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A warm front stretching west to east across northern Illinois and Indiana provided the focus for severe convection and flooding Wednesday afternoon and evening. Dewpoints in the lower 70s south of the boundary provided moisture to fuel these storms. As these storms initiated during the late afternoon, strong vertical wind shear quickly turned many of them into supercells capable of producing large hail and tornadoes.
Surface moisture convergence graphic from SPC (with front and low position added) valid 10 PM CDT during the height of the event.
A tornado watch was issued by the Storm Prediction Center at 7:00 PM CDT for parts of eastern Iowa, a large part of northern Illinois, and parts of northern Indiana. This was the easternmost of three tornado watches stretching into eastern Colorado that evening.
Watch status as of 11:57 PM CDT on June 4, 2008.
At 7:11 PM CDT the NWS office in Chicago issued the first of 10 tornado warnings for the evening. Interestingly, the first few tornadic circulations were very intense, yet anticyclonic. Unlike the great majority of tornadic circulations, and thunderstorm circulations in general, these first few storms were rotating clockwise, as seen in the following radar images.
Doppler radar storm-relative motion image from 7:33 PM CDT June 4.
Red values in the image show winds moving away from the radar, or toward the southeast. Green values show winds moving toward the radar, or toward the northwest. This particular image shows winds of 50-60 knots blowing in opposite directions but very close together. This is an excellent indication that a storm may be producing a tornado, though normally the circulation is cyclonic, meaning counter-clockwise.
In the next graphic is the reflectivity image for the same storm.
Super-resolution reflectivity image from 07:33 PM CDT on June 4, 2008.
The image above depicts a very strong and somewhat unusual left-moving supercell. The rotation in this storm, in what could be described as a hook echo, is located on the northern side of the cell. The storm itself is moving to the northeast.
Shortly after these left-mover, or anticyclonic, supercells developed, traditional cyclonic supercells also began to form in the area. The reflectivity and velocity patterns in these are more familiar.
Super-resolution reflectivity image from 8:00 PM CDT on June 4, 2008.
The hook feature shown above is on the southern side of the storm, which is moving almost due east.
Doppler radar storm-relative motion image for 8:00 PM on June 4, 2008.
In this image the cyclonic, or counterclockwise rotation is shown. It does not appear to be as wide and as strong as the image shown earlier, but there still were multiple tornado reports with this storm in southwest Livingston County, Illinois.
