Strong to severe thunderstorms developed over parts of northern Illinois during the early morning hours of July 23rd producing torrential rainfall and flash flooding in some areas, including parts of Chicago.
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.
Strong to severe thunderstorms developed over parts of northern Illinois during the early morning hours of July 23rd producing torrential rainfall and flash flooding in some areas, including parts of Chicago.
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, 8:59 PM CST, 2 hours 56 minutes earlier.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
959 PM CDT FRI JUL 22 2011
.DISCUSSION...
354 PM CDT
HEAT AND THE PROSPECTS OF MORE HEAVY RAINFALL ARE THE MAIN FORECAST
CONCERNS OVER THE NEXT FEW DAYS.
AS FOR THE HEAT HEADLINES...I DECIDED TO CANCEL THE HEAT WATCH FOR
THE NORTHERN SECTIONS OF THE AREA...GENERALLY ALONG AND NORTH OF I-88
AS IT APPEARS UNLIKELY FOR THESE AREAS TO REACH THE DANGEROUS
CRITERIA. IN SPITE OF THIS...THINGS SHOULD BEGIN WARMING BACK TO
NEAR 90 IN THESE AREAS...ESPECIALLY BY SUNDAY. FARTHER
SOUTH...GENERALLY SOUTH OF I-80 I EXTENDED THE WARNING THROUGH 02
UTC ON MONDAY. IN THE MIDDLE I LEFT THE WATCH FROM 12 UTC SUNDAY TO
02 MONDAY. THIS IS FOR AREAS ALONG THE I-80 CORRIDOR.
A POTENT MID LEVEL SHORT WAVE WILL SHIFT EASTWARD ACROSS NORTH
DAKOTA TONIGHT INTO SATURDAY. IN RESPONSE TO THIS...A SURFACE LOW IS
EXPECTED SHIFT EASTWARD FROM THE NORTHERN HIGH PLAINS TO SOUTHERN MN
BY SATURDAY EVENING. THIS WILL CAUSE THE WARM FRONT...CURRENTLY
ACROSS THE AREA...TO MOVE NORTHWARD TO SOUTHERN WI TONIGHT. SEVERAL
MID LEVEL DISTURBANCES EJECTING OUT ACROSS CENTRAL PLAINS...WILL
CONTINUE TO DEVELOP CONVECTION ACROSS IOWA THIS EVENING. WITH TIME
TONIGHT GOOD MOIST ADVECTION WITHIN A WARM AIR ADVECTION REGIME
SHOULD ALLOW THIS ACTIVITY TO CONGEAL INTO ANOTHER MCS. IT APPEARS
THAT THIS MCS COULD HIT THE SAME AREAS AS THIS MORNINGS MCS.
ADDITIONALLY...GIVEN THAT THE ATMOSPHERIC PROFILE HAS CHANGED
LITTLE...IT CAN BE EXPECTED THAT THESE STORMS WILL ALSO BE EFFICIENT
RAINMAKERS. THIS ACTIVITY SHOULD CONTINUE ON SATURDAY MORNING ACROSS
THE AREA. IN ADDITION TO THE HEAVY RAIN...STRONG WINDS ARE AGAIN POSSIBLE
WITH THESE STORMS.
SIMILAR TO TODAY...IT APPEARS THERE WILL BE SOME DRY TIME IN THE
AFTERNOON. HOWEVER...ADDITIONAL CONVECTIVE DEVELOPMENT COULD OCCUR
AGAIN BY LATE AFTERNOON. HOWEVER...IF THE LOW LEVEL WIND FIELD IS
SIGNIFICANTLY DISRUPTED...AS IT WAS TODAY...IT MAY LIMIT THE
OVERALL THREAT ACROSS THE AREA...EXCEPT NEAR ANY BOUNDARIES THAT
BECOME ESTABLISHED.
A FINAL ROUND OF THUNDERSTORMS LOOKS TO BE IN THE WORKS BY SUNDAY
AFTERNOON AS THE COLD FRONT FINALLY PUSHES ACROSS THE AREA. THERE
COULD BE A SOME STRONG TO SEVERE STORMS DURING THIS PERIOD.
HOWEVER...THE MAIN STORY WITH THIS FRONT WILL BE THE PLEASANT AIR
MASS IT USHERS IN ACROSS THE REGION. SURFACE HIGH PRESSURE WILL
BUILD IN ACROSS THE WESTERN GREAT LAKES IN THE WAKE OF THIS FRONT ON
MONDAY AND TUESDAY. THIS WILL PRODUCE COOL AND DRY CONDITIONS FOR
MONDAY AND TUESDAY. UNFORTUNATELY...THIS WILL BE RELATIVELY SHORT
LIVED AS THE THE HEAT MAKES A RETURN BY WEDNESDAY AND THURSDAY AS
THE UPPER RIDGE BUILDS NORTHWARD AGAIN. THIS COULD PUT TEMPERATURES
BACK INTO THE MID 90S AREA WIDE BY THURSDAY
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* THUNDERSTORM POTENTIAL OVERNIGHT/SATURDAY.
RATZER
//DISCUSSION...UPDATED 0130Z...
