Hail, Grundy
- When
- July 22, 12:35 PM CST to 12:40 PM CST
- Where
- Grundy County, 4 mi W of Morris
- Measured
- 0.75 in hail
- Reported by
- TRAINED SPOTTER
- Coordinates
- 41.367, -88.500
On the morning of July 22, a cold front extended from central Great Lakes region, southwestward through southern Wisconsin and into central Iowa. Ahead of the frontal boundary, Northern Illinois and Indiana were very moist, humid and unstable.
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 LOT wrote it up.
On the morning of July 22, a cold front extended from central Great Lakes region, southwestward through southern Wisconsin and into central Iowa. Ahead of the frontal boundary, Northern Illinois and Indiana were very moist, humid and unstable. In the late morning hours, a line of thunderstorms crossed the Mississippi River into western Illinois. This line continued to develop eastward and by around 1:00PM began to enter Grundy and Will Counties. The storms had continued to intensify with their eastward progression and produced up to penny sized hail and wind gusts up to 55 kts. The line of storms then continued into northwestern Indiana and over southern Lake Michigan. Isolated incidents of significant tree and power line damage were also reported in the storm's path.
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 Chicago, IL wrote its last area forecast discussion before the first event at Jul 22, 11:45 AM CST, 50 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO IL 1245 PM CDT THU JUL 22 2004 .DISCUSSION... THE MAIN ISSUE THIS PACKAGE WILL HOVER AROUND THIS AFTERNOON AND EVENING DEALING WITH TSRA AND COLD FROPA. UNLIKE YESTERDAY WHEN THE CWA DELT WITH WARM SECTOR DEVELOPMENT AS FUNCTION OF MID-LVL S/WV TROUGH PASSAGE AND ITS ATTENDANT SFC TROUGH, TODAYS ACTIVITY APPEARS AS IF IT WILL BE A FUNCTION OF COLD FROPA GIVEN THE FRONT WILL SERVE AS THE FOCI. THE QUESTION THEN BECOMES TIMING BETWEEN FRONTAL PLACEMENT RELATIVE TO AN APPROACHING, YET TEMPERED, MID-LVL S/WV TROUGH. THE COLD FRONT SHOULD BE ADVANCING SOUTHWARD TODAY AND INTO THE NORTHERN PORTION IL THIS AFTERNOON. SHORT-RANGE NWP DEPICTS HIT- OR-MISS TS DEVELOPMENT ACROSS THE NRN AND CNTRL PORTION OF THE CWA BY 21Z THEN THE STORMS MOVE SOUTH SOUTHEAST WITH THE FRONT... CLEARING THE SOUTHEASTERN TIER OF THE CWA BY 9 UTC. THIS SOLUTION APPEARS REASONABLE GIVEN THE CURRENT PLACEMENT AND PROGRESSION OF THE FRONT AND THE SLOWLY AMPLIFYING S/WV TROUGH. HAVE TIMED THE ZONES ACCORDING ENDING PRECIP FROM NORTH TO SOUTH. BEHIND TONIGHTS FROPA THE CWA WILL SEE A DRY AND RELATIVELY COOL WEEKEND WITH A SLOW TEMPERATURE MODIFICATION INTO THE MIDDLE OF NEXT WEEK. LEFT THE FAR EXTENDED PERIODS ALONE AS THERE IS MUCH UNCERTAINTY WITH THE GFS AND ECWMF TOWARD THE EVOLUTION OF A CLOSED LOW AND ITS SUBSEQUENT KICKER ACROSS THE NORTH CNTRL CONUS. && .AVIATION DISCUSSION REGARDING 18Z TAFS... MAIN QUESTION WITH AFTN TAFS CONCERNS TSTM POTL OVR TERMINAL AREA. 1730 SATLT IMAGERY SHOWS TSTM CLUSTER CONTG TO PROPAGATE EWD ACRS NRN AND CNTRL IL. MOST RAPID CONVECTION DVLPG S OF I-80 FROM VYS...SWD INTO SPI VCTY. THIS COMPLEX WILL LIKELY PROPAGATE SEWD TO S OF TERMINALS...BUT MAY HAVE SOME SHWRS/TSTMS IN SRN PORTION OF CHI AREA AND NWRN IN AS MORE STRATIFIED ANVIL PORTION OF CLUSTER PASSES THROUGH ERLY-MID AFTN. CIGS AND VIS MAY TEMPORARILY DROP INTO MVFR RANGE...MNLY FROM ARR-MDW SWD. AREA SHOULD GO VFR WITH JUST HI LVL OVC BY LATER THIS AFTN. OTHER FACTOR IS WIND DIRECTION. DFUS COLD FRONT NOW IN THE PROCESS OF SAGGING SEWD THRU NRN IL. THIS FRONT WILL BCM MORE WELL DEFINED THRU AFTN AND EVENING SO VRBL WINDS UNDER 10 KTS TO BCM NLY-NELY BY 21-23Z...AND INCRS TO 10-15 KTS FROM NNE BY 03Z. MERZLOCK && .LOT...WATCHES/WARNINGS/ADVISORIES... .IL...NONE. .IN...NONE. .LK MI...NONE.