NWUS53 KLOT 051742 LSRLOT PRELIMINARY LOCAL STORM REPORT...SUMMARY NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 1242 PM CDT THU JUN 05 2008 ..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON... ..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE.... ..REMARKS.. 0710 PM HAIL 2 NNW REMINGTON 40.79N 87.17W 06/04/2008 E1.00 INCH JASPER IN TRAINED SPOTTER 0713 PM FUNNEL CLOUD REMINGTON 40.76N 87.15W 06/04/2008 JASPER IN TRAINED SPOTTER MULTIPLE REPORTS OF ROTATION NEAR US HWY 24 AND I-65. 0720 PM HAIL 5 W WATSEKA 40.78N 87.83W 06/04/2008 M0.88 INCH IROQUOIS IL CO-OP OBSERVER 0730 PM TORNADO 3 E RENSSELAER 40.94N 87.09W 06/04/2008 JASPER IN LAW ENFORCEMENT SMALL TORNADO ON THE GROUND. 0746 PM FUNNEL CLOUD 2 S RAUB 40.70N 87.49W 06/04/2008 BENTON IN EMERGENCY MNGR 0801 PM TORNADO 7 S FLANAGAN 40.77N 88.87W 06/04/2008 LIVINGSTON IL PUBLIC TRUCKER REPORTS TWO TORNADOES MERGING WEST OF I-55 NEAR MILE MARKER 190. 0803 PM TORNADO 7 S FLANAGAN 40.78N 88.86W 06/04/2008 LIVINGSTON IL TRAINED SPOTTER TORNADO ON THE GROUND AT INTERSECTION OF 200E AND 1100N. 0804 PM TORNADO 7 S FLANAGAN 40.78N 88.86W 06/04/2008 LIVINGSTON IL LAW ENFORCEMENT OUTBUILDINGS DESTROYED. LOCATION IS 3-4 MILES NORTH OF GRIDLEY. 0810 PM HAIL ASHKUM 40.88N 87.95W 06/04/2008 E1.75 INCH IROQUOIS IL EMERGENCY MNGR 0823 PM TORNADO 3 S PONTIAC 40.83N 88.64W 06/04/2008 LIVINGSTON IL LAW ENFORCEMENT 0836 PM HAIL MOUNT AYR 40.95N 87.30W 06/04/2008 E1.00 INCH NEWTON IN EMERGENCY MNGR 0950 PM HAIL CHICAGO HEIGHTS 41.51N 87.64W 06/04/2008 M1.00 INCH COOK IL LAW ENFORCEMENT 0955 PM HAIL SAUK VILLAGE 41.49N 87.57W 06/04/2008 M1.75 INCH COOK IL LAW ENFORCEMENT 1006 PM HAIL GRIFFITH 41.52N 87.42W 06/04/2008 M0.88 INCH LAKE IN TRAINED SPOTTER 1010 PM FLASH FLOOD KANKAKEE 41.12N 87.86W 06/04/2008 KANKAKEE IL TRAINED SPOTTER SEVERAL STREETS FLOODED IN CITY WITH UP TO 4 TO 5 FEET OF WATER. MOTORIST RESCUED NEAR BROOKMONT BLVD. 1040 PM HAIL CRETE 41.45N 87.62W 06/04/2008 M0.75 INCH WILL IL TRAINED SPOTTER 1042 PM HAIL MANHATTAN 41.43N 87.99W 06/04/2008 M0.25 INCH WILL IL EMERGENCY MNGR AT GOUGAR RD. AND MANHATTAN RD. 1052 PM HEAVY RAIN BRADLEY 41.15N 87.86W 06/04/2008 M2.60 INCH KANKAKEE IL TRAINED SPOTTER MEASURED SINCE RAIN BEGAN AT 9 PM 1118 PM TSTM WND DMG 2 E FAIR OAKS 41.08N 87.22W 06/04/2008 JASPER IN LAW ENFORCEMENT TREE DOWN. 1127 PM FUNNEL CLOUD 3 S DE MOTTE 41.16N 87.20W 06/04/2008 JASPER IN LAW ENFORCEMENT 1153 PM HAIL ROMEOVILLE 41.65N 88.09W 06/04/2008 M0.75 INCH WILL IL TRAINED SPOTTER 1227 AM FLOOD KANKAKEE 41.12N 87.86W 06/05/2008 KANKAKEE IL LAW ENFORCEMENT NUMEROUS ROADS CLOSED ACROSS KANKAKEE COUNTY. 1233 AM FLOOD MANHATTAN 41.43N 87.99W 06/05/2008 WILL IL LAW ENFORCEMENT MULTIPLE ROADS IN EASTERN WILL COUNTY ARE CLOSED. 1257 AM FLOOD MOROCCO 40.95N 87.45W 06/05/2008 NEWTON IN LAW ENFORCEMENT HIGH WATER ACROSS MANY LOCATIONS IN THE COUNTY. 0100 AM FLOOD STEGER 41.47N 87.64W 06/05/2008 COOK IL LAW ENFORCEMENT MINOR ROADWAY FLOODING IN TOWN. NO ROADS CLOSED YET. 0206 AM HEAVY RAIN 2 S WHEATFIELD 41.16N 87.05W 06/05/2008 M4.48 INCH JASPER IN CO-OP OBSERVER 4.1 IN PAST 2.5 HOURS 0210 AM HAIL NORRIDGE 41.97N 87.82W 06/05/2008 E0.75 INCH COOK IL LAW ENFORCEMENT 0450 AM FLASH FLOOD 2 WNW MONEE 41.43N 87.79W 06/05/2008 WILL IL LAW ENFORCEMENT ROUTE 50 NEAR EAGLE CREEK IMPASSIBLE 0501 AM FLASH FLOOD KANKAKEE 41.12N 87.86W 06/05/2008 KANKAKEE IL LAW ENFORCEMENT ROADS CLOSED ACROSS THE COUNTY-KANKAKEE COUNTY SHERIFF 0520 AM FLASH FLOOD WHEATFIELD 41.19N 87.05W 06/05/2008 JASPER IN LAW ENFORCEMENT JASPER COUNTY SHERIFF REPORTS THAT THE HARDEST HIT AREA IS IN WHEATFIELD AND DE MOTTE. SOME CITY ROADS CLOSED. SOME HOUSES WITH WATER IN BASEMENT. 0525 AM FLASH FLOOD MOROCCO 40.95N 87.45W 06/05/2008 NEWTON IN LAW ENFORCEMENT ROADS CLOSED ACROSS THE COUNTY-NEWTON COUNTY SHERIFF 0605 AