Strong to severe thunderstorms moved across parts of northern Illinois during the morning hours of June 27th.
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 moved across parts of northern Illinois during the morning hours of June 27th.
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 Jun 27, 5:54 AM CST, 2 hours 36 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 654 AM CDT SUN JUN 27 2010 .DISCUSSION... 323 AM CDT ONGOING CONVECTION THIS MORNING IS KNOCKING ON THE DOOR OF THE CWA IN THE FORM OF A DOUBLE BARRELED MCS OVER WISCONSIN AND IOWA. THE WISCONSIN PORTION OF THE CWA IS SHOWING SIGNS OF DEVELOPING AN MCV WHICH WILL TRACK EWD ACROSS LAKE MICHIGAN. THE LEADING EDGE CONVECTION EXTENDS FROM KOSH TO KMRJ AND IS SLOWLY MOVING SEWD. THE SRN PORTION OF THE LINE IS BEGINNING TO WEAKEN WITH AN OUTFLOW BOUNDARY MOVING OUT AHEAD OF THE MAIN CONVECTIVE LINE. EXPECT THAT THE LINE WILL WEAKEN BEFORE ENTERING THE NWRN PORTION OF THE CWA...BUT WILL HOLD ONTO SOME EARLY MORNING POPS AS THE LINE MAY MAINTAIN ENOUGH INTEGRITY TO BRING SOME SHOWERS AND THUNDERSTORMS TO THE NRN TIER COUNTIES. THE IOWA PORTION OF THE MCS MAY PROVE MORE PROBLEMATIC IN THE NEAR TERM. WHILE THE ERN PORTION OF THE AREA IS SHOWING SOME WEAKENING...THE CONVECTION OVER WRN IOWA IS STRENGTHENING. EXPECT THAT THIS SYSTEM WILL ALSO INDUCE DEVELOPMENT OF AN MCV WHICH SHOULD TRACK EWD...PROVIDING FOCUS FOR RENEWED THUNDERSTORM DEVELOPMENT OVER NRN ILLINOIS...AND EVENTUALLY INTO NWRN INDIANA. THE ENVIRONMENT OVER THE CWA IS PRIMED FOR THUNDERSTORM DEVELOPMENT WITH SFC DEWPOINTS IN THE LOW 70S AND PLENTY OF HEAT AS TEMPERATURES ARE ONCE AGAIN EXPECTED TO REACH INTO THE UPPER 80S TO LOW 90S. AND WHILE HEAT INDEX VALUES WILL ONCE AGAIN FLIRT WITH THE 100 DEGREE MARK...THUNDERSTORMS WILL BE THE PRIMARY CONCERN FOR TODAY. MODEL WIND PROFILES ACROSS THE AREA INDICATE A MODERATE WSWLY LOW LEVEL WIND MAX WITH 35KT AT 850-800MB AND WEAK BACKING OF WINDS WITH HEIGHT FROM THE SWLY SFC WINDS. ENOUGH DIRECTIONAL SHEAR WILL BE IN PLACE TO PROVIDE A RISK FOR SOME STORMS TO REACH SEVERE LEVELS. THE PRIMARY THREAT WILL BE STRONG...DAMAGING WINDS. LARGE HAIL WILL ALSO BE A POSSIBILITY...BUT GIVEN A FREEZING LEVEL OF 15.5KFT ON THE 00Z ILX SOUNDING...THIS WILL BE A SECONDARY CONCERN. THE WARM...MOIST...UNSTABLE AIRMASS WILL REMAIN IN PLACE UNTIL THE NEXT UPSTREAM COLD FRONT CAN SCOUR OUT THE AREA. THIS MORNING...THE FRONT EXTENDS FROM A WEAK LOW IN NWRN IOWA THROUGH CNTRL NEBRASKA. THE MODELS ARE IN RELATIVELY GOOD AGREEMENT ON THE TIMING OF MOVEMENT OF THIS FRONT...PUSHING IT INTO NWRN IL BY LATE THIS EVENING. AS THE FRONT PUSHES EWD...PCPN/TSTM CHANCES WILL CLEAR FROM NORTHWEST TO SOUTHEAST...WITH THE LAST PCPN MOVING OUT OF THE SERN PORTIONS OF THE CWA BY EARLY MONDAY MORNING. LOOKING INTO THE LONGER TERM...THE REGION WILL SEE A COOLING TREND AS COOLER/DRIER AIR FILTERS IN BEHIND THE FRONT. FROM TUESDAY THROUGH THURSDAY...HIGH TEMPERATURES WILL BE ONLY IN THE UPPER 70S TO LOWER 80S AND CHANCES FOR ANY PCPN WILL BE QUITE LOW. BY THE END OF THE WEEK...UPPER RIDGING WILL BUILD OVER THE MIDWEST WITH TEMPERATURES RETURNING BACK INTO THE UPPER 80S AND LOWER 90S. KREIN KREIN && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 12Z... CONCERNS FOR THE CHICAGO TERMINALS THIS MORNING INCLUDE AN OUTFLOW BOUNDARY MOVING TOWARDS ORD AROUND 12Z. THIS BOUNDARY COULD BRIEFLY TURN WINDS TO BE OUT OF THE NORTH. AN AREA OF THUNDERSTORMS CURRENTLY STRENGTHENING ACROSS WESTERN ILLINOIS IS EXPECTED TO IMPACT THE TERMINALS AROUND 14 TO 15Z LATER THIS MORNING. BMD //DISCUSSION...UPDATED 12Z... LINE OF THUNDERSTORMS THAT WAS PREVIOUSLY IN THE FORECAST TO AFFECT THE CHICAGO TERMINALS AROUND 12Z HAS WEAKENED SIGNIFICANTLY. AN OUTFLOW BOUNDARY REMAINS MAKING ITS WAY SOUTH TOWARDS ORD AND DPA AROUND 12Z. WINDS ON THE NORTH SIDE OF THE BOUNDARY HAVE BEEN GUSTING BRIEFLY OUT OF THE NORTH BETWEEN 15 TO 20 KTS AND CEILINGS HAVE DROPPED TO AROUND 2K FT...HOWEVER THERE IS UNCERTAINTY IN HOW FAR SOUTH THIS BOUNDARY WILL TRAVEL. THUNDERSTORMS CONTINUE TO THE WEST OF THE TERMINALS OVER EASTERN IOWA WITH AN AREA OF CONVECTION FIRING AHEAD OF THE LINE IN NORTHWEST AND WEST CENTRAL ILLINOIS. THESE STORMS EXPECTED TO NEAR THE CHICAGO TERMINALS AROUND 15Z LATER THIS MORNING. OTHER THAN BRIEF NORTHERLY WINDS ON THE NORTH SIDE OF THE AFOREMENTIONED OUTFLOW BOUNDARY...WINDS ARE EXPECTED TO BE GUSTY OUT OF THE SOUTHWEST THROUGH THIS EVENING. A COLD FRONT IS EXPECTED TONIGHT AND WINDS WILL START TO SHIFT TO THE WEST THEN NORTHWEST LATE TONIGHT. BEHIND THE FRONT...HIGH PRESSURE IS EXPECTED TO BUILD IN WITH VFR CONDITIONS AND NORTHWESTERLY FLOW. BMD //ORD AND MDW CONFIDENCE...UPDATED 12Z... HIGH CONFIDENCE ON WIND DIRECTION AND SPEED OUTSIDE OF THUNDERSTORMS. MEDIUM CONFIDENCE IN TIMING OF AFTERNOON CONVECTION. LOW CONFIDENCE IN COVERAGE. BMD //OUTLOOK FOR ORD/MDW FOR 18Z MONDAY-12Z FRIDAY...UPDATED 06Z... MONDAY...SLT CHC TSRA. VFR. TUESDAY...VFR. WEDNESDAY...VFR. THURSDAY...VFR. FRIDAY...VFR. && .MARINE... 301 AM CDT MARINE CONCERNS FOR THE NEXT FEW DAYS WILL BE GUSTY WINDS AS WELL AS SHOWERS AND THUNDERSTORMS THIS AFTERNOON. A LOW PRESSURE SYSTEM CURRENTLY OVER MINNESOTA WILL LIFT TO THE NORTHEAST TODAY AND THE ATTENDANT COLD FRONT IS EXPECTED TO BRING SHOWERS AND THUNDERSTORMS TO THE AREA LATER THIS AFTERNOON. SOUTHWESTERLY WINDS AHEAD OF THE FRONT ARE EXPECTED TO GUST INTO THE 20 TO 25 KT RANGE THIS AFTERNOON. OVER THE OPEN WATERS...WARM ADVECTION OVER COOLER LAKE WATERS SHOULD LIMIT GUST POTENTIAL SOMEWHAT WITH LAKE GENERATED STABILITY. THE LOW PRESSURE SYSTEM WILL EXIT TO THE NORTHEAST LATE SUNDAY WHILE A LOW PRESSURE TROUGH IS EXPECTED TO MOVE OVER UPPER PENINSULA MICHIGAN DURING THE DAY MONDAY. THIS WILL AGAIN INCREASE THE WINDS WITH THE STRONGEST GUSTS OVER THE NORTHERN HALF OF THE LAKE AND AGAIN GUSTS TO AROUND 25 KTS ARE EXPECTED. BY WEDNESDAY HIGH PRESSURE IS EXPECTED TO BEGIN BUILDING INTO THE AREA. THIS WILL RESULT IN DRY CONDITIONS WITH LIGHT WINDS THROUGH THE REMAINDER OF THE WEEK. BMD && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 450 AM CDT SUN JUN 27 2010 ILZ003>006-008-010>014-019>023-032-033-039-INZ001-002-010-011-019- 281000- 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- 450 AM CDT SUN JUN 27 2010 /550 AM EDT SUN JUN 27 2010/ THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL ILLINOIS... NORTHEAST ILLINOIS AND NORTHWEST INDIANA. .DAY ONE...TODAY AND TONIGHT. WEATHER HAZARDS EXPECTED: THUNDERSTORMS....SOME COULD PRODUCE: WIND GUSTS TO 60 MPH. HAIL UP TO