An upper level disturbance allowed thunderstorms to develop during the heat of the day, producing isolated severe thunderstorms.
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.
An upper level disturbance allowed thunderstorms to develop during the heat of the day, producing isolated severe thunderstorms.
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 May 9, 1:45 PM CST, 3 hours 20 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 245 PM CDT SUN MAY 9 2004 .SYNOPSIS...WARM FRONT HAS LIFTED WELL NORTH OF CWA...REACHING FROM EASTERN SD SURFACE LOW TO SW LOWER MI. LAST NIGHTS CONVECTIVE COMPLEXES UPSTREAM OVER KS...NEB...AND WESTERN IA THAT PRODUCED UP TO 2 TO 3 INCH DIAMETER HAIL HAS LEFT AN MCV NOW JUST NORTH OF OTM. ANOTHER STRONGER MCV PRODUCED SHOWERS AND THUNDERSTORMS OVER DBQ TO FREEPORT AND IS NOW PRODUCING SEVERE STORMS ALONG WESTERN SHORES LAKE MI. AT UPPER LEVELS... ZONAL FLOW CONTINUES WITH SHORTWAVE MOVING THROUGH CWA THIS AFTERNOON. BASE OF LONGER WAVE TROUGH MOVING INTO DAKOTAS WILL HELP PUSH THE SURFACE COLD FRONT BACK THROUGH EARLY WEEK. && .SHORT TERM...(TONIGHT)...IMMEDIATE CONCERN CENTERS ON CONVECTIVE POTENTIAL THIS AFTERNOON INTO THIS EVENING. OVER PAST HOUR THUNDERSTORMS HAVE RAPIDLY DEVELOPED AT NORTHERN EDGE OF MAX INSTABILITY OVER SE IA WHERE SB CAPES IN 2 TO 3 KJ/KG RANGE. THIS IS AHEAD OF MCV PUSHING TOWARD AREA. WITH UNIDIRECTIONAL WIND PROFILE AND ONLY WEAK SURFACE BOUNDARIES...LARGE HAIL MAIN CONCERN WITH SECONDARY CONCERN OF DAMAGING STRAIGHT LINE WINDS. LOCAL TECHNIQUES SHOW POTENTIAL FOR HAIL UP TO 2.2 INCHES AND WIND GUSTS UP TO 78 KTS. IN FORECAST...WILL HAVE SCATTERED SHOWERS AND THUNDERSTORMS GOING UNTIL EVENING...THEN FOCUS LATE TONIGHT WHEN A COMPLEX MAY DEVELOP MOVE WELL OUT AHEAD OF APPROACHING FRONT. ...DLS... && .LONG TERM...(MONDAY THROUGH SUNDAY) COLD FRONT TO APPROACH REGION DURING THE DAY WITH AMOUNT OF CLOUDS AND PRECIPITATION AND IMPACTS ON TEMPS MAIN LINGERING ISSUE. MODELS VARY AND BASED ON SUGGESTED FORCING WENT WITH PARTLY CLOUDY SE EXCEPT FAR NW WITH HIGH CHANCE POPS BUT LIKELY POPS STILL PLAUSIBLE FOR NIGHT FOLKS TO CONSIDER. THUS NEAR GUIDANCE NW AND SLIGHTLY ABOVE ON TEMPS SE WITH MORE SUN. STILL LOOKS LIKE MODERATE INSTABILITY (CAPE 1000-1500 J/KG) AND FORCING FOR SHOWERS AND STORMS AND A SOME SEVERE WITH LARGE HAIL UP TO THE SIZE OF QUARTERS MAIN ISSUE PER LOCAL CALCULATIONS. ALL IN ALL A LOW TO MODERATE END SEVERE WEATHER POTENTIAL...IF THE FRONT DURING THE AFTERNOON GETS IF ENOUGH HEATING AND WEAK WAVE FORMS THOUGH...MORE SIGNIFICANT SEVERE WX COULD OCCUR WHICH CAN/T BE RULED OUT. NEXT MAJOR CHALLENGE IS WHERE FRONT STALLS OUT...MODELS VARY QUITE A BIT AND WENT WITH CLIMATOLOGY AND MAJORITY OF GUIDANCE (ETA WAS MUCH FURTHER NORTH) FOR FRONT TO STALL JUST SOUTH OF I-80. KEPT HIGH CHANCE POPS OVERNIGHT INTO TUESDAY WITH DECENT 10+ DEGREE GRADIENT ACROSS FORECAST AREA THOUGH WEAKER EAST WINDS WILL NOT PRODUCE AS STRONG A LAKE ENHANCED COOLING AS A COUPLE DAYS AGO. THEN WARM WITH CHANCE OF A STORM TIL LATE THURSDAY WITH STRONG