During the morning hours of July 11, 2011, a line of severe thunderstorms moved very quickly across northern Illinois and southern Lake Michigan, producing widespread wind damage.  In addition, the strong thunderstorm winds with this system generated a classic seiche event on the lake.  A seiche is a situation where lake water ahead of the storms is piled up along the downstream shore (in this case Indiana and Michigan) and then sloshes back and forth across the lake for several hours.  The danger from a seiche comes from rapidly rising and falling lake levels, which can damage watercraft along the shoreline, sweep people off piers and breakwaters, and pull swimmers far away from shore.

The storms responsible for this event developed late Sunday into early Monday across Nebraska and western Iowa.  Overnight they produced extensive wind damage across much of Iowa.  By 6:00 AM CDT as they moved into Illinois, a very moist unstable airmass (MLCAPE of 2000-4000 J/Kg) with considerable deep layer wind shear (40-50 kts) was in place ahead of the storms.  The Craven/Brooks Significant Severe Parameter, which represents the contribution from both MLCAPE and deep layer shear, was showing values as high as 60,000 m3/s3 (while normally values around 20,000 are considered sufficient for significant severe storms).

 11z Craven Brooks SigSvr
2011 July 11 -- 11Z Craven Brooks SigSvr Parameter

 

While the wind shear was sufficient to support organized severe storms, the westerly unidirectional nature of the winds was more conducive to the development of strong straight line wind damage versus tornadoes.  Despite the lack of directional shear, or actually because of it, the strong mid and upper-level winds were able to mix down to the surface and produce a wide swath of 60-80 mph measurements -- plus the associated damage.

This thunderstorm complex fit the description of a bow echo "derecho" which is a widespread, long-lived windstorm that is associated with a band of rapidly moving showers or thunderstorms.  The term bow echo refers to the arched, bow-like structure of the thunderstorm complex seen in the radar reflectivity data below. The same thunderstorm complex that produced widespread wind damage in the Central Plains and Midwest actually was able to persist all the way to nearly the Delmarva Peninsula in the Mid Atlantic, producing a swath of nearly continuous swath of wind damage along its path.

For more information on derechos, please refer to the Storm Prediction Center web page, About Derechos. Following the derecho categories on the SPC page, yesterday's system can be classified as a "progressive derecho."

13z radar and 850-300 mean wind

2011 July 11 -- 13Z Mean wind from 850-300mb

 

path of derecho from Nebraska to the East Coast
Complete path of the derecho from Nebraska to the East Coast on 10-11 July 2011

 

The effects of the seiche with this system were most readily visible from the water level measurements at the Calumet Harbor data collection platform.  The following image shows the weather conditions prior to, during, and after the passage of the line of thunderstorms.  The top graph shows water levels starting to fluctuate considerably soon after the line passed, eventually with over 2 feet of difference from peak to trough.

Calumet Harbor weather obs for 2011 July 11

 

Finally, here is a summary of the local area severe weather reports received from these storms (thru 3 PM CDT on July 11):

PRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
201 PM CDT TUE JUL 12 2011

..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..

0645 AM TSTM WND DMG 2 NE NELSON 41.82N 89.58W
07/11/2011 LEE IL EMERGENCY MNGR

CORN FLATTENED NEAR HARMON AND ROCK ISLAND RD.

0700 AM TSTM WND GST LOVES PARK 42.34N 89.01W
07/11/2011 E70.00 MPH WINNEBAGO IL TRAINED SPOTTER

SEMI OVERTURNED. WINDS SUSTAINED FOR SEVERAL MINUTES.

0700 AM HEAVY RAIN 2 ENE ROCKFORD 42.28N 89.03W
07/11/2011 M0.75 INCH WINNEBAGO IL 911 CALL CENTER

0700 AM TSTM WND GST WINNEBAGO 42.27N 89.24W
07/11/2011 E60.00 MPH WINNEBAGO IL BROADCAST MEDIA

ESTIMATED WIND GUST OUTSIDE WREX STUDIO.