THUNDERSTORM COMPLEX OVER CENTRAL IOWA HAS BECOME MORE ORGANIZED
OVER THE PAST 1-2 HOURS...WITH RADAR INDICATIONS OF REAR INFLOW
JET DEVELOPMENT AND SOME INCREASE IN FORWARD SPEED. COMPLEX IS
EXPECTED TO CONTINUE TO TRACK EAST-SOUTHEAST ALONG INSTABILITY
GRADIENT NORTH OF SURFACE FRONTAL BOUNDARY WHICH LIES OFF TO THE
SOUTH OF THE TERMINALS. HAVE SPED UP TIMING FROM 00Z ISSUANCE TO
AROUND 05Z AT KRFD...AND UPGRADED TO TEMPO TSRA THERE...AND MOVED
UP THE CHICAGO TERMINAL TIMING FOR VCTS TO 0630-0700Z. BULK OF
STRONGER TS MAY MOVE JUST SOUTH OF TERMINALS...BUT WILL MONITOR
NEXT 1-2 HOURS FOR POSSIBLE TEMPO TSRA FOR CHICAGO TERMINALS. IN
ADDITION...THUNDERSTORMS HAVE FORMED AS PREVIOUSLY DISCUSSED TO
THE EAST OF IKK...ABOUT 20 NM SOUTH OF KGYY TO NEAR KVPZ. THESE
SHOULD CONTINUE TO MOVE EAST AND NOT DIRECTLY AFFECT GYY OR OTHER
TERMINALS OTHER THAN ARRIVAL/DEPARTURE ROUTES INTO CHI. WOULD
EXPECT WEAKENING/DISSIPATION TREND OF THESE CELLS NEXT FEW HOURS.
RATZER
PREVIOUS DISCUSSION FROM 00Z...
ORD/MDW TDWRS DEPICTING WEAK LAKE BREEZE BOUNDARY HAS BEEN MAKING
SOME PROGRESS WESTWARD ACROSS COOK COUNTY EARLY THIS EVENING...AND
WAS ROUGHLY ALONG A PWK-NILES-BRIDGEPORT LINE AT 2330Z.
EXTRAPOLATION OF THIS FEATURE SUGGESTS IT HAS SLOWED JUST A BIT IN
THE LAST HOUR...THOUGH IT MAY IMPINGE UPON BOTH ORD AND MDW
IN THE 010-0130Z TIME FRAME. MESONET WINDS BEHIND SHOW LIGHT EAST
WIND QUICKLY BECOMING VARIABLE...SO SUSPECT IT WONT HAVE A VERY
PRONOUNCED AFFECT THOUGH EXPECT IT WILL INDUCE MORE OF A LIGHT
VARIABLE WIND FIELD RATHER THAN CURRENT LIGHT SOUTHWEST WINDS.
OTHERWISE...THUNDERSTORM TRENDS ARE THE MAIN CONCERN OVER THE NEXT
12-24 HOURS. VISIBLE SATELLITE SHOWS MOST OF FORECAST AREA
RELATIVELY CUMULUS FREE AT THIS HOUR...SAVE FOR A LITTLE CONGESTUS
ALONG OLD OUTFLOW BOUNDARY IN THE VICINITY OF KANKAKEE. WEAK
RETURN NOTED ON KLOT 88D IN THIS VICINITY SUPPORTS RECENT HRRR
FORECASTS OF SOME CONVECTIVE DEVELOPMENT THERE...THOUGH THESE
SHOULD NOT HAVE A DIRECT EFFECT ON IMMEDIATE TERMINAL AIRSPACE.
LARGER CONCERN OVER CONVECTION BACK ACROSS IOWA EARLY THIS EVENING
WHICH IS TIED TO MID LEVEL FEATURE WHICH IS PROGGED TO MOVE EAST
ALONG THE IA/MN BORDER TONIGHT AND ACROSS SOUTHERN WI SATURDAY
MORNING. GUIDANCE IN GENERAL AGREEMENT THAT THIS IS THE AREA TO
WATCH FOR CONTINUED CONVECTIVE DEVELOPMENT...WITH MID LEVEL
SUPPORT AND IN REGION OF BETTER LOW LEVEL JET FORCING OVERNIGHT
AND EARLY SATURDAY. MODEL FORECAST SUPPORT DEVELOPMENT OF COMPLEX
ACROSS NORTHERN IA/FAR SOUTHEAST MN/SOUTHWEST WI WHICH WOULD THEN
SPREAD SOUTHEAST INTO NORTHERN IL TOWARD MORNING. THUS VICINITY
THUNDER MENTION BEYOND 07-08Z AND LINGERING INTO SATURDAY MORNING
SEEMS PRUDENT. MAY UPGRADE TO A TEMPO IF COMPLEX CONTINUES TO
EXHIBIT INCREASING ORGANIZATION THIS EVENING.
TRENDS FOR SATURDAY WILL DEPEND HIGHLY ON DETAILS OF CONVECTION
THROUGH 15Z. WOULD EXPECT SOME DECREASE IN CONVECTIVE POTENTIAL
AFTER ANY MORNING COMPLEX...THEN A DIURNAL INCREASE IN POTENTIAL
DURING THE AFTERNOON. CONFIDENCE REALLY TOO LOW ON DETAILS BEYOND
15Z AT THIS TIME TO CHANGE CB CLOUD GROUP FOR THE LATER AFTERNOON
HOURS. SOUTH WINDS EXPECTED TO SHIFT JUST A BIT SOUTH-SOUTHEAST
LATER IN THE DAY AS LOW PRESSURE MOVES INTO MINNESOTA AND BACKS
LARGE SCALE LOW LEVEL FLOW OVER THE MIDWEST.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* HIGH CONFIDENCE OF NO CONVECTION IN IMMEDIATE ORD/MDW VICINITY
THROUGH MIDNIGHT...THEN INCREASING POTENTIAL BEYOND 06Z.