THE SIZE OF QUARTERS. AREAS AFFECTED AND TIMING: THE ENTIRE OUTLOOK AREA. WHILE SCATTERED THUNDERSTORMS ARE POSSIBLE BEFORE NOON...THE GREATER CHANCE FOR THE STRONGEST THUNDERSTORMS WILL BE FROM THE LATE AFTERNOON THROUGH THE EVENING HOURS. A COLD FRONT PUSHING THROUGH THE REGION TONIGHT WILL ALLOW THE THREAT OF THUNDERSTORMS TO COME TO AN END...GRADUALLY FROM THE NORTHWEST TO THE SOUTHEAST. UNTIL THE FRONT CLEARS THE AREA LATE TONIGHT...THERE WILL BE A LINGERING CHANCE OF THUNDERSTORMS FOR THE SOUTHEASTERN PORTIONS OF THE OUTLOOK AREA THROUGH THE EARLY MORNING HOURS. DISCUSSION: A MID LEVEL DISTURBANCE GENERATED BY EARLY MORNING CONVECTIVE ACTIVITY OVER IOWA WILL TRACK EASTWARD THROUGH NORTHERN ILLINOIS AND INTO NORTHERN INDIANA TODAY. THE ENVIRONMENT IS PRIMED FOR THUNDERSTORM DEVELOPMENT WITH SURFACE DEWPOINTS IN THE LOW 70S AND TEMPERATURES EXPECTED TO REACH INTO THE UPPER 80S TO LOWER 90S. THE LOW LEVEL WIND PROFILE SUGGESTS THAT THE GREATEST THREAT WILL BE DAMAGING WIND GUSTS WITH A SECONDARY THREAT FOR LARGE HAIL. SINCE THE GROUND IS STILL WET AND TREES MAY BE WEAKENED BY RECENT STORMS...ADDITIONAL TREE DAMAGE IS A STRONG POSSIBILITY... EVEN FROM SUB-SEVERE STORMS WITH STRONG WIND GUSTS. PORTIONS OF THE ILLINOIS RIVER WILL REMAIN IN FLOOD. PORTIONS OF THE KANKAKEE...IROQUOIS AND FOX RIVERS WILL BE BANKFULL. THUNDERSTORMS TODAY WILL ALSO HAVE THE POTENTIAL TO PRODUCE HEAVY RAINFALL WITH AMOUNTS OF 1 TO 2 INCHES AND LOCALLY HIGHER AMOUNTS. AREA STREAMS AND RIVERS THAT ARE NEAR BANKFULL WILL LIKELY SEE RISES WITH ADDITIONAL FLOODING POSSIBLE. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. PORTIONS OF THE ILLINOIS RIVER WILL REMAIN IN FLOOD. PORTIONS OF THE KANKAKEE...IROQUOIS AND FOX RIVERS WILL BE BANKFULL. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NECESSARY THIS AFTERNOON AND TONIGHT. && COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO WEBPAGE: WEATHER.GOV/CHICAGO LMZ740>745-281000- 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- 450 AM CDT SUN JUN 27 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE ILLINOIS NEARSHORE WATERS OF LAKE MICHIGAN AND THE INDIANA NEARSHORE WATERS OF LAKE MICHIGAN. .DAY ONE...TODAY AND TONIGHT. THUNDERSTORMS ARE LIKELY FOR THE AFTERNOON AND EVENING HOURS. SOME STORMS MAY PRODUCE STRONG WIND GUSTS IN EXCESS OF 35 KNOTS. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. && 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- 870-872-874-876-878-281000- 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 TOW 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- 450 AM CDT SUN JUN 27 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE OPEN WATERS OF LAKE MICHIGAN. .DAY ONE...TODAY AND TONIGHT. THUNDERSTORMS ARE LIKELY THIS AFTERNOON AND TONIGHT. SOME STORMS MAY PRODUCE STRONG WIND GUSTS IN EXCESS OF 35 KNOTS. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. && COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO WEBPAGE: WEATHER.GOV/CHICAGO KREIN
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
856 AM CDT SUN JUN 27 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0845 AM HEAVY RAIN GENOA 42.10N 88.69W
06/27/2010 M1.96 INCH DE KALB IL CO-OP OBSERVER
RAIN FELL BETWEEN 8 AM AND 845 AM CDT. STREETS WERE
FLOODED.