0700 AM HEAVY RAIN 1 ENE ROCKFORD 42.28N 89.04W
07/11/2011 E0.75 INCH WINNEBAGO IL COCORAHS

STORM TOTAL

0705 AM TSTM WND GST ROCKFORD 42.27N 89.06W
07/11/2011 M55.00 MPH WINNEBAGO IL AMATEUR RADIO

MEASURED AT 6TH AND BROADWAY.

0705 AM TSTM WND GST ROCKFORD 42.27N 89.06W
07/11/2011 M50.00 MPH WINNEBAGO IL AMATEUR RADIO

BYPASS 20 AND 11TH STREET.

0709 AM TSTM WND GST FRANKLIN GROVE 41.84N 89.30W
07/11/2011 E70.00 MPH LEE IL TRAINED SPOTTER

12 INCH DIAMETER TREES DOWN.

0710 AM TSTM WND DMG 7 SE BELVIDERE 42.18N 88.75W
07/11/2011 BOONE IL BROADCAST MEDIA

POWER LINES DOWN BLOCKING EASTBOUND LANES OF INTERSTATE
90 AT COUNTY LINE ROAD ON BOONE AND MCHENRY COUNTY LINE.


0710 AM TSTM WND DMG CRESTON 41.93N 88.97W
07/11/2011 OGLE IL TRAINED SPOTTER

2 LARGE TREES BLOWN DOWN - 3 TELEPHONE POLES SEVERELY
LEANING - CORN IN THE AREA FLATTENED. HALF WAY BETWEEN
CRESTON AND MALTA, N SIDE OF IL-38, METAL BARN BLOWN
OVER.

0710 AM TSTM WND DMG 5 SW POLO 41.93N 89.65W
07/11/2011 OGLE IL 911 CALL CENTER

CORN FIELDS LAYING FLAT AND BRANCHES 6 INCHES IN DIAMETER
DOWN ALONG WITH POWER LINES.

0715 AM TSTM WND GST ROCKFORD 42.27N 89.06W
07/11/2011 E80.00 MPH WINNEBAGO IL PUBLIC

70 TO 80 MPH WINDS TRANSFORMERS DAMAGED CAUSING POWER
OUTAGE AND SEMI BLOWN ON SIDE.

0715 AM TSTM WND GST ROCKFORD 42.27N 89.06W
07/11/2011 E80.00 MPH WINNEBAGO IL TRAINED SPOTTER

ESTIMATED 70 TO 80 MPH WINDS ON EAST SIDE OF ROCKFORD.

0715 AM TSTM WND DMG 2 SW COMPTON 41.67N 89.11W
07/11/2011 LEE IL EMERGENCY MNGR

ROUNT 251 BLOCKED BY DOWNED POWER LINES NEAR SPURR RD.

0715 AM TSTM WND DMG 2 SW COMPTON 41.67N 89.11W
07/11/2011 LEE IL EMERGENCY MNGR

RT 251 BLOCKED BY DOWN POWER LINES NEAR SPURR RD.

0717 AM TSTM WND DMG POPLAR GROVE 42.37N 88.82W
07/11/2011 BOONE IL BROADCAST MEDIA

OVER 30 LARGE TREES DOWN. RELAYED BY WREX.

0717 AM TSTM WND DMG POPLAR GROVE 42.37N 88.82W
07/11/2011 BOONE IL BROADCAST MEDIA

MULTIPLE REPORTS OF TREES DOWN IN CANDLEWICK LAKE.
RELAYED BY WREX.

0720 AM TSTM WND DMG DE KALB 41.93N 88.75W
07/11/2011 DE KALB IL EMERGENCY MNGR

TREES SNAPPED OFF AT THE BASE AT ANNIE GLIDDEN RD SOUTH

OF RT 38. CORN ALSO FLATTENED NORTH AND SOUTH OF DE KALB.

