Scattered thunderstorms developed ahead of an upper level disturbance in a semi-moist atmosphere. 50 inches occurred in a 15 to 30 minute time period.
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.
Scattered thunderstorms developed ahead of an upper level disturbance in a semi-moist atmosphere. Due to the slow movement of the storms, rainfall amounts of 1.25 to 1.50 inches occurred in a 15 to 30 minute time period.
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 Jul 16, 2:35 AM CST, 9 hours 49 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 335 AM CDT FRI JUL 16 2004 .SYNOPSIS...SURFACE PATTERN INTERESTING THIS MORNING WITH A SURFACE LOW OVER EASTERN NEBRASKA...WITH A WARM FRONT EXTENDING FROM IT TO SOUTH CENTRAL MISSOURI. SIGNIFICANT MCS IN PROGRESS JUST NORTH OF THE FRONT OVER SOUTHWEST IA AND NORTHWEST MO...GRADUALLY PROGRESSING SOUTHEAST. THIS MCS ACTIVITY IS IN AN AREA OF WARM AIR ADVECTION... AND SOME SHOWERS CAN BE OBSERVED NORTHEAST OF THE MCS INTO THE SOUTHWEST PORTIONS OF THE CWA. AN INVERTED TROUGH EXTENDS NORTHEAST FROM THE LOW INTO NORTHWEST WI...WITH SOME SCATTERED ACTIVITY ALONG IT ALSO. THIS ACTIVITY APPEARS TO BE SUPPORTED BY A VORT MAX DROPPING SOUTHEAST ACROSS MN. && .SHORT TERM (TODAY AND TONIGHT)...THE SHORTWAVE DROPPING SOUTHEAST ACROSS MN THIS MORNING WILL MOVE INTO THE CWA AROUND LATE MORNING AND EARLY AFTERNOON...AS WELL AS THE INVERTED TROUGH ALSO PUSHING INTO THE AREA. SO...SEE NO REASON WHY SOME SHOWERS AND THUNDERSTORMS SHOULDNT POP ACROSS THE CWA DURING THE DAY...AND HAVE RAISED POPS INTO THE HIGH CHANCE CATEGORY. SOME CONVERGENCE LINGERS ACROSS THE AREA INTO THE EVENING HOURS...AND ANOTHER LOBE OF VORTICITY RUNS SOUTHEAST ACROSS THE AREA. SO...THINK SOME CONVECTION MAY LINGERING INTO THE EVENING HOURS ACROSS THE CWA. SIGNALS NOT QUITE AS STRONG... SO HAVE KEPT CHANCE POPS LOW...AND ONLY IN THE EVENING. TEMPERATURES TODAY SHOULD BE KEPT DOWN SOMEWHAT WITH INCREASED CLOUD COVER AND PRECIP CHANCES...SO HAVE KEPT VALUES CLOSER TO THE MAV/ETA VALUES RATHER THAN THE WARMER FWC. TONIGHT HARD TO ARGUE WITH GOING FCST... THOUGH RAISED THEM A LITTLE ACROSS THE SOUTHERN PORTIONS OF THE CWA. ..LE.. && .LONGER TERM (SATURDAY THROUGH NEXT THURSDAY)...SHORT RANGE MODELS REASONABLY SIMILAR IN HANDLING THE SYNOPTIC SCALE TRENDS OF MAINTAINING UPPER RIDGE OVER THE ROCKIES THIS WEEKEND...WITH DIGGING TROUGH OVER THE OH AND TN RVR VALLEYS. THUS LOOKS LIKE NORTHWEST FLOW/BENIGN WX REGIME TO CONTINUE INTO EARLY NEXT WEEK... BEFORE MEDIUM RANGE MODEL ENSEMBLE SUGGESTS ENOUGH CANADIAN WAVE ENERGY PUMMELS DOWN UPPER RIDGE INTO MORE OF A ZONAL FLOW PATTERN ACRS THE NORTHERN THIRD OF THE CONUS BY MID NEXT WEEK. AS BAROCLINICITY GETS LAID OUT IN GENERAL WEST-TO-EAST ALIGNMENT ACRS THE UPPER MIDWEST IN STORM TRACK IN THIS TIME FRAME NEXT WEEK... SHOULD MEAN MORE OF AN ACTIVE PATTERN FROM TUE THRU NEXT THU. SOME THERMAL RIDGE DRAW UP ACRS THE AREA OUT OF THE SOUTHERN PLAINS WILL ALSO MAKE FOR A MORE SEASONABLE JULY TEMP SCENARIO WITH READINGS AT LEAST IN THE MID TO UPPER 80S. BACK TO SATURDAY...INCREASING NORTH-NORTHEAST FLOW AT H85 MB TO TAP INTO LLVL COOL POOL OVER THE NORTHERN GRT LKS...WITH +10 C VALUES GETTING DRAWN CLOSE TO OR ACRS THE NORTHERN CWA. LOOKS LIKE ANOTHER