COLD FRONT. APPEARS ENERGY TO NOT COME OUT IN ONE LARGE SEGMENT WHICH MAY NOT PRODUCE AS A MUCH A HIGH END EVENT...BUT STILL WOULD PRODUCE SIGNIFICANT SEVERE WEATHER EPISODE(S)...BELIEVE DEFINITELY SHOULD BE ABLE TO DETERMINE RISKS BETTER BY TOMORROW...ESPECIALLY FOR TORNADO POTENTIAL. FRONT NOW DELAYED PASSING TIL FRIDAY AND TRIED TO ADJUST IN FORECAST AS MUCH AS POSSIBLE FOR NOW. STILL LOOKS LIKE MAINLY 60S FOR HIGHS AND 40S FOR LOWS THIS NEXT WEEKEND. ...NICHOLS... && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && SHEETS/NICHOLS
HAZARDOUS WEATHER OUTLOOK...CORRECTION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 520 AM CDT SUN MAY 9 2004 CORRECTED TODAY HEADING IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007-009- 015>018-024>026-034-035-MOZ009-010-101000- BENTON IA-BUCHANAN IA-BUREAU IL-CARROLL IL-CEDAR IA-CLARK MO-CLINTON IA- DELAWARE IA-DES MOINES IA-DUBUQUE IA-HANCOCK IL-HENDERSON IL-HENRY IA- HENRY IL-IOWA IA-JACKSON IA-JEFFERSON IA-JO DAVIESS IL-JOHNSON IA- JONES IA-KEOKUK IA-LEE IA-LINN IA-LOUISA IA-MCDONOUGH IL-MERCER IL- MUSCATINE IA-PUTNAM IL-ROCK ISLAND IL-SCOTLAND MO-SCOTT IA- STEPHENSON IL-VAN BUREN IA-WARREN IL-WASHINGTON IA-WHITESIDE IL- 520 AM CDT SUN MAY 9 2004 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST IOWA... EAST CENTRAL IOWA...SOUTHEAST IOWA...NORTHWEST ILLINOIS...NORTH CENTRAL ILLINOIS...WEST CENTRAL ILLINOIS AND NORTHEAST MISSOURI. .DAY ONE...TODAY AND TONIGHT ISOLATED THUNDERSTORMS OVER EASTERN IOWA AND NORTHWEST ILLINOIS WILL END EARLY THIS MORNING. SMALL HAIL IS POSSIBLE WITH STRONGER STORMS. A DISTURBANCE OVER CENTRAL IOWA WILL BRING THE POSSIBILITY OF A FEW ISOLATED THUNDERSTORMS DURING THE AFTERNOON. IF THESE THUNDERSTORMS DEVELOP...THEY WILL HAVE THE POTENTIAL TO PRODUCE HAIL AND GUSTY WINDS. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SUNDAY THE ACTIVE WEATHER PATTERN WILL PERSIST THROUGH THURSDAY NIGHT. ANOTHER ROUND OF THUNDERSTORMS WILL MOVE THROUGH THE AREA EARLY MONDAY MORNING THROUGH MONDAY NIGHT. AT THIS TIME...THE MAIN THREAT APPEARS TO BE LARGE HAIL AND HEAVY RAIN. THUNDERSTORMS WILL HAVE THE POTENTIAL TO MOVE OVER THE SAME AREAS SEVERAL TIMES MONDAY NIGHT...POSSIBLY BRINGING ADDITIONAL RAINFALL TOTALS AROUND 2 INCHES. SEVERAL MORE ROUNDS OF STRONG TO SEVERE THUNDERSTORMS CAN BE EXPECTED TUESDAY THROUGH THURSDAY NIGHT. THURSDAY AFTERNOON AND THURSDAY NIGHT APPEAR TO BE THE GREATEST RISK OF WIDESPREAD STRONG THUNDERSTORMS. FRIDAY MORNING...A STRONG COLD FRONT IS EXPECTED TO SWEEP THROUGH THE PLAINS... ENDING THE PROLONGED PERIOD OF STORMY WEATHER. DUE TO THE MODERATE TO HEAVY RAIN TOTALS EXPECTED THIS WEEK...AREA RIVERS WILL LIKELY EXPERIENCE GENERAL RISES. EMERGENCY MANAGERS SHOULD LISTEN TO LATER FORECASTS REGARDING THE POTENTIAL FOR SEVERE WEATHER THROUGH MID WEEK. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION NOT EXPECTED TODAY OR TONIGHT. ERVIN
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
350 PM CDT SUN MAY 09 2004
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION...ST.. ...SOURCE....