0720 AM TSTM WND DMG POPLAR GROVE 42.37N 88.82W
07/11/2011 BOONE IL TRAINED SPOTTER

ROOF BLOWN OFF OF HOUSE. GARAGE ALSO DESTROYED.

0726 AM TSTM WND GST 10 W ROCKFORD 42.27N 89.26W
07/11/2011 E55.00 MPH WINNEBAGO IL TRAINED SPOTTER

SUSTAINED WINDS AT 40 TO 45 MPH. FREQUENT CG LIGHTNING.
DITCHES STARTING TO FILL WITH WATER.

0728 AM TSTM WND GST 6 NNE ROCKFORD 42.35N 89.02W
07/11/2011 E60.00 MPH WINNEBAGO IL TRAINED SPOTTER

SUSTAINED WIND AT 40 TO 45 MPH. POWER OUTAGES REPORTED.

0728 AM TSTM WND GST NW DE KALB 41.93N 88.75W
07/11/2011 E70.00 MPH DE KALB IL TRAINED SPOTTER

TREES SNAPPING.

0730 AM TSTM WND DMG HARVARD 42.42N 88.62W
07/11/2011 MCHENRY IL TRAINED SPOTTER

NUMEROUS TREES AND POWER LINES DOWN. ONE TREE FELL ON A
HOUSE.

0730 AM TSTM WND DMG ROCKFORD 42.27N 89.06W
07/11/2011 WINNEBAGO IL EMERGENCY MNGR

LARGE TREE DOWN THAT TOOK DOWN SOME POWER LINES. STATE ST
CLOSED FROM 9TH TO DIVISION.

0730 AM TSTM WND DMG HARVARD 42.42N 88.62W
07/11/2011 MCHENRY IL TRAINED SPOTTER

DELAYED REPORT. E60 MPH. NUMEROUS 12 INCH DIAMETER TREES
DOWN. TREES WERE SNAPPED OFF CLEAN APPROXIMATELY 30 FEET
HIGH.

0730 AM TSTM WND GST SYCAMORE 41.98N 88.70W
07/11/2011 E60.00 MPH DEKALB IL TRAINED SPOTTER

0735 AM TSTM WND DMG LAKE IN THE HILLS 42.19N 88.32W
07/11/2011 MCHENRY IL PUBLIC

IN THE MEADOWBROOK NEIGHBORHOOD THERE ARE NUMEROUS HOUSES
WITH THE SIDING RIPPED OFF. MULTIPLE TREES ARE UPROOTED
OR SNAPPED AT THE BASE. ONE HOUSE ON WATERFORD LANE HAD
THE CHIMNEY BLOWN OFF.

0735 AM TSTM WND GST ELBURN 41.89N 88.47W
07/11/2011 M65.00 MPH KANE IL TRAINED SPOTTER

MEASURED WITH ANEMOMETER. TREE BLOWN DOWN BEITH ROAD 1
MILE EAST OF RT. 47.

0735 AM TSTM WND GST SUGAR GROVE 41.77N 88.46W
07/11/2011 M60.00 MPH KANE IL ASOS

MEASURED AT AURORA AIRPORT.

0740 AM TSTM WND GST CRYSTAL LAKE 42.23N 88.33W
07/11/2011 E75.00 MPH MCHENRY IL TRAINED SPOTTER

GREATER THAN 70 MPH WINDS FOR 2 TO 3 MINUTES. POWER
OUTAGES. 1 FT DIAMETER TREES AND LARGE BRANCHES DOWN.

0747 AM TSTM WND GST CAROL STREAM 41.92N 88.13W
07/11/2011 E60.00 MPH DUPAGE IL PUBLIC

TRANSFORMER DAMAGED WITH POWER OUTAGE

0748 AM TSTM WND DMG YORKVILLE 41.64N 88.45W
07/11/2011 KENDALL IL PUBLIC

4 TO 5 INCH DIAMETER TREE BLOWN OVER. ESTIMATED WINDS OF
55 MPH.

0750 AM TSTM WND GST WARRENVILLE 41.82N 88.19W
07/11/2011 E60.00 MPH DUPAGE IL TRAINED SPOTTER

SUSTAINED 40 TO 50 MPH WINDS.

