUGGEST 60-70 MPH WINDS POSSIBLE...THEN DIMINISHING BELOW 60 MPH AROUND MIDNIGHT. PRECIPITAL WATER AMOUNTS OF 2 INCHES GUARANTEE VERY HEAVY RAIN WITH STORMS NEXT SEVERE HOURS...SO CANT RULE OUT SOME LOCALIZED FLOODING EVEN WITH DRY GROUND. STRENGTH OF COLD AIR WILL DISCARD MOST OF GFS SUGGESTION OF WAVE FOR LOTS OF RAIN SOUTH TOMORROW. STILL PLAN FOR SOME MORNING POPS WORDING THERE...BUT CLOUDS AND PRECIPITATION SHOULD BE WELL SOUTH OF AREA BY LATE MORNING. WILL GO WITH BREEZY AND LESS HUMID VERBIAGE TOMORROW WITH GOOD PM SUNSHINE...CAA AND DECENT GRADIENT FOR MAX MIXING OF MOMENTUM TO SURFACE. WILL BE QUITE A CHANGE. THEN QUIET WEATHER STILL SUGGESTED BY ALL SOLUTIONS WITH SFC HIGH OVERHEAD. TEMPS ON HIGH SIDE GUIDANCE FOR HIGHS BY SUNDAY WITH LOWS ON LOW SIDE AS DEWPOINTS WILL BE WELL INTO 40S...NICE AUTUMN WEATHER. .EXTENDED (MON-THU)...SLOW WARMUP TO START BY TUESDAY. PLAN TO KEEP DRY FOR NOW AS STILL NO COHERENT MOISTURE OR TRIGGER. A NICE SPELL OF EARLY AUTUMN WEATHER. .DVN... IA...NONE. IL...NONE. MO...NONE. NICHOLS
IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007- 009-015>018-024>026-034-035-MOZ009-010-290915- HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE QUAD CITIES IA IL 453 AM CDT THU AUG 28 2003 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN IOWA... NORTHWEST AND WEST CENTRAL ILLINOIS...AND NORTHEAST MISSOURI. .DAY ONE...TODAY AND TONIGHT... HOT AND HUMID CONDITIONS WILL AGAIN BE SEEN ACROSS THE AREA. HEAT INDICES LATE THIS AFTERNOON ARE EXPECTED TO CLIMB INTO THE 95 TO 100 DEGREE RANGE. TONIGHT A STRONG COLD FRONT IS FORECAST TO MOVE THROUGH THE REGION. THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG AND AHEAD OF THE FRONT AND CONTINUE THROUGH MUCH OF THE NIGHT. MOST THUNDERSTORMS SHOULD HAVE WIND GUSTS IN THE 35 TO 45 MPH RANGE. HOWEVER THE STRONGEST STORMS MAY PRODUCE WIND GUSTS TO 60 MPH AND HAIL UP TO ONE INCH. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY... THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. FRIDAY MORNING...ANY LINGERING RAIN AND THUNDERSTORMS SOUTH OF A SIGOURNEY TO KEWANEE LINE WILL END BY MID DAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED LATE THIS AFTERNOON AND EVENING ACROSS EASTERN IOWA. SF
The Quad Cities radar (KDVN), 144 km away, was scanning. The volume nearest the first event began at 19:31 UTC.
2 thunderstorm wind. Local standard time, as filed.
Large 15 inch diameter limb down on Olive Street.
Outbuildings and a silo damaged.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2003Every state in 2003This day in weather historyWarnings in Iowa, 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: 5374202, 5374203.