Thunderstorms developed during the afternoon in Central Iowa along an old stationary front in hot and humid conditions. The thunderstorms moved into Eastern Iowa and became severe.
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 DVN wrote it up.
Thunderstorms developed during the afternoon in Central Iowa along an old stationary front in hot and humid conditions. The thunderstorms moved into Eastern Iowa and became severe. Winds of 50 mph were common along the main gust front breaking many small limbs from trees. The storms reached maximum intensity between 1700 and 1800 CST in Eastern Iowa where a downburst caused severe damage to the NWS office in Davenport, Iowa. Once the storms crossed the Mississippi River, they quickly lost strength due to the setting sun and moving away from the better moisture convergence along the old front.
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 20, 2:30 PM CST, 3 hours 5 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 330 PM CDT WED AUG 20 2003 SHORT TERM FORECAST CHALLENGE CENTERS ON SEVERE POTENTIAL THIS EVENING WITH WW 875 ALREADY OUT. CONVECTIVE TEMPERATURES IN MID 90S HAVE BEEN REACHED WITH VISIBLE SATELLITE SHOWING CU FIELD FROM CID THROUGH FFL WEST TO SOUTH CENTRAL IA BEHIND WEAK WARM FRONT ANALYZED FROM ABOUT KBRL TO KEST AT 18Z EXTENDING NW TO COLD FRONT IN HIGH PLAINS ACROSS CENTRAL DAKOTAS TO NEB PANHANDLE. DEVELOPING TSRA UPSTREAM IN S CENTRAL IA OCCURRING AHEAD OF TAIL END OF MN H5 SHORTWAVE ENERGY. SEPARATE VORT MAX IN S CENTRAL KS THAT DID NOT INITIALIZE WELL IN 12Z MODELS...SHOULD CONTRIBUTE ADDITIONAL FORCING FOR TSRA AS IT ROTATES E-NE THIS EVENING AND INTERACTS WITH BOUNDARIES...INTIALLY SOUTH OF I-80. WITH WIDESPREAD DEWPOINTS IN MID TO UPPER 70S AND TEMPS IN 90S TO 100...LI/S RANGING FROM -8 TO -10 AND SURFACE CAPES FROM 3000 TO 5000 J/KG NW TO SE...ATMOSPHERE IS DEFINITELY UNSTABLE ACROSS CWFA. NEARLY UNIDIRECTIONAL WIND PROFILES AND HIGH FREEZING LEVELS WILL SUPPORT MAINLY SEVERE WIND THREAT WITH BOWING TSRA COMPLEXES AND LESSER THREAT OF LOW END SEVERE HAIL...AS INDICATED SO FAR BY SEVERE REPORTS FROM DMX THIS AFTERNOON. STORMS SHOULD BE MOSTLY BEFORE MIDNIGHT AS MAIN SHORTWAVE ENERGY PUSHES THROUGH. TEMPS AND POPS GRIDS CHANGED LITTLE FROM PREVIOUS FORECAST WITH HIGH DEWPOINTS LIMITING MINS TO LOW TO MID 70S AND POPS FROM 30 TO 50 FOR MAINLY EVENING. ...SHEETS .THURSDAY THROUGH NEXT WEDNESDAY... BIG QUESTION MARK FOR THURSDAY IS WILL PRECIP OCCUR. FORCING ON FRONT GETS WEAKER DURING THE DAY. COMPRESSIONAL HEATING TO HELP BOOST TEMPS DURING THE DAY ALONG WITH SLOWER MOVEMENT OF FRONT. GUIDANCE JUST LOOKS TOO COOL. FORECAST SOUNDINGS FOR ALL MODELS SHOW CONVECTIVE TEMPS OF 95 TO 100+. AS MENTIONED BEFORE... COMPRESSIONAL HEATING AND SLOWER FRONTAL MOVEMENT SHOULD ALLOW TEMPS TO CLIMB INTO THAT RANGE. THEREFORE WILL CONTINUE PRECIP THREAT BUT PUSH IT TO LATE AFTERNOON/EVENING. POSSIBILITY STILL EXITS THAT FROPA COULD BE DRY DUE TO TEMPS NOT REACHING CONVECTIVE TEMPERATURES. BEYOND THURSDAY EVENING...FORECAST LOOKS AS DRY AS DUST. FRONT TO STALL AND WASH OUT JUST SOUTH OF CWFA BEFORE H5 RIDGE BUILDS BACK INTO THE AREA. GULF IS ALSO CLOSED FOR BUSINESS. FROPA IN THE TUES/WED TIME PERIOD TO STALL/WASH OUT OVER CWFA. MAY SEE SOME ISOLATED SHRA/TSRA...BUT THAT WOULD BE ABOUT IT. SF .DVN... IA...NONE. IL...NONE. MO...NONE.
IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007- 009-015>018-024>026-034-035-MOZ009-010-211000- HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE QUAD CITIES IA IL 550 AM CDT WED AUG 20 2003 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN IOWA... NORTHWEST AND WEST CENTRAL ILLINOIS...AND NORTHEAST MISSOURI. ...HOT TODAY...CHANCE FOR STORMS THIS EVENING THROUGH THURSDAY... .DAY ONE...TODAY AND TONIGHT... HOT AND RATHER HUMID CONDITIONS WILL BE FELT TODAY AS TEMPERATURES CLIMB INTO THE LOWER TO MIDDLE 90S. THE COMBINATION OF HEAT AND HUMIDITY WILL PUSH HEAT INDICES INTO THE 97 TO 103 DEGREE RANGE... MAINLY ALONG AND WEST OF THE MISSISSIPPI RIVER. MID AFTERNOON HEAT INDICES MAY RANGE FROM 100 TO 105 DEGREES ALONG AND WEST OF A LINE FROM IOWA CITY...TO KAHOKA MISSOURI. LOWER DEWPOINTS IN THE 60S EAST OF THE MISSISSIPPI RIVER WILL MAKE FOR LESS HUMID CONDITIONS THERE AND HEAT INDICES OF LOWER IMPACT. THERE WILL BE A CHANCE FOR A FEW THUNDERSTORMS TODAY...ESPECIALLY WEST OF THE MISSISSIPPI RIVER. THESE STORMS ARE NOT EXPECTED TO BE SEVERE AND HAVE A RELATIVELY SHORT LIFE SPAN. THEY MAY STILL BE ABLE TO PRODUCE LOCALLY HEAVY DOWNPOURS HOWEVER. AN UPPER LEVEL DISTURBANCE PUSHING ACROSS THE UPPER MIDWEST WILL CREATE A BETTER CHANCE FOR MORE SUBSTANTIAL THUNDERSTORMS LATER THIS EVENING AND TONIGHT. MOST OF THE LOCAL AREA WILL BE AT RISK OF EXPERIENCING SOME TYPE OF THUNDERSTORM ACTIVITY TONIGHT...BUT THERE WILL BE A BETTER CHANCE IN AREAS ALONG AND NORTH OF A LINE FROM SIGOURNEY...TO THE QUAD CITIES...AND TO STERLING. A FEW STORMS MAY REACH SEVERE LIMITS THIS EVENING OR TONIGHT BY PRODUCING WIND GUSTS UP TO 60 MPH...AND NICKEL SIZE HAIL. THE THUNDERSTORMS WILL ALSO BE ABLE TO PRODUCE LOCALLY HEAVY RAINFALL. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY... A COLD FRONT PUSHING INTO A VERY WARM AND HUMID AIRMASS WILL KICK OFF MORE THUNDERSTORMS ON THURSDAY. THERE IS A CHANCE THAT SOME OF THESE STORMS COULD BECOME SEVERE THURSDAY AFTERNOON AND EVENING ALONG AND AHEAD OF THE FRONT. THIS INCLUDES AREAS ALONG AND EAST OF A LINE FROM DUBUQUE...TO FAIRFIELD. IF STORMS AND THEIR ASSOCIATED CLOUDS CAN HOLD OFF LONG ENOUGH BEFORE THE FRONT PASSES LATE ON THURSDAY...HEAT AND HUMIDITY CAN BE EXPECTED TO BUILD TO POTENTIALLY DANGEROUS LEVELS. TEMPERATURES WILL CLIMB WELL INTO THE 90S...WITH HIGH TEMPERATURES POSSIBLY REACHING NEAR RECORD LEVELS IN THE UPPER 90S. AREAS WITH THE BEST CHANCE OF EXPERIENCING THIS TYPE OF HEAT ARE ALONG AND SOUTHEAST OF A LINE FROM WASHINGTON...TO THE QUAD CITIES...AND TO STERLING. HEAT INDICES WILL RANGE FROM 100 TO 105 IN THESE AREAS...WITH A GOOD CHANCE THAT THEY COULD EXCEED 105 DEGREES. A HEAT ADVISORY MAY BE NEEDED FOR PORTIONS OF THE AREA ON THURSDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED LATE THIS AFTERNOON AND TONIGHT MAINLY ALONG AND NORTH OF A LINE FROM FAIRFIELD...TO DAVENPORT...AND TO MOUNT CARROLL. SPOTTER ACTIVATION MAY ALSO BE NEEDED THURSDAY AFTERNOON IN MUCH OF THE AREA. MORE INFORMATION MAY BE OBTAINED AT THE FOLLOWING INTERNET WEB SITE: HTTP://WWW.CRH.NOAA.GOV/DVN (ALL LOWER CASE) 12
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
539 PM CDT WED AUG 20 2003
TIME(CDT) .....CITY LOCATION..... STATE ...EVENT/REMARKS...