* MEDIUM-LOW CONFIDENCE IN CONVECTION FORECAST BEYOND 06Z.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...CHC TSRA.
MONDAY...VFR.
TUESDAY...VFR.
WEDNESDAY...VFR.
THURSDAY...VFR. SLGT CHC TSRA.
RATZER
&&
.MARINE...
414 PM CDT
GENERALLY SOUTHERLY FLOW IN PLACE ACROSS THE LAKE LATE THIS
AFTERNOON...WITH RATHER LIGHT WINDS ALSO IN PLACE AS PRESSURE
GRADIENT REMAINS BAGGY. TROUGH OF LOW PRESSURE TO THE NORTH WILL
CONTINUE TO SHIFT EAST WITH TIME TONIGHT...WITH A RIDGE OF HIGH
PRESSURE BUILDING IN OVER THE LAKE FROM THE NORTH. WINDS WILL
CONTINUE TO REMAIN LIGHT WITH THE EXCEPTION FOR AREAS ACROSS THE
NORTHERN HALF WHERE THIS BUILDING HIGH PRESSURE WILL HELP TO
TIGHTEN THE PRESSURE GRADIENT AS WELL AS INCREASE THE WINDS. THEN
AS A TROUGH OF LOW PRESSURE WORKS ITS WAY NORTHEAST THROUGH THE
PLAINS AND UPPER MIDWEST INTO THE CENTRAL GREAT LAKES REGION
SATURDAY NIGHT INTO SUNDAY...WINDS WILL TURN TO THE SOUTH.
ALTHOUGH A RIDGE OF HIGH PRESSURE BUILDING IN FROM THE WEST WILL
HELP THE WINDS TURN MORE NORTHERLY WITH WINDS PICKING UP ONCE
AGAIN BEFORE THE RIDGE AXIS SHIFTS OVERHEAD.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...EXCESSIVE HEAT WARNING...ILZ023-ILZ032-ILZ033-ILZ039 UNTIL 9 PM
SUNDAY.
EXCESSIVE HEAT WATCH...ILZ019-ILZ020-ILZ021-ILZ022...7 AM
SATURDAY TO 9 PM SUNDAY.
IN...EXCESSIVE HEAT WATCH...INZ001-INZ002...7 AM SATURDAY TO 9 PM
SUNDAY.
EXCESSIVE HEAT WARNING...INZ010-INZ011-INZ019 UNTIL 9 PM SUNDAY.
LM...NONE.
&&HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
427 PM CDT FRI JUL 22 2011
ILZ003>006-008-010>014-019>023-032-033-039-INZ001-002-010-011-019-
232130-
WINNEBAGO-BOONE-MCHENRY-LAKE ILLINOIS-OGLE-LEE-DE KALB-KANE-
DUPAGE-COOK-LA SALLE-KENDALL-GRUNDY-WILL-KANKAKEE-LIVINGSTON-
IROQUOIS-FORD-LAKE INDIANA-PORTER-NEWTON-JASPER-BENTON-
427 PM CDT FRI JUL 22 2011 /527 PM EDT FRI JUL 22 2011/
THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL ILLINOIS...
NORTHEAST ILLINOIS AND NORTHWEST INDIANA.
.DAY ONE...TONIGHT.
WEATHER HAZARDS EXPECTED:
OPPRESSIVE HEAT AND HUMIDITY.
THUNDERSTORMS...SOME MAY PRODUCE:
HEAVY RAINFALL WITH FLASH FLOODING.
WINDS OVER 60 MPH.
FREQUENT LIGHTNING.
AREAS AFFECTED AND TIMING:
THE DANGEROUS HEAT AND HUMIDITY WILL CONTINUE...ESPECIALLY
SOUTH OF INTERSTATE 80.
THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS IOWA THIS
EVENING...BEFORE THEY TRACK EASTWARD ACROSS SOUTHERN WISCONSIN
AND FAR NORTHERN ILLINOIS LATE TONIGHT INTO SATURDAY MORNING.
AREAS NORTH OF INTERSTATE 80 WILL HAVE THE BEST CHANCE OF
THUNDERSTORMS.
DISCUSSION:
HEAT INDEX VALUES WILL LIKELY ONLY DROP TO THE LOW 90S BY
MIDNIGHT TONIGHT FOR AREAS SOUTH OF I-80. THIS WILL CONTINUE TO
LEAD TO DANGEROUS HEAT CONDITIONS.
VERY HEAVY RAINFALL MAY AGAIN ACCOMPANY THE THUNDERSTORMS LATE
TONIGHT INTO SATURDAY MORNING. THIS RAIN COULD FALL ON THE SAME
AREAS THAT EXPERIENCED HEAVY RAIN THIS MORNING. RUNOFF FROM
THIS RAIN COULD CAUSE ADDITIONAL FLASH FLOODING IN SOME AREAS.
.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.