&&PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
913 AM CDT SUN JUN 27 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0855 AM HEAVY RAIN 4 W HUNTLEY 42.18N 88.51W
06/27/2010 M1.30 INCH MCHENRY IL TRAINED SPOTTER
RAIN OCCURRED IN THE PAST 30 MINUTES.
&&
ACSSPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 925 AM CDT SUN JUN 27 2010 ILZ014-022-023-033-INZ001-010-271445- COOK IL-IROQUOIS IL-KANKAKEE IL-LAKE IN-NEWTON IN-WILL IL- 925 AM CDT SUN JUN 27 2010 ...STRONG THUNDERSTORMS WILL AFFECT KANKAKEE...NORTHEASTERN IROQUOIS...NORTHWESTERN NEWTON...EXTREME SOUTH CENTRAL COOK...SOUTHERN WILL AND SOUTHWESTERN LAKE COUNTIES... AT 925 AM CDT...STRONG THUNDERSTORMS WERE ALONG A LINE FROM WILMINGTON TO WATSEKA...MOVING NORTHEAST AT 45 MPH. WIND GUSTS TO 50 MPH ARE POSSIBLE WITH THESE STORMS. VERY HEAVY RAIN WILL FALL FROM THESE STORMS...AND WILL CAUSE WATER TO POND ON ROADS AND QUICKLY FILL ROADSIDE DITCHES AND SMALL STREAMS. THESE STORMS WILL BE NEAR MANHATTAN...PAPINEAU...MARTINTON...AND BRADLEY AROUND 930 AM...SUN RIVER TERRACE...ST. ANNE...MANTENO...AND BEAVERVILLE AROUND 935 AM...PEOTONE AND MOMENCE AROUND 940 AM. LAT...LON 4152 8765 4099 8740 4079 8784 4140 8821 MARSILI
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
925 AM CDT SUN JUN 27 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0920 AM HEAVY RAIN 5 SW WAUCONDA 42.23N 88.22W
06/27/2010 M0.94 INCH MCHENRY IL TRAINED SPOTTER
AMOUNT OF RAIN THE IN PAST 30 MINUTES. COCORAHS OBSERVER.
&&
ACSThe Chicago radar (KLOT), 56 km away, was scanning. The volume nearest the first event began at 14:28 UTC.
1 thunderstorm wind, 1 flash flood. Local standard time, as filed.
Tree limbs were blown down with estimated wind gusts to 60 mph.
Thunderstorms produced heavy rain on the south side of Chicago and surrounding suburban Cook County. Rainfall reports ranged from 1.5 inches near Chicago Ridge to 2.47 inches near Beverly. The heavy rain caused basement flooding in 241 homes, mainly between 83rd Street and 112th Street. Some specific spots where flooding was reported included 108th and Talman, 100th and Campbell, 112th and Campbell, 107th and Troy, 94th and Damen, and 95th and Cottage Grove. Part of the Dan Ryan Expressway was closed from 83rd to the Bishop Ford Expressway. Cars were stranded in railroad viaducts.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2010Every state in 2010This day in weather historyWarnings in Illinois, June 2010
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: 236249, 243605.