An intense spring storm system brought sustained winds of 27-33 knots (30-40) mph with gusts over 43 knots (50 mph) to Eastern Iowa, Northern Illinois, and far Northeast Missouri. At Illinois Valley Regional Airport (KVYS) in Peru, Illinois, a wind gust of 54 knots (62 mph) was recorded.
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 episode as NWS DVN wrote it up.
An intense spring storm system brought sustained winds of 27-33 knots (30-40) mph with gusts over 43 knots (50 mph) to Eastern Iowa, Northern Illinois, and far Northeast Missouri. At Illinois Valley Regional Airport (KVYS) in Peru, Illinois, a wind gust of 54 knots (62 mph) was recorded. In Whiteside County Illinois, numerous power lines, limbs and some trees were downed. At one point over 5,000 people in Northwest Illinois were without power.
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 11, 4:00 AM CST, 4 hours 10 minutes earlier.
AREA FORECAST DISCUSSION...CORRECTED TO ADD WIND HIGHLIGHTS NATIONAL WEATHER SERVICE QUAD CITIES IA IL 500 AM CDT SUN MAY 11 2003 LATEST SURFACE ANALYSIS SHOWS DEEP CYCLONE (985 MBS) OVER WESTERN WI WITH CENTRAL PRESSURE DROPPING ABOUT 2 MBS/HR. DEEPENING TREND EXPECTED TO SLOW AND EVENTUALLY COME TO HALT THIS MORNING AS SYSTEM BECOMES VERTICALLY STACKED AND OCCLUDES. REGIONAL RADAR LOOP SHOWS RAIN ASSOCIATED WITH DEFORMATION ZONE INTO FAR NORTHERN IA ATTIM. ISALLOBARIC MAX PUSHED THROUGH AROUND MIDNIGHT PRODUCING WIND GUSTS OF 40-45 KTS. SECOND SURGE NOTED AT PRESENT TIME WITH TIGHTENING PRESSURE GRADIENT PRODUCING VERY WINDY CONDITIONS WITH SEVERAL SITES AT/ABOVE WIND ADVISORY CRITERIA (SUSTAINED 30 MPH FOR 1 HR OR GUSTS OF 45 MPH OR GREATER FOR ANY DURATION). MAIN CHALLENGES RESIDE WITH WINDS...AND PCPN CHCS NEXT 12-18RS WITH BACKLASH. BEYOND...CONCERNS WITH PCPN CHANCES MIDWEEK. NEAR TERM...DEEPENING CYCLONE WILL MOVE INTO THE GREAT LAKES AND BECOME VERTICALLY STACKED...ESSENTIALLY SLOWING FORWARD SPEED WITH FAR NORTHERN ZONES ON THE EDGE OF DEFORMATION BAND. WEAK SHORTWAVE ALSO PROGGED TO DROP DOWN BACKSIDE OF SYSTEM AND ACROSS THE NORTH...SO WILL PLACE HIGH CHANCE POPS IN THE NORTH TAPERING OFF AS YOU HEAD SOUTH. DMX/DVN RADARS SHOW INCREASE IN BANDING OF WEAK RETURNS NORTH OF HWY 34. OVERALL...HIGH POP/LOW QPF EVENT. FEEL BEST WORDING WILL BE WITH OCCASIONAL DRIZZLE/LIGHT RAIN NORTH...WITH MAINLY DRIZZLE IN THE SOUTH. CLOUDS AND LIGHT PCPN TO TEMPER MAXES AND UNDERCUT GUIDANCE BY A FEW DEGS. NEXT CONCERN IS WITH WIND. INITIAL SURGE OF ADVISORY CRITERIA WINDS BLASTED THROUGH AROUND MIDNIGHT WITH ISALLOBARIC MAX...NOW SEEING OVERALL WIND FIELD INCREASE DUE TO TIGHTENING PRESSURE GRADIENT. VERY IMPRESSIVE HEIGHT FALL CENTER OF OVER 200 M IN WESTERN WI...MORE TYPICAL OF LATE WINTER/EARLY SPRING. MODELS SHOW PRESSURE GRADIENT MAXIMIZED ACROSS STATE OF IA THIS MORNING AT ROUGHLY 18 MBS USING RULE OF MAXIMUM WIND (GUSTS) OF 10 MPH FOR EVERY 4 MBS MSLP GRADIENT THIS SUGGESTS MAX GUSTS JUST OVER 40 KTS...WHICH LOOKS TO BE VERIFYING PRETTY WELL...AND HAVE ALREADY HOISTED A WIND ADVISORY WHICH IS IN EFFECT FOR TODAY. SOME CONCERNS THAT A FEW LOCATIONS COULD PUSH WARNING CRITERIA. TONIGHT...VERTICALLY STACKED SYSTEM MOVES SLOWLY EAST THROUGH THE GREAT LAKES. ANY DRIZZLE OR LIGHT RAIN LOOKS TO BE END IN THE EVENING AS WEAK SHORTWAVE ON BACKSIDE OF SYSTEM PULLS EAST. SURFACE RIDGING BUILDS INTO WESTERN IA WITH FLOW BECOMING BIT MORE ANTICYCLONIC WEST OF THE MISSISSIPPI. MODELS SHOW DEEP COLUMN DRYING INTO WESTERN 1/3RD OR SO BY 12Z MON. WILL BE OPTIMISTIC AND GO WITH PARTIAL CLEARING FOR NOW...EXCEPT EAST WHERE LLVL CYCLONIC FLOW SHOULD KEEP CLOUDS AROUND FOR MUCH OF THE NIGHT. MIN TEMPS CHALLENGING WITH CLOUDS TRENDS DIFFICULT...AND AMPLE MIXING IN BL WITH WINDS STAYING UP IN RANGE OF 10-20 MPH OR SO. POTENTIAL TO BE COLDER IN THE WEST AND WARMER IN THE EAST. MUCH NEEDED REST FROM ACTIVE PATTERN IN STORE TO START THE WORK WEEK. ETA...UKMET AND GFS INDICATE NEXT CHANCE OF RAIN LATE TUE THOUGH MIDWEEK WITH CONVECTION DEVELOPING IN PLAINS ON NOSE OF STRONG WARM ADVECTION. ACTIVITY WILL BLEED SOUTHEAST WITH MEAN STEERING FLOW FROM THE NORTHWEST...HOWEVER ATMOSPHERE FAIRLY STABLE...SO EXPECT STRATIFICATION AND MAINLY JUST RAIN INTO WED...THOUGH CAN/T RULE OUT SOME THUNDER WITH ELEVATED INSTABILITY WED AFTERNOON/NIGHT AS FRONTAL ZONE FIRMS UP TO OUR SOUTH. WENT AHEAD AND INTRODUCED POPS TUE NIGHT THROUGH WED SINCE ALL MODELS ARE POINTING TOWARD THIS SCENARIO...WITH MAIN DIFFERENCE WITH TIMING/SATURATION AS LLVL FLOW WILL BE FROM THE EAST AND NORTHEAST. COORDINATED WITH DMX...LOT...ILX...THANX DVN... IA...WIND ADVISORY TODAY EASTERN IOWA. IL...WIND ADVISORY TODAY NORTHWEST AND WEST CENTRAL ILLINOIS. MO...WIND ADVISORY TODAY EXTREME NORTHEAST MISSOURI. 05
IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007- 009-015>018-024>026-034-035-MOZ009-010-121000- HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE QUAD CITIES IA IL 543 AM CDT SUN MAY 11 2003 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN IOWA... NORTHWEST AND WEST CENTRAL ILLINOIS...AND NORTHEAST MISSOURI. .DAY ONE...TODAY AND TONIGHT AN INTENSE LOW PRESSURE SYSTEM WHICH TRIGGERED SEVERE WEATHER ACROSS THE REGION LAST EVENING...IS LOCATED OVER CENTRAL WISCONSIN THIS MORNING. THIS LOW WILL MOVE INTO NORTHERN LAKE MICHIGAN TONIGHT. A TIGHT PRESSURE GRADIENT ASSOCIATED WITH THE LOW WILL CREATE VERY WINDY CONDITIONS ACROSS THE REGION TODAY. WINDS FOR MUCH OF THE DAY WILL BE SUSTAINED AT 25 TO 35 MPH FROM THE WEST...AND WILL GUST AT TIMES TO BETWEEN 40 AND 45 MPH. THEREFORE...A WIND ADVISORY HAS BEEN ISSUED FOR TODAY FOR ALL OF EASTERN IOWA... NORTHWEST AND WEST CENTRAL ILLINOIS AND EXTREME NORTHEAST MISSOURI. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. A DISTURBANCE WILL BRING THE THREAT FOR RAIN AND POSSIBLY A FEW THUNDERSTORMS LATE TUESDAY INTO THURSDAY. HOWEVER...IT APPEARS AS THOUGH THE ATMOSPHERE WILL NOT BE CONDUCIVE FOR THE DEVELOPMENT OF SEVERE THUNDERSTORMS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT. && MORE INFORMATION MAY BE OBTAINED AT THE FOLLOWING URL: http://www.crh.noaa.gov/dvn 05
The national radar mosaic for the moment the first event began.
1 high wind. Local standard time, as filed.
KCWI AWOS
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, May 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: 5359311.