HEAT INDEX VALUES AROUND 100 DEGREES ARE EXPECTED ACROSS MUCH OF
NORTHERN ILLINOIS AND NORTHWEST INDIANA FOR THE WEEKEND. SOUTH OF
I-80 THE HEAT WILL BE MORE EXTREME...HEAT INDEX VALUES AROUND 110
DEGREES ARE EXPECTED.
THERE WILL BE PERIODIC CHANCES FOR THUNDERSTORMS THROUGH SUNDAY
AND AGAIN BY THE MIDDLE OF NEXT WEEK.
.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION MAY BE NEEDED LATE TONIGHT INTO SATURDAY
MORNING.
&&
COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO
WEBPAGE: WEATHER.GOV/CHICAGO
LMZ740>745-232130-
WINTHROP HARBOR TO WILMETTE HARBOR-
WILMETTE HARBOR TO NORTHERLY ISLAND-
NORTHERLY ISLAND TO CALUMET HARBOR-CALUMET HARBOR TO GARY-
GARY TO BURNS HARBOR-BURNS HARBOR TO MICHIGAN CITY-
427 PM CDT FRI JUL 22 2011
THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE ILLINOIS NEARSHORE
WATERS OF LAKE MICHIGAN AND THE INDIANA NEARSHORE WATERS OF LAKE
MICHIGAN.
.DAY ONE...TONIGHT.
THERE IS A CHANCE OF STORMS LATE TONIGHT CAUSING WIND GUSTS IN
EXCESS OF 35 KNOTS AND FREQUENT LIGHTNING.
.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.
THERE WILL BE PERIODIC CHANCES FOR THUNDERSTORMS THROUGH SUNDAY
AND AGAIN BY THE MIDDLE OF NEXT WEEK.
&&
COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO
WEBPAGE: WEATHER.GOV/CHICAGO
LMZ080-261-362-364-366-563-565-567-669-671-673-675-777-779-868-
870-872-874-876-878-232130-
LAKE MICHIGAN FROM MICHIGAN CITY IN TO ST. JOSEPH MI 5 NM
OFFSHORE TO MID LAKE-
LAKE MICHIGAN FROM SEUL CHOIX POINT TO ROCK ISLAND PASSAGE 5 NM
OFFSHORE TO MID LAKE-
LAKE MICHIGAN SOUTH OF A LINE FROM SEUL CHOIX POINT TO THE
MACKINAC BRIDGE AND NORTH OF A LINE FROM CHARLEVOIX MI TO SOUTH
FOX ISLAND 5 NM OFFSHORE-
LAKE MICHIGAN FROM CHARLEVOIX TO POINT BETSIE MI 5 NM OFFSHORE TO
MID LAKE-
LAKE MICHIGAN FROM POINT BETSIE TO MANISTEE MI 5 NM OFFSHORE TO
MID LAKE-
LAKE MICHIGAN FROM ROCK ISLAND PASSAGE TO STURGEON BAY WI-
LAKE MICHIGAN FROM STURGEON BAY TO TWO RIVERS WI 5 NM OFFSHORE TO
MID LAKE-
LAKE MICHIGAN FROM TWO RIVERS TO SHEBOYGAN WI 5 NM OFFSHORE TO
MID LAKE-
LAKE MICHIGAN FROM SHEBOYGAN TO PORT WASHINGTON WI 5 NM OFFSHORE
TO MID LAKE-
LAKE MICHIGAN FROM PORT WASHINGTON TO NORTH POINT LIGHT WI 5 NM
OFFSHORE TO MID LAKE-
LAKE MICHIGAN FROM NORTH POINT LIGHT TO WIND POINT WI 5 NM
OFFSHORE TO MID LAKE-
LAKE MICHIGAN FROM WIND POINT WI TO WINTHROP HARBOR IL 5 NM
OFFSHORE TO MID LAKE-
LAKE MICHIGAN FROM WINTHROP HARBOR TO WILMETTE HARBOR IL 5 NM
OFFSHORE TO MID LAKE-
LAKE MICHIGAN FROM WILMETTE HARBOR IL TO MICHIGAN CITY IN 5 NM
OFFSHORE TO MID LAKE-
LAKE MICHIGAN FROM PENTWATER TO MANISTEE MI 5 NM OFFSHORE TO MID
LAKE-
LAKE MICHIGAN FROM WHITEHALL TO PENTWATER MI 5 NM OFFSHORE TO MID
LAKE-
LAKE MICHIGAN FROM GRAND HAVEN TO WHITEHALL MI 5 NM OFFSHORE TO
MID LAKE-
LAKE MICHIGAN FROM HOLLAND TO GRAND HAVEN MI 5 NM OFFSHORE TO MID
LAKE-
LAKE MICHIGAN FROM SOUTH HAVEN TO HOLLAND MI 5 NM OFFSHORE TO MID
LAKE-
LAKE MICHIGAN FROM ST. JOSEPH TO SOUTH HAVEN MI 5 NM OFFSHORE TO
MID LAKE-
427 PM CDT FRI JUL 22 2011
THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE OPEN WATERS OF LAKE
MICHIGAN.
.DAY ONE...TONIGHT.
THERE IS A CHANCE OF STORMS LATE TONIGHT CAUSING WIND GUSTS
IN EXCESS OF 35 KNOTS AND FREQUENT LIGHTNING.
.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.