HAZARDOUS WEATHER OUTLOOK...UPDATED NATIONAL WEATHER SERVICE CHICAGO IL 1250 PM CDT THU JUL 22 2004 ILZ003>006-008-010>014-019>022-023-032-033-039-INZ001-002-010-011-019 -231100- WINNEBAGO-BOONE-MCHENRY-LAKE IL-OGLE-LEE-DE KALB-KANE-DU PAGE-COOK- LA SALLE-KENDALL-GRUNDY-WILL-KANKAKEE-LIVINGSTON-IROQUOIS-FORD- LAKE IN-PORTER-NEWTON-JASPER-BENTON- 1250 PM CDT THU JUL 22 2004 THIS PORTION OF THE HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL AND NORTHEAST ILLINOIS...AND NORTHWEST INDIANA. .DAY ONE... THIS AFTERNOON AND TONIGHT A SEVERE THUNDERSTORM WATCH IS IN EFFECT UNTIL 6 PM CDT...FOR MOST OF NORTHERN ILLINOIS...SOUTH OF A LINE FROM FORRESTON TO GENOA TO EVANSTON AND IS ALSO IN EFFECT FOR NORTHWEST INDIANA. THE MAIN SEVERE WEATHER THREATS ARE DAMAGING WINDS AND HEAVY RAIN. THE THREAT OF SEVERE WEATHER WILL DIMINISH AFTER 6 PM CDT THIS EVENING... HOWEVER A FEW THUNDERSTORMS WILL STILL BE POSSIBLE OVERNIGHT. .DAYS TWO THROUGH SEVEN... FRIDAY THROUGH WEDNESDAY THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... SPOTTERS WILL BE NEEDED THIS AFTERNOON AND THIS EVENING. && COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO WEBPAGE: WWW.CRH.NOAA.GOV/LOT (LOWER CASE) LMZ740>746-766-231100- WINTHROP HARBOR IL TO NEW BUFFALO MI- LAKE MICHIGAN- 1250 PM CDT THU JUL 22 2004 THIS PORTION OF THE HAZARDOUS WEATHER OUTLOOK IS FOR THE ILLINOIS AND INDIANA WATERS OF LAKE MICHIGAN. .DAY ONE... THIS AFTERNOON AND TONIGHT A SEVERE THUNDERSTORM WATCH IS IN EFFECT UNTIL 6 PM CDT FOR SOUTHERN LAKE MICHIGAN. THE MAIN SEVERE WEATHER THREATS ARE DAMAGING WINDS AND HEAVY RAIN. THE THREAT OF SEVERE WEATHER WILL DIMINISH AFTER 6 PM CDT. .DAYS TWO THROUGH SEVEN... FRIDAY THROUGH WEDNESDAY THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. && COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO WEBPAGE: WWW.CRH.NOAA.GOV/LOT (LOWER CASE)
PRELIMINARY LOCAL STORM REPORT ... CORRECTION
NATIONAL WEATHER SERVICE CHICAGO IL
955 AM CDT THU JUL 22 2004
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION...ST.. ...SOURCE....
..REMARKS..
0950 AM TSTM WND DMG 9 NW ROCHELLE 42.01N 89.19W
07/21/2004 OGLE IL PUBLIC
TREES DOWN IN CHANA
1000 AM TSTM WND DMG ROCHELLE 41.92N 89.06W
07/21/2004 OGLE IL LAW ENFORCEMENT
TREE LIMBS DOWN.