0750 AM TSTM WND GST WARRENVILLE 41.82N 88.19W
07/11/2011 E70.00 MPH DUPAGE IL TRAINED SPOTTER

60 TO 70 MPH GUSTS AND HEAVY RAIN.

0750 AM TSTM WND DMG ARLINGTON HEIGHTS 42.09N 87.98W
07/11/2011 COOK IL TRAINED SPOTTER

NEAR HINTZ RD AND WINDSOR THERE ARE FENCES BLOWN DOWN AND
AN 8 IN DIAMETER TREE SNAPPED.

0750 AM TSTM WND DMG WOODSTOCK 42.31N 88.44W
07/11/2011 MCHENRY IL PUBLIC

TREES DOWN WITH POWER OUTAGES.

0750 AM TSTM WND GST SUGAR GROVE 41.77N 88.46W
07/11/2011 M64.00 MPH KANE IL ASOS

MEASURED AT AURORA AIRPORT.

0750 AM TSTM WND GST N HOFFMAN ESTATES 42.06N 88.14W
07/11/2011 E60.00 MPH COOK IL TRAINED SPOTTER

INTERMITTANT POWER FAILURES.

0750 AM TSTM WND DMG ARLINGTON HEIGHTS 42.09N 87.98W
07/11/2011 COOK IL PUBLIC

AT THE RACE TRACK 4 TO 6 INCH BRANCHES DOWN. NUMEROUS
TREES AND WIRES DOWN. WINDS ESTIMATED TO 70 MPH.

0750 AM TSTM WND DMG FOX LAKE 42.42N 88.18W
07/11/2011 LAKE IL TRAINED SPOTTER

NUMEROUS TREE LIMBS UP TO 8 INCHES IN DIAMETER DOWN.

0751 AM TSTM WND GST ARLINGTON HEIGHTS 42.09N 87.98W
07/11/2011 E60.00 MPH COOK IL TRAINED SPOTTER

WINDOW BLOWN OUT OF A HOUSE. NUMEROUS TREE BRANCHES DOWN.


0751 AM TSTM WND DMG ELGIN 42.04N 88.29W
07/11/2011 KANE IL TRAINED SPOTTER

3 TO 4 INCH DIAMETER TREE LIMBS SNAPPED.

0752 AM TSTM WND GST LIBERTYVILLE 42.28N 87.97W
07/11/2011 M60.00 MPH LAKE IL TRAINED SPOTTER

0752 AM TSTM WND GST AURORA 41.77N 88.29W
07/11/2011 E70.00 MPH KANE IL TRAINED SPOTTER

0754 AM TSTM WND GST MUNDELEIN 42.27N 88.00W
07/11/2011 M72.00 MPH LAKE IL TRAINED SPOTTER

LOTS OF LIMBS UP TO 4 INCHES IN DIAMETER DOWN. SOME LARGE
TREES SNAPPED BLOCKING ROADS.

0754 AM TSTM WND GST OSWEGO 41.70N 88.33W
07/11/2011 M60.00 MPH KENDALL IL TRAINED SPOTTER

0755 AM TSTM WND DMG NAPERVILLE 41.76N 88.15W
07/11/2011 DUPAGE IL BROADCAST MEDIA

LARGE TREES DOWN IN PARTS OF NAPERVILLE. RELAYED BY FOX
CHICAGO.

0755 AM NON-TSTM WND GST NAPERVILLE 41.76N 88.15W
07/11/2011 E65.00 MPH DUPAGE IL 911 CALL CENTER

TREE LIMBS DOWN.