..REMARKS..
0402 AM TSTM WND GST WILTON 41.59N 91.02W
05/07/2004 50 MPH MUSCATINE IA TRAINED SPOTTER
0402 AM HAIL WILTON 41.59N 91.02W
05/07/2004 0.75 INCH MUSCATINE IA TRAINED SPOTTER
&&
SKPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
449 PM CDT SUN MAY 09 2004
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION...ST.. ...SOURCE....
..REMARKS..
0448 PM TSTM WND GST ELIZABETH 42.32N 90.22W
05/09/2004 50 MPH JO DAVIESS IL LAW ENFORCEMENT
&&
SKPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
520 PM CDT SUN MAY 09 2004
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION...ST.. ...SOURCE....
..REMARKS..
0516 PM HAIL LENA 42.38N 89.83W
05/09/2004 0.25 INCH STEPHENSON IL LAW ENFORCEMENT
0510 PM TSTM WND GST PEOSTA 42.45N 90.85W
05/09/2004 0 MPH DUBUQUE IA TRAINED SPOTTER
50 TO 60 MPH WIND REPORTED ON THE SOUTH SIDE OF PEOSTA
&&
DLFPRELIMINARY LOCAL STORM REPORT ... CORRECTION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
522 PM CDT SUN MAY 09 2004
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION...ST.. ...SOURCE....
..REMARKS..
0510 PM TSTM WND GST PEOSTA 42.45N 90.85W
05/09/2004 60 MPH DUBUQUE IA TRAINED SPOTTER
50 TO 60 MPH WIND REPORTED ON THE SOUTH SIDE OF PEOSTA
&&
DLFPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
528 PM CDT SUN MAY 09 2004
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION...ST.. ...SOURCE....
..REMARKS..
0523 PM HAIL DUBUQUE 42.50N 90.69W
05/09/2004 0.25 INCH DUBUQUE IA EMERGENCY MNGR
0520 PM TSTM WND GST KEY WEST 42.45N 90.68W
05/09/2004 60 MPH DUBUQUE IA EMERGENCY MNGR
0514 PM NON-TSTM WND DMG DUBUQUE 42.50N 90.69W
05/09/2004 DUBUQUE IA EMERGENCY MNGR
SHINGLES BLOWN OFF OF A ROOF ON UNIVERSAL DRIVE
&&
DLFPRELIMINARY LOCAL STORM REPORT ... CORRECTION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
536 PM CDT SUN MAY 09 2004
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION...ST.. ...SOURCE....
..REMARKS..
0514 PM TSTM WND DMG DUBUQUE 42.50N 90.69W
05/09/2004 DUBUQUE IA EMERGENCY MNGR
SHINGLES BLOWN OFF OF A ROOF ON UNIVERSAL DRIVE
&&
DLFThe Quad Cities radar (KDVN), 97 km away, was scanning. The volume nearest the first event began at 23:05 UTC.
1 thunderstorm wind. Local standard time, as filed.
Lots of branches down with corn flattened in the field.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2004Every state in 2004This day in weather historyWarnings in Illinois, May 2004
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: 5405753.