1000 AM TSTM WND DMG 6 NNW ROCHELLE 42.00N 89.11W
07/21/2004 OGLE IL PUBLIC
LARGE LIMBS DOWN IN KINGS.
0400 PM HAIL MONTGOMERY 41.73N 88.34W
07/21/2004 0.88 INCH KANE IL EMERGENCY MNGR
REPORTED AT ROUTE 30 AND ROUTE 31.
0415 PM TSTM WND DMG 2 W BOLINGBROOK 41.70N 88.12W
07/21/2004 WILL IL TRAINED SPOTTER
TREE LIMBS DOWN AT BOUGHTON AND WEBER ROAD.
0415 PM TSTM WND DMG BOLINGBROOK 41.70N 88.08W
07/21/2004 WILL IL AMATEUR RADIO
TREES DOWN. ONE ON ROAD AT ROYCE AND CONCORD.
0418 PM TSTM WND DMG PLAINFIELD 41.62N 88.20W
07/21/2004 WILL IL EMERGENCY MNGR
TREE FELL ONTO A POWER LINE.
0420 PM TSTM WND DMG NAPERVILLE 41.76N 88.15W
07/21/2004 DUPAGE IL AMATEUR RADIO
24 INCH DIAMETER TREE DOWN.
0425 PM FLOOD AURORA 41.77N 88.29W
07/21/2004 KANE IL TRAINED SPOTTER
MINOR STREET FLOODING.
0425 PM HAIL 5 S AURORA 41.70N 88.29W
07/21/2004 0.75 INCH KENDALL IL TRAINED SPOTTER
0426 PM HAIL ROMEOVILLE 41.65N 88.09W
07/21/2004 0.88 INCH WILL IL EMERGENCY MNGR
REPORTED AT INTERSTATE 55 AND BUDLER ROADS
0427 PM HAIL ROMEOVILLE 41.65N 88.09W
07/21/2004 0.75 INCH WILL IL EMERGENCY MNGR
0428 PM TSTM WND DMG BOLINGBROOK 41.70N 88.08W
07/21/2004 WILL IL EMERGENCY MNGR
TREE LIMBS DOWN NEAR BOUGHTON AND WEBER.
0430 PM TSTM WND DMG NAPERVILLE 41.76N 88.15W
07/21/2004 DUPAGE IL TRAINED SPOTTER
12 INCH DIAMETER TREE BRANCHES DOWN.
0433 PM TSTM WND DMG WOODRIDGE 41.74N 88.04W
07/21/2004 DUPAGE IL EMERGENCY MNGR
TREE LIMBS DOWN NEAR ROUTE 53 AND 75TH STREET.
0435 PM TSTM WND DMG LEMONT 41.67N 87.99W
07/21/2004 COOK IL AMATEUR RADIO
TREES DOWN AT MAIN AND COTLAND...MAIN AND 83.
0442 PM TSTM WND DMG WILLOWBROOK 41.76N 87.95W
07/21/2004 DUPAGE IL AMATEUR RADIO
ESTIMATED WIND GUSTS TO 65-70 MPH. LARGE TREE LIMBS DOWN.
REPORTED NEAR INTERSTATE 55 AND ROUTE 83.
0455 PM HAIL CHICAGO 41.88N 87.63W
07/21/2004 0.75 INCH COOK IL TRAINED SPOTTER
64TH AND MAPLE IN CHICAGO LAWN.
0458 PM TSTM WND DMG CHICAGO RIDGE 41.70N 87.78W
07/21/2004 COOK IL EMERGENCY MNGR
TREE LIMBS DOWN.
0500 PM TSTM WND DMG BURBANK 41.74N 87.77W
07/21/2004 COOK IL TRAINED SPOTTER
LARGE TREE LIMBS...TREES...POWER LINES...AND POWER POLES
DOWN.
0500 PM TSTM WND GST CHICAGO 41.88N 87.63W
07/21/2004 77 MPH COOK IL TRAINED SPOTTER
MEASURED AT 64TH AND MAPLE IN CHICAGO LAWN. LARGE TREE
BRANCHES DOWN.
0500 PM TSTM WND DMG ALSIP 41.67N 87.74W
07/21/2004 COOK IL LAW ENFORCEMENT
LARGE LIMBS AND SEVERAL TREES AND FLAGPOLES DOWN. WINDS
ESTIMATED TO BE 70 MPH.
0501 PM TSTM WND DMG BRIDGEVIEW 41.74N 87.81W
07/21/2004 COOK IL AMATEUR RADIO
SEVEN INCH DIAMETER TREE SNAPPED IN HALF AT 87TH AND
ROBERTS.
0514 PM TSTM WND GST GARY 41.60N 87.34W
07/21/2004 60 MPH LAKE IN SHIP
PEAK WIND OF 52 KNOTS MEASURED AT TRUMP CASINO IN
BUFFINGTON HARBOR.
0525 PM FLOOD HIGHLAND 41.55N 87.46W
07/21/2004 LAKE IN EMERGENCY MNGR
STREET FLOODING UP TO THE CURBS. SECTIONS OF 45TH STREET
IMPASSIBLE.
0527 PM TSTM WND DMG 1 E GARY 41.60N 87.32W
07/21/2004 LAKE IN PUBLIC
75 MPH WIND MEASURED ON HOME WIND GAGE. TREES...LIMBS AND
POWER LINES DOWN.
0535 PM TSTM WND DMG PORTAGE 41.59N 87.18W
07/21/2004 PORTER IN LAW ENFORCEMENT
TREE LIMBS AND POWER LINES DOWN.
0535 PM TSTM WND DMG BEVERLY SHORES 41.69N 86.98W
07/21/2004 PORTER IN PARK/FOREST SRVC
20 FOOT TREE DONW ON THE ROAD AND LIMBS DOWN. REPORT FROM
INDIANA DUNES NATIONAL LAKESHORE.
0535 PM MARINE TSTM WIND BEVERLY SHORES 41.69N 86.98W
07/21/2004 0 MPH PORTER IN PARK/FOREST SRVC
BOAT CAPSIZED 100 YARDS OFF BEVERLY SHORES BEACH. NO
INJURIES.
0550 PM MARINE TSTM WIND 4 ENE BEVERLY SHORES 41.71N 86.91W
07/21/2004 75 MPH LA PORTE IN C-MAN STATION
MICHIGAN CITY GLERL OBSERVATION.
0553 PM TSTM WND DMG HOBART 41.53N 87.27W
07/21/2004 LAKE IN LAW ENFORCEMENT
60 MPH WINDS ESTIMATED.
0615 PM TSTM WND DMG 4 S SCHNEIDER 41.13N 87.45W
07/21/2004 NEWTON IN LAW ENFORCEMENT
TREES DOWN ON STATE ROAD 10.
0620 PM HAIL RENSSELAER 40.94N 87.15W
07/21/2004 1.00 INCH JASPER IN EMERGENCY MNGR
0625 PM TSTM WND DMG MERRILLVILLE 41.47N 87.33W
07/21/2004 LAKE IN TRAINED SPOTTER
TREE DAMAGE AND STOP LIGHT FIXTURE DAMAGE ON ROUTE 30.
0625 PM TSTM WND DMG MOROCCO 40.95N 87.45W
07/21/2004 NEWTON IN LAW ENFORCEMENT
TREES DOWN ON 114.
0642 PM HAIL 2 NW REMINGTON 40.78N 87.18W
07/21/2004 0.75 INCH JASPER IN CO-OP OBSERVER
0650 PM TSTM WND DMG WHEATFIELD 41.19N 87.05W
07/21/2004 JASPER IN LAW ENFORCEMENT
NUMEROUS TREES DOWN IN WHEATFIELD.
&&The Chicago radar (KLOT), 44 km away, was scanning. The volume nearest the first event began at 18:35 UTC.
4 thunderstorm wind, 1 hail. Local standard time, as filed.
Large tree limbs knocked down near Bronk Rd. and Caton Farm Rd.
8 inch diameter tree limbs torn down at the intersection of Ridge Rd. and Manhattan Rd., west of Rt. 52.
Large tree limbs down on Gaylord St., south of Division St.
Power lines knocked down on Winding Creek and Oak Creek Rds, near Rt. 71 between Yorkville and Oswego.
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, 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: 5414286, 5414287, 5414356, 5414357, 5414358.