THERE WILL BE PERIODIC CHANCES FOR THUNDERSTORMS ACROSS THE LAKE
THROUGH SUNDAY.
THERE ARE ADDITIONAL CHANCES FOR THUNDERSTORMS TUESDAY NIGHT
THROUGH THURSDAY...MAINLY FOR THE NORTHERN HALF OF THE LAKE.
&&
COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO
WEBPAGE: WEATHER.GOV/CHICAGO
KJBPRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
808 PM CDT FRI JUL 22 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0530 AM HEAVY RAIN 7 W ROCKTON 42.45N 89.21W
07/22/2011 M0.92 INCH WINNEBAGO IL CO-OP OBSERVER
MEASURED BY SHIRLAND CO-OP OBSERVER.
0630 AM HEAVY RAIN 1 W BEACH PARK 42.42N 87.88W
07/22/2011 M2.19 INCH LAKE IL COCORAHS
STORM TOTAL SO FAR. 0.70 INCHES MEASURED IN THE PAST 60
MINUTES. STANDING WATER AND DITCHES FILLING UP.
0700 AM HEAVY RAIN 2 W GURNEE 42.38N 87.98W
07/22/2011 M2.24 INCH LAKE IL COCORAHS
0700 AM HEAVY RAIN HARVARD 42.42N 88.62W
07/22/2011 M1.17 INCH MCHENRY IL CO-OP OBSERVER
0700 AM HEAVY RAIN 2 N SPRING GROVE 42.47N 88.24W
07/22/2011 M1.71 INCH MCHENRY IL CO-OP OBSERVER
0700 AM HEAVY RAIN 5 NW WOODSTOCK 42.36N 88.51W
07/22/2011 M1.48 INCH MCHENRY IL CO-OP OBSERVER
0700 AM HEAVY RAIN 2 N WAUKEGAN 42.40N 87.87W
07/22/2011 M2.10 INCH LAKE IL COCORAHS
0700 AM HEAVY RAIN 2 SE LAKEMOOR 42.32N 88.18W
07/22/2011 M1.69 INCH LAKE IL COCORAHS
0700 AM HEAVY RAIN 1 W BEACH PARK 42.42N 87.88W
07/22/2011 M1.49 INCH LAKE IL COCORAHS
0700 AM HEAVY RAIN BEACH PARK 42.42N 87.86W
07/22/2011 M2.06 INCH LAKE IL ASOS
SINCE 100 AM AT WAUKEGAN REGIONAL AIRPORT.
0700 AM HEAVY RAIN 2 NE GURNEE 42.40N 87.91W
07/22/2011 M2.38 INCH LAKE IL COCORAHS
0725 AM HEAVY RAIN WADSWORTH 42.44N 87.92W
07/22/2011 M2.80 INCH LAKE IL BROADCAST MEDIA
0.50 INCHES BETWEEN 655 AM AND 715 AM.
0745 AM FLOOD BEACH PARK 42.42N 87.86W
07/22/2011 LAKE IL EMERGENCY MNGR
NORTH SHERIDAN ROAD SOUTH OF WEST WADSWORTH ROAD CLOSED
FROM 745 AM TO 100 PM DUE TO 7-8 INCHES OF STANDING WATER
ON ROAD SURFACE.
0750 AM HEAVY RAIN 3 ENE MACHESNEY PARK 42.38N 88.98W
07/22/2011 M1.09 INCH WINNEBAGO IL COCORAHS
0755 AM HEAVY RAIN GURNEE 42.38N 87.94W
07/22/2011 M3.25 INCH LAKE IL PUBLIC
STORM TOTAL SO FAR.
0800 AM HEAVY RAIN WINTHROP HARBOR 42.48N 87.83W
07/22/2011 M1.28 INCH LAKE IL COCORAHS
0842 AM HEAVY RAIN 4 NW ROCKFORD 42.31N 89.12W
07/22/2011 M1.37 INCH WINNEBAGO IL CO-OP OBSERVER
STORM TOTAL SO FAR. 0.95 INCHES BETWEEN 715 AM AND TIME
OF REPORT.
0900 AM HEAVY RAIN ARLINGTON HEIGHTS 42.09N 87.98W
07/22/2011 E0.00 INCH COOK IL TRAINED SPOTTER
ESTIMATED 1 TO 2 INCHES.
0920 AM HEAVY RAIN 3 NNE ELBURN 41.93N 88.45W
07/22/2011 M0.63 INCH KANE IL COCORAHS
IN 15 MINUTES.
0933 AM TSTM WND GST DUPAGE AIRPORT 41.92N 88.25W
07/22/2011 M45.00 MPH DUPAGE IL ASOS
0945 AM TSTM WND GST ELMHURST 41.90N 87.94W
07/22/2011 M56.50 MPH DUPAGE IL TRAINED SPOTTER
MEASURED WITH A CAR ANEMOMETER. BRYAN MIDDLE SCHOOL AT
YORK ROAD.
0947 AM TSTM WND GST OHARE AIRPORT 41.98N 87.90W
07/22/2011 M43.00 MPH COOK IL ASOS
0953 AM HEAVY RAIN ARLINGTON HEIGHTS 42.09N 87.98W
07/22/2011 M1.00 INCH COOK IL TRAINED SPOTTER
IN 15 MINUTES UP TO TIME OF REPORT.
0955 AM HEAVY RAIN OHARE AIRPORT 41.98N 87.90W
07/22/2011 M0.75 INCH COOK IL ASOS
MEASURED IN 8 MINUTES BETWEEN 947AM AND 955 AM. 0.55
INCHES FELL BETWEEN 947 AM AND 951 AM.
0957 AM HEAVY RAIN 1 NNE BLOOMINGDALE 41.96N 88.08W
07/22/2011 M0.87 INCH DUPAGE IL COCORAHS
MEASURED IN 25 MINUTES UP TO TIME OF REPORT.
1000 AM HEAVY RAIN 3 ESE PLAINFIELD 41.60N 88.15W
07/22/2011 M0.76 INCH WILL IL COCORAHS
IN THE PAST 30 MINUTES.
1000 AM HEAVY RAIN GLEN ELLYN 41.87N 88.06W
07/22/2011 M1.16 INCH DUPAGE IL COCORAHS
RAINFALL IN ONE HOUR IN NORTH GLEN ELLYN.
1000 AM HEAVY RAIN 1 W ROSELLE 41.98N 88.10W
07/22/2011 M0.91 INCH DUPAGE IL COCORAHS
BETWEEN 940 AM AND 1000 AM.
1006 AM TSTM WND GST MIDWAY AIRPORT 41.78N 87.75W
07/22/2011 M54.00 MPH COOK IL ASOS
1013 AM HEAVY RAIN ARLINGTON HEIGHTS 42.09N 87.98W
07/22/2011 M0.85 INCH COOK IL TRAINED SPOTTER
IN 30 MINUTES UP TO TIME OF REPORT. INTERSECTION OF HINTZ
RD AND WINDSOR.
1015 AM MARINE TSTM WIND 4 NE CHICAGO 41.92N 87.57W
07/22/2011 M50.00 MPH LMZ741 IL C-MAN STATION
43 KNOT GUST MEASURED AT HARRISON-DEVER CRIB. 35
KNOT...OR 40 MPH...SUSTAINED WINDS. ANEMOMETER 85 FEET
ABOVE LAKE SURFACE.
1026 AM HEAVY RAIN MARENGO 42.25N 88.60W
07/22/2011 E1.80 INCH MCHENRY IL PUBLIC
MEASURED...BUT FIRST 10-15 MINUTES EXTREMELY HEAVY RAIN
WAS BLOWING SIDEWAYS...SO TOTAL MAY BE SLIGHTLY UNDER
WHAT ACTUALLY OCCURRED.
1030 AM HEAVY RAIN 2 WSW ELK GROVE VILLAGE 41.99N 88.03W
07/22/2011 M1.72 INCH DUPAGE IL COCORAHS
1.13 INCHES FROM 930 AM TO 1030 AM. 1.72 INCHES IN LAST
14 HOURS.
1030 AM HEAVY RAIN 1 W BEACH PARK 42.42N 87.88W
07/22/2011 M3.80 INCH LAKE IL COCORAHS
1053 AM TSTM WND GST GARY 41.60N 87.34W
07/22/2011 M54.00 MPH LAKE IN AWOS
MEASURED AT GARY AIRPORT.
1054 AM HEAVY RAIN PEOTONE 41.33N 87.80W
07/22/2011 M0.61 INCH WILL IL TRAINED SPOTTER
HEAVY RAIN FALL IN 16 MINUTES.
1058 AM HEAVY RAIN ENE COUNTRYSIDE 41.78N 87.88W
07/22/2011 M1.30 INCH COOK IL COCORAHS
IN THE PAST 60 MINUTES. AT 1030 AM AND 1035 AM RAIN RATE
WAS 5 INCHES PER HOUR.
1100 AM MARINE TSTM WIND 3 NNW BURNS HARBOR 41.65N 87.15W
07/22/2011 M44.00 MPH LMZ745 IN C-MAN STATION
38 KNOT GUST MEASURED AT BURNS HARBOR GLOS WEATHER
STATION. ANEMOMETER HEIGHT 33 FEET.
1100 AM HEAVY RAIN ELBURN 41.89N 88.47W
07/22/2011 M1.32 INCH KANE IL TRAINED SPOTTER
RAINFALL TOTAL 1.32 INCHES FROM 1 AM THROUGH 10 AM.
1140 AM HEAVY RAIN BERWYN 41.84N 87.79W
07/22/2011 M1.02 INCH COOK IL TRAINED SPOTTER
0100 PM HEAVY RAIN BEACH PARK 42.42N 87.86W
07/22/2011 M3.42 INCH LAKE IL ASOS
STORM TOTAL SINCE 100 AM AT WAUKEGAN REGIONAL AIRPORT.
1.36 INCHES BETWEEN 700 AM AND 100 PM.
0100 PM HEAVY RAIN OHARE AIRPORT 41.98N 87.90W
07/22/2011 M1.49 INCH COOK IL ASOS
STORM TOTAL SINCE 100 AM. 1.29 INCHES BETWEEN 700 AM AND
100 PM.
0102 PM HEAVY RAIN REMINGTON 40.76N 87.15W
07/22/2011 M0.63 INCH JASPER IN TRAINED SPOTTER
MEASURED IN 40 MINUTES.
&&
THIS REPORT MAY BE REVISED IF ANY FURTHER REPORTS ARE RECEIVED.
BNPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1155 PM CDT FRI JUL 22 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1145 PM HAIL 5 E LOWELL 41.29N 87.32W
07/22/2011 E0.25 INCH LAKE IN LAW ENFORCEMENT
INTERSECTION OF INTERSTATE 65 AND ROUTE 2. FROM INDIANA
STATE POLICE.
&&
RATZERSPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1211 AM CDT SAT JUL 23 2011
ILZ003-008-010-230615-
LEE IL-OGLE IL-WINNEBAGO IL-
1211 AM CDT SAT JUL 23 2011
...SPECIAL WEATHER STATEMENT...
AT 1207 AM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED STRONG
THUNDERSTORMS ALONG A LINE EXTENDING FROM 11 MILES WEST OF LAKE
SUMMERSET TO FORRESTON TO POLO...MOVING EAST AT 30 MPH.
WINDS UP TO 50 MPH...FREQUENT CLOUD TO GROUND LIGHTNING...BRIEF HEAVY
DOWNPOURS...ARE POSSIBLE WITH THESE STORMS.
ADDITIONAL ISOLATED THUNDERSTORMS WERE DEVELOPING FARTHER EAST INTO
SOUTHERN MCHENRY AND LAKE COUNTIES.
LOCATIONS IMPACTED INCLUDE...
POLO... FORRESTON... DURAND...
LAKE SUMMERSET... PECATONICA... MOUNT MORRIS...
WINNEBAGO... STILLMAN VALLEY... OREGON...
BYRON... ROSCOE... ROCKTON...
PRECAUTIONARY/PREPAREDNESS ACTIONS...
GUSTY WINDS MAY CAUSE SMALL BRANCHES TO BE BLOWN DOWN...AND LOOSE
OBJECTS TO BLOW AROUND. STAY AWAY FROM HIGH OBJECTS OUTDOORS SUCH AS
TREES. HEAVY RAINFALL CAN LEAD TO FLOODING OF LOW LYING AREAS SUCH AS
DITCHES...VIADUCTS...UNDERPASSES...CREEKS AND DRAINAGE AREAS. SEEK
SHELTER IN A STURDY STRUCTURE UNTIL THESE STORMS HAVE PASSED.
LAT...LON 4250 8896 4182 8896 4187 8964 4192 8963
4193 8969 4220 8970 4221 8940 4250 8940
RATZERPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1222 AM CDT SAT JUL 23 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1221 AM HAIL FORRESTON 42.13N 89.58W
07/23/2011 E0.25 INCH OGLE IL LAW ENFORCEMENT
PEA HAIL AND 30 TO 40 MPH WINDS. FROM OGLE COUNTY
SHERIFF.
&&
RATZERPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1246 AM CDT SAT JUL 23 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1242 AM TSTM WND GST MACHESNEY PARK 42.36N 89.04W
07/23/2011 E50 MPH WINNEBAGO IL TRAINED SPOTTER
SMALL BRANCHES DOWN.
&&
RATZERPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1247 AM CDT SAT JUL 23 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1243 AM FLOOD MACHESNEY PARK 42.36N 89.04W
07/23/2011 WINNEBAGO IL TRAINED SPOTTER
STREET FLOODING BEGINNING AT WINDSOR AND ROUTE 251.
&&
RATZERThe Chicago radar (KLOT), 39 km away, was scanning. The volume nearest the first event began at 05:53 UTC.
4 lightning, 3 flash flood, 1 thunderstorm wind. Local standard time, as filed.
A garage and three cars were destroyed when a massive burr oak tree was blown down along Forest Avenue. A house was heavily damaged on Franklin Avenue by a huge silver maple tree that was split in half.
Thunderstorms produced torrential rainfall across northern Cook County with rainfall rates between 2 and 4 inches per hour which caused widespread flash flooding. Chicago O'Hare Airport measured 6.78 inches of rain during a 3 hour period between 1251 am CDT and 351 am CDT, with 3.19 inches falling between 151 am CDT and 251 am CDT. This extreme rainfall which fell across much of northern Cook County caused widespread street, parking lot and basement flooding with numerous cars stranded and submerged. Retention ponds, creeks and small streams quickly overflowed their banks.
In Prospect Heights, a sewage lift station lost power for about 6 hours, causing the flooding to be worse in some areas. Some basements were completely flooded with flood water and sewage 8 to 10 feet deep. In Mt. Prospect, an estimated 100 vehicles were disabled in high water. Numerous roads and intersections were flooded with several feet of standing water. Two feet of water pooled in the underground parking garage of the Mt. Prospect Library. Some of this water seeped into the lower level lobby. In Park Ridge, nearly 500 basements were flooded along with numerous streets. In nearby unincorporated Maine Township, more than 500 residences and 175 businesses were affected by flooding. Hundreds of vehicles suffered some amount of flood damage with some vehicles completely covered by flood waters.
In Niles, more than 240 homes suffered some level of flooding with 5 to 6 feet of water in some basements. In Glenview, three manhole covers were blown off by the flood waters with numerous flooded streets. In Glencoe, numerous streets were flooded and impassible stranding dozens of cars. One motorist needed to be rescued from a vehicle. The basment of the Village Hall was also flooded. In Des Plaines, dozens of streets and basements were flooded. Some basements sustained as much as $10,000 in damages. One woman had to be rescued from her stranded car on Elmhurst Road. Fairgrounds in downtown Des Plaines were damaged by flood water. In Northbrook, four motorists had to be rescued from vehicles stranded in flood waters. In Elk Grove Village, almost every road had some amount of flooding during the height of the storm. At least one vehicle was stranded in flood waters on Morrison Boulevard.
In Rolling Meadows, the Carriageway area and Barker Lake areas were the hardest hit. Several streets were flooded with stranded and submerged vehicles. In Winnetka, numerous streets were flooded and impassible with stranded and submerged vehicles. Basement flooding was widespread. A sink hole developed near a large hackberry tree and the water rushing into the hole resembled a small waterfall. The tree began to lean over and was eventually cut down. The Winnetka Golf Club's 18 hole course was closed for 10 days due to flooding and is part of a floodplain, which is expected to provide stormwater detention after heavy rain. In Palatine, a 15 foot by 20 foot sinkhole developed at the northwest corner of Dundee and Hicks Road when a sewer line about 30 feet below the surface collapsed. In Arlington Heights, numerous streets and basements were flooded including the parking lot of the International Plaza. Several cars were stranded in the flood waters. The Arlington Heights Chamber of Commerce office in the basement of a bank was flooded. Flood water was reported to be a raging river which roared down Phelps Avenue in Arlington Heights. Damage to just one basement was estimated at $80,000.
Storm total rainfall amounts included 8.20 inches at Chicago O'Hare Airport; 7.25 inches in Arlington Heights; 7.17 inches in Elk Grove Village; 6.06 inches at the Wheeling/Chicago Excutive Airport and 5.33 inches in Northbrook.
Thunderstorms produced torrential rainfall across northeast Dupage County with rainfall rates between 2 and 4 inches per hour which caused flash flooding. Chicago O'Hare Airport measured 6.78 inches of rain during a 3 hour period between 1251 am CDT and 351 am CDT, with 3.19 inches falling between 151 am CDT and 251 am CDT. This extreme rainfall which fell across northeast Dupage County caused street, parking lot and basement flooding in some areas. Retention ponds, creeks and small streams quickly overflowed their banks. A Bensenville man was rescued after his vehicle became stuck when he drove into a flooded construction zone. Storm total rainfall amounts included 8.20 inches at Chicago O'Hare Airport; 3.68 inches in Villa Park; 3.60 inches in Glen Ellyn; 3.48 inches in Carol Stream; 2.86 inches in Oak Brook and 2.79 inches in Westmont.
Thunderstorms produced torrential rainfall across central and southeast Cook County with rainfall rates between 2 and 4 inches per hour which caused widespread flash flooding. Chicago O'Hare Airport measured 6.78 inches of rain during a 3 hour period between 1251 am CDT and 351 am CDT, with 3.19 inches falling between 151 am CDT and 251 am CDT. This extreme rainfall which fell across much of central Cook County caused widespread street, parking lot and basement flooding with numerous cars stranded and submerged. Retention ponds, creeks and small streams quickly overflowed their banks.
In Oak Park, at least 163 homes experenced basement flooding. In Elmwood Park, several feet of water covered Oak Leaf Avenue with numerous cars stranded in the flood waters. About eight cars were stalled out along 80th Avenue. In La Grange, numerous vehicles were stranded and stalled in flood waters, including one police car. The basement of the police station also flooded. In Norridge, numerous streets and basements were flooded. Several streets, underpasses and basements were flooded in and around Rosemont. Several vehicles appeared to have been piled up by flood waters along Mannheim Road near O'Hare Airport.
In Chicago, hundreds of basements, roads and viaducts were flooded. Some of the more significant reports included three semi trucks stranded in water more than 10 feet deep on Interstate 57 near 99th Street. One of the three drivers swam away. The other two drivers were rescued by boat. Lakeshore Drive was closed between Chicago and Congress. Interstate 94 was closed in both directions near 87th Street and northbound at 67th Street. Hundreds of vehicles were stranded or stalled in flood waters. Railroad tracks which service the Chicago Transportation Authority's Red, Blue and Pink lines were flooded. Several motorists need to be rescued from strand cars in flood waters on the Edens Expressway at Willow Road. The Metropolitan Water Reclamation District opened the locks at Wilmette and the Chicago River downtown, which allows untreated sewage and rain water to flow directly into Lake Michigan.
Storm total rainfall amounts included 8.20 inches at Chicago O'Hare Airport; 4.92 inches near Oak Park; 4.30 inches near Countryside and 4.00 inches in Melrose Park.
Lightning struck a house on Jackson Street which started a fire in the attic and on the second floor. Damage to the house was estimated at $75,000 and at $25,000 to its contents.
Lightning struck a large house on Lincoln Avenue and started a fire in the attic which spread to the second floor. The house and its contents were a total loss. No one was home at the time of the fire.
A church on Division Street was struck by lightning which broke a hole in the steeple tower. Much of the damage was from heavy rain which entered through the hole.
Lightning struck a 39 unit apartment building in Mt. Prospect. The fire quickly consumed the attic and 3rd floor. Fire departments were delayed by flooded roads. The building was a total loss and would be demolished with all 75 residents having to find a new place to live. Many of the residents lost all their belongings.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2011Every state in 2011This day in weather historyWarnings in Illinois, July 2011
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: 338129, 337359, 338128, 337369, 337374, 337999, 338000, 337373.