ROUND OF GRT LKS/BACKDOOR COLD FRONT AFFECT GETTING PUSHES SOUTHWEST ACRS THE DVN CWA FROM SFC RIDGE BUILDING ACRS THE U.P. OF MI...WILL KEEP MUCH OF THE CWA IN THE 70S. STEEP LLVL LAPSE RATES AND CU RULE SUGGEST CU TO BUILD TO BROKEN LEVELS AS WELL IN THE AFTERNOON... ANOTHER FACTOR LEADING TO A SEASONABLY COOL DAY. AS SFC RIDGE CENTER BUILDS SOUTH TOWARD THE LOCAL AREA SAT NIGHT INTO SUNDAY MORNING...IF CI STREAMING SOUTH IN NORTHWEST FLOW ALOFT CAN BE KEPT TO A MINIMUM ...MUCH OF THE CWA TO DIP INTO THE 50S FOR LOWS BY SUNDAY MORNING WITH EVEN A FEW SITES POTENTIALLY CLOSING IN ON RECORD LEVELS IN THE MID 50S. RIDGE CENTER AND INHERENT WEAK MIXING MAY NOT ALLOW TEMPS TO REACH MUCH ABOVE 80 ON SUNDAY...EVEN WITH MORE INSOLATION EXPECTED IN FULL COLUMN SUBSIDENCE/DRYING. ..12.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && LE/12
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE QUAD CITIES IA IL 500 AM CDT FRI JUL 16 2004 IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007- 009-015>018-024>026-034-035-MOZ009-010-171000- 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- 500 AM CDT FRI JUL 16 2004 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST... EAST CENTRAL...AND SOUTHEAST IOWA...NORTHWEST...NORTH CENTRAL... AND WEST CENTRAL ILLINOIS...AND NORTHEAST MISSOURI. .DAY ONE...TODAY AND TONIGHT SCATTERED THUNDERSTORMS ARE EXPECTED ACROSS THE AREA TODAY INTO THIS EVENING. A WEAK SURFACE FRONT WILL DROP SOUTHEAST TO LAY ACROSS THE AREA TODAY...AS AN UPPER LEVEL WAVE MOVES ACROSS THE AREA AT THE SAME TIME. THE ATMOSPHERE IS EXPECTED TO BE MODERATELY UNSTABLE...BUT OTHER FEATURES ARE NOT QUITE AS FAVORABLE FOR STRONG THUNDERSTORMS. SO...THERE IS A SLIGHT RISK OF SEVERE WEATHER. STORMS THAT BECOME STRONG ENOUGH MAY PRODUCE DAMAGING WINDS...FREQUENT DANGEROUS LIGHTNING AND LOCALLY HEAVY RAIN. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY AN ACTIVE STORM TRACK WILL SET UP ACROSS THE UPPER MIDWEST BY THE MIDDLE PART OF NEXT WEEK. ALTHOUGH THE BEST CHANCE OF STRONG TO SEVERE THUNDERSTORMS WILL OCCUR TO THE NORTH OF THE AREA IN MINNESOTA AND WISCONSIN...THERE WILL STILL BE THE CHANCE OF SOME STRONG STORMS IN THE LOCAL AREA FROM TUESDAY THROUGH THURSDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED TODAY OR TONIGHT. LE/12
The Quad Cities radar (KDVN), 61 km away, was scanning. The volume nearest the first event began at 18:23 UTC.
5 thunderstorm wind, 2 hail. Local standard time, as filed.
Stop signs blown down with power poles downed.
Also estimated 43 knot (50 mph) winds.
Downburst dropped 12 inch diameter limbs in Wapsipinicon Park with numerous other 3-4 inch limbs down in town. A highway sign was also downed with 1.25 inches of rain in 30 minutes.
Also estimated 48 knot (55 mph) winds.
Winds estimated at 43-52 knots (50-60 mph) for about 15 minutes with numerous limbs down.
Large pine tree down on a farm house with a power line down.
Large trees down across a road blocking traffic with several trees down on adjacent property.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2004Every state in 2004This day in weather historyWarnings in Iowa, July 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: 5424303, 5424300, 5424301, 5424302, 5424306, 5424304, 5424305.