0755 AM TSTM WND DMG WEST DUNDEE 42.10N 88.29W
07/11/2011 KANE IL PUBLIC

LARGE TREE LIMBS DOWN.

0755 AM TSTM WND DMG NAPERVILLE 41.76N 88.15W
07/11/2011 DUPAGE IL TRAINED SPOTTER

TRAFFIC LIGHT DOWN AT NAPERVILLE RD.

0755 AM TSTM WND GST NAPERVILLE 41.76N 88.15W
07/11/2011 E65.00 MPH DUPAGE IL TRAINED SPOTTER

TREES BLOWN OVER.

0756 AM TSTM WND DMG PALATINE 42.11N 88.04W
07/11/2011 COOK IL TRAINED SPOTTER

12 INCH TREE FELL ON A HOUSE NEAR THE INTERSECTION OF
WINDSER AND PALITINE RD. AN 18 INCH TREE WAS ALSO
UPROOTED NEARBY. TIME ESTIMATED BASED ON RADAR.

0758 AM TSTM WND GST WINFIELD 41.87N 88.15W
07/11/2011 E60.00 MPH DUPAGE IL TRAINED SPOTTER

0759 AM TSTM WND GST AURORA 41.77N 88.29W
07/11/2011 E60.00 MPH KANE IL TRAINED SPOTTER

0800 AM TSTM WND GST CREST HILL 41.57N 88.11W
07/11/2011 E60.00 MPH WILL IL TRAINED SPOTTER

DELAYED REPORT. SHED WALLS BLOWN IN AND SEVERAL LARGE
BRANCHES DOWN.

0800 AM TSTM WND DMG EVANSTON 42.05N 87.69W
07/11/2011 COOK IL TRAINED SPOTTER

24 INCH DIAMETER TREE DOWN AT THE INTERSECTION OF OAKTON
AND WESLEY. OTHER TREES DOWN AS WELL.

0800 AM TSTM WND DMG 3 S LIBERTYVILLE 42.24N 87.97W
07/11/2011 LAKE IL PUBLIC

TELEPHONE LINES DOWN ALONG WITH LARGE TREES IN PRAIRIE
VIEW. A ROOF IS ALSO REPORTED TO BE BLOWN OFF.

0800 AM TSTM WND DMG OAK PARK 41.89N 87.79W
07/11/2011 COOK IL TRAINED SPOTTER

1 FOOT DIAMETER BRANCH DOWNED WITH NUMEROUS SMALLER
BRANCHES DOWN. HARVARD ST BETWEEN EAST AND CLARENCE.

0801 AM TSTM WND GST LIBERTYVILLE 42.28N 87.97W
07/11/2011 M70.00 MPH LAKE IL TRAINED SPOTTER

0801 AM TSTM WND GST GURNEE 42.38N 87.94W
07/11/2011 E70.00 MPH LAKE IL TRAINED SPOTTER

15 INCH TREE UPROOTED.

0802 AM TSTM WND GST DOWNERS GROVE 41.80N 88.02W
07/11/2011 E54.00 MPH DUPAGE IL PUBLIC

0802 AM TSTM WND DMG DOWNERS GROVE 41.80N 88.02W
07/11/2011 DUPAGE IL PUBLIC

18 TO 24 INCH TREE BRANCHES DOWN.

0804 AM TSTM WND GST AURORA 41.77N 88.29W
07/11/2011 E50.00 MPH KANE IL TRAINED SPOTTER

MANY LARGE BRANCHES DOWN.

0804 AM TSTM WND GST OHARE AIRPORT 41.98N 87.90W
07/11/2011 M63.00 MPH COOK IL ASOS

0805 AM TSTM WND DMG LISLE 41.79N 88.09W
07/11/2011 DUPAGE IL TRAINED SPOTTER

LARGE TREE BRANCHES DOWN.