....COUNTY LOCATION....
0539 PM ATALISSA IA 50 MPH TSTM GUST
08/20/03 MUSCATINE REPORTED BY STORM
SPOTTER.PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
549 PM CDT WED AUG 20 2003
TIME(CDT) .....CITY LOCATION..... STATE ...EVENT/REMARKS...
....COUNTY LOCATION....
0549 PM ATALISSA IA 60 MPH TSTM GUST
08/20/03 MUSCATINE REPORTED BY STORM
SPOTTER.PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
556 PM CDT WED AUG 20 2003
TIME(CDT) .....CITY LOCATION..... STATE ...EVENT/REMARKS...
....COUNTY LOCATION....
0555 PM 4 ENE ANAMOSA IA .88 INCH HAIL
08/20/03 JONES DIME TO NICKEL HAIL.
REPORTED BY STORM
SPOTTER.PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
600 PM CDT WED AUG 20 2003
TIME(CDT) .....CITY LOCATION..... STATE ...EVENT/REMARKS...
....COUNTY LOCATION....
0600 PM MONTICELLO IA .25 INCH HAIL
08/20/03 JONES REPORTED BY STORM
SPOTTER.PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
613 PM CDT WED AUG 20 2003
TIME(CDT) .....CITY LOCATION..... STATE ...EVENT/REMARKS...
....COUNTY LOCATION....
0606 PM 5 N MUSCATINE IA 60 MPH TSTM GUST
08/20/03 MUSCATINE JCT HIGHWAY 38 AND
155TH STREET OR 4.5
MILES NORTH OF
MUSCATINE. ALSO PEA
HAIL. REPORTED BY STORM
SPOTTER.PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
631 PM CDT WED AUG 20 2003
TIME(CDT) .....CITY LOCATION..... STATE ...EVENT/REMARKS...
....COUNTY LOCATION....
0620 PM FARLEY IA 60 MPH TSTM GUST
08/20/03 DUBUQUE LIMBS DOWN WITH PEA
HAIL. REPORTED BY
EMERGENCY MANAGEMENT.
0622 PM EPWORTH IA 60 MPH TSTM GUST
08/20/03 DUBUQUE LIMBS DOWN WITH PEA
HAIL. REPORTED BY
EMERGENCY MANAGEMENT.
0625 PM PEOSTA IA 60 MPH TSTM GUST
08/20/03 DUBUQUE LIMBS DOWN WITH PEA
HAIL. REPORTED BY
EMERGENCY MANAGEMENT.
0626 PM LOST NATION IA .5 INCH HAIL
08/20/03 CLINTON DIME SIZE HAIL AND 0.50
INCH RAIN. REPORTED BY
EMERGENCY MANAGEMENT.The Quad Cities radar (KDVN), 45 km away, was scanning. The volume nearest the first event began at 23:33 UTC.
4 thunderstorm wind. Local standard time, as filed.
Event occurred with the gust front. 6 inch diameter limbs down with gravel blown off the road.
Tree limbs down on power lines.
Tree limbs down on power lines.
Measured gust by Co-op
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2003Every state in 2003This day in weather historyWarnings in Illinois, 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: 5374327, 5374328, 5374329, 5374330.