0805 AM TSTM WND DMG GLEN ELLYN 41.87N 88.06W
07/11/2011 DUPAGE IL TRAINED SPOTTER

POWER OUTAGES

0805 AM TSTM WND DMG DOWNERS GROVE 41.80N 88.02W
07/11/2011 DUPAGE IL AMATEUR RADIO

POWER LINES DOWN ALONG WITH NUMEROUS TREE BRANCHES. 63RD
ST IS BLOCKED FROM FAIR VIEW TO BELMONS

0806 AM TSTM WND DMG SUMMIT 41.78N 87.82W
07/11/2011 COOK IL TRAINED SPOTTER

5 TO 6 DIAMETER LIMBS DOWN ALONG 62ND ST WITH A 20 INCH
DIAMETER TREE SPLIT VERTICALLY DOWN THE MIDDLE.

0806 AM TSTM WND DMG LONG GROVE 42.20N 88.00W
07/11/2011 LAKE IL TRAINED SPOTTER

2 FOOT DIAMETER TREES SNAPPED OFF AND UTILITY POLES DOWN
AT THE INTERSECTION OF CHECKER AND SCHAEFER IN LONG
GROVE.

0807 AM TSTM WND DMG ROGERS PARK 42.01N 87.67W
07/11/2011 COOK IL BROADCAST MEDIA

AT LEAST SIX LARGE TREES BLOWN DOWN IN LOYOLA PARK
SECTION OF ROGERS PARK NEAR THE LAKEFRONT. ESTIMATED 18
TO 24 INCH DIAMETER TREES. AT LEAST 65 MPH WIND GUSTS
ESTIMATED.

0807 AM TSTM WND DMG LINDENHURST 42.42N 88.03W
07/11/2011 LAKE IL TRAINED SPOTTER

UTILITY POLES SNAPPED OFF AND 6 TO 8 FOOT LONG AND 2 TO 4
INCHES IN DIAMETER.

0808 AM TSTM WND DMG MUNDELEIN 42.27N 88.00W
07/11/2011 LAKE IL TRAINED SPOTTER

2 TO 4 INCH DIAMETER LIMBS DOWN AT THE INTERSECTION OF RT
83 AND RT 45.

0809 AM TSTM WND GST PLAINFIELD 41.62N 88.20W
07/11/2011 E65.00 MPH WILL IL TRAINED SPOTTER

AT RT 59 AND CATON RD

0810 AM TSTM WND GST MELROSE PARK 41.90N 87.86W
07/11/2011 E60.00 MPH COOK IL TRAINED SPOTTER

0810 AM TSTM WND DMG WADSWORTH 42.44N 87.92W
07/11/2011 LAKE IL TRAINED SPOTTER

15 FOOT LONG BRANCHES DOWN ABOUT 4 TO 6 INCHES IN
DIAMETER NEAR WADSWORTH RD AND DELANEY RD.

0810 AM TSTM WND GST 6 SSE BEACH PARK 42.35N 87.81W
07/11/2011 M47.00 MPH LMZ740 IL C-MAN STATION

MEASURED AT WAUKEGAN HARBOR STATION.

0811 AM TSTM WND DMG LAKE ZURICH 42.19N 88.09W
07/11/2011 LAKE IL TRAINED SPOTTER

BRANCHES 6 TO 8 INCHES IN DIAMETER DOWN AT THE
INTERSECTION OF MILLER ROAD AND ROUTE 12.

0812 AM TSTM WND DMG CHICAGO 41.88N 87.63W
07/11/2011 COOK IL PUBLIC

LARGE TREE APPROXIMATELY 18 INCHES IN DIAMETER DOWN AT
THE INTERSECTION OF GOETHE ST AND LASALLE ST.

0812 AM TSTM WND GST 3 SW MIDWAY AIRPORT 41.75N 87.79W
07/11/2011 M75.00 MPH COOK IL CO-OP OBSERVER

0812 AM TSTM WND DMG MIDWAY AIRPORT 41.78N 87.75W
07/11/2011 COOK IL BROADCAST MEDIA

LARGE TREES DOWN NEAR AIRPORT. RELAYED BY FOX CHICAGO.

0812 AM TSTM WND DMG LINCOLN PARK 41.93N 87.64W
07/11/2011 COOK IL PUBLIC

12 INCH DIAMETER TREE LIMB DOWN AT THE INTERSECTION OF
DAYTON AND WILLOW.

0813 AM TSTM WND DMG GURNEE 42.38N 87.94W
07/11/2011 LAKE IL TRAINED SPOTTER

LARGE BRANCHES OFF TREES. WIND ESTIMATES OF NEAR 60 MPH.

0813 AM TSTM WND DMG ROUND LAKE 42.35N 88.11W
07/11/2011 LAKE IL TRAINED SPOTTER

8 INCH DIAMETER TREE SNAPPED OFF AT THE INTERSECTION OF
ROUTE 60 AND PETERSON RD.

0814 AM TSTM WND DMG 3 N PALOS HEIGHTS 41.71N 87.80W
07/11/2011 COOK IL EMERGENCY MNGR

*** 6 INJ *** A FESTIVAL TENT AT 109TH STREET AND 88TH
AVENUE NEAR MORAINE VALLEY COMMUNITY COLLEGE WAS LIFTED

AND THEN DROPPED ONTO SIX WORKERS CAUSING MINOR INJURIES.

0814 AM TSTM WND GST MIDWAY AIRPORT 41.78N 87.75W
07/11/2011 M75.00 MPH COOK IL ASOS

0815 AM TSTM WND DMG MIDWAY AIRPORT 41.78N 87.75W
07/11/2011 COOK IL PUBLIC

SEMI OVERTURNED ON 65TH AND MENARD. FENCES BLOWN DOWN
ALONG WITH 10 INCH DIAMETER BRANCHES. SHEET METAL AND
SHINGLES TORN OFF ROOFS.

0815 AM TSTM WND DMG MUNDELEIN 42.27N 88.00W
07/11/2011 LAKE IL TRAINED SPOTTER

MULTIPLE TREE LIMBS 3 TO 4 INCHES IN DIAMETER DOWN.

0815 AM TSTM WND DMG ARLINGTON HEIGHTS 42.09N 87.98W
07/11/2011 COOK IL PUBLIC

12 INCH DIAMETER TREE DOWN.

0815 AM TSTM WND DMG PALATINE 42.11N 88.04W
07/11/2011 COOK IL TRAINED SPOTTER

UP TO 8 INCH TREE BRANCHES DOWN.

0815 AM TSTM WND DMG BURBANK 41.74N 87.77W
07/11/2011 COOK IL TRAINED SPOTTER

POWER POLES DOWN ON HOMES.

0815 AM TSTM WND GST HOMETOWN 41.73N 87.73W
07/11/2011 E65.00 MPH COOK IL PUBLIC

0815 AM TSTM WND DMG BURBANK 41.74N 87.77W
07/11/2011 COOK IL TRAINED SPOTTER

TREES AND POWER LINES DOWN.

0816 AM TSTM WND GST WESTMONT 41.80N 87.97W
07/11/2011 E60.00 MPH DUPAGE IL PUBLIC

4 INCH DIAMETER TREES DOWN.

0817 AM TSTM WND DMG DARIEN 41.75N 87.98W
07/11/2011 DUPAGE IL TRAINED SPOTTER

12 TO 15 INCH DIAMETER TREE DOWN.

0817 AM TSTM WND DMG TINLEY PARK 41.57N 87.80W
07/11/2011 COOK IL TRAINED SPOTTER

DELAYED REPORT. TIME APPROXIMATE. 6 INCH DIAMETER LIMB
DOWN WITH SEVERAL SMALLER LIMBS DOWN THROUGHOUT THE
NEIGHBORHOOD. NEAR 169TH ST AND MARYLAND DR.

0818 AM TSTM WND GST ARLINGTON HEIGHTS 42.09N 87.98W
07/11/2011 E60.00 MPH COOK IL TRAINED SPOTTER

0819 AM TSTM WND GST EVERGREEN PARK 41.72N 87.70W
07/11/2011 M72.00 MPH COOK IL TRAINED SPOTTER

0820 AM TSTM WND DMG INVERNESS 42.12N 88.10W
07/11/2011 COOK IL TRAINED SPOTTER

POWER OUTAGES TO TRAFFIC SIGNALS.

0820 AM MARINE TSTM WIND 4 NE CHICAGO 41.92N 87.57W
07/11/2011 M73.00 MPH LMZ741 IL C-MAN STATION

63 KNOT GUST MEASURED AT CHICAGO CRIB. ANEMOMETER IS
LOCATED 85 FEET ABOVE LAKE SURFACE. DELAYED REPORT.

0821 AM TSTM WND DMG EVERGREEN PARK 41.72N 87.70W
07/11/2011 COOK IL PUBLIC

AT THE INTERSECTION OF 88TH AND UTICA...THERE IS A 12
INCH DIAMETER TREE DOWN THAT SNAPPED OFF AT THE BASE.

0822 AM TSTM WND DMG GREEN OAKS 42.30N 87.92W
07/11/2011 LAKE IL TRAINED SPOTTER

SEMI TRUCK BLOWN OVER ON I94 AT RT 176.

0824 AM MARINE TSTM WIND 4 E CHATHAM 41.73N 87.54W
07/11/2011 M46.00 MPH COOK IL C-MAN STATION

MEASURED AT CALUMET HARBOR STATION.

0827 AM TSTM WND GST LYONS 41.81N 87.82W
07/11/2011 E60.00 MPH COOK IL PUBLIC

SOME TREE DAMAGE.

0828 AM TSTM WND GST CHICAGO 41.88N 87.63W
07/11/2011 E60.00 MPH COOK IL TRAINED SPOTTER

6 INCH TREE LIMB DOWNED.

0830 AM TSTM WND DMG EVANSTON 42.05N 87.69W
07/11/2011 COOK IL PUBLIC

LARGE TREE LIMBS DOWN IN THE STREETS.

0830 AM MARINE TSTM WIND 4 NE CHICAGO 41.92N 87.57W
07/11/2011 M46.00 MPH LMZ741 IL C-MAN STATION

40 KNOT GUST AT CHICAGO CRIB.

0832 AM TSTM WND GST CHICAGO 41.88N 87.63W
07/11/2011 E55.00 MPH COOK IL TRAINED SPOTTER

0835 AM TSTM WND DMG CHICAGO 41.88N 87.63W
07/11/2011 COOK IL TRAINED SPOTTER

3 INCH TREE LIMBS DOWN AT INTERSECTION OF W LELAND AVE
AND NORTH WINCHESTER AVE.

0835 AM TSTM WND GST 2 SW SCHERERVILLE 41.47N 87.48W
07/11/2011 E50.00 MPH LAKE IN TRAINED SPOTTER

3 TO 4 INCH LIMBS DOWN.

1100 AM SEICHE 4 E CHATHAM 41.73N 87.54W
07/11/2011 COOK IL C-MAN STATION

BEGINNING AROUND 1100 AM CDT...WATER LEVELS MEASURED AT
CALUMET HARBOR STATION BEGAN FLUCTUATING BY 1 FT OR MORE
AND CONTINUED TO FLUCTUATE OVER A PERIOD OF ABOUT 3
HOURS.

1200 PM SEICHE 2 NNE CHICAGO 41.91N 87.62W
07/11/2011 LMZ741 IL PUBLIC

LIFEGUARDS AT NORTH AVENUE BEACH REPORTED RISING AND
FALLING LAKE LEVELS ASSOCIATED WITH A SEICHE.


&&

$$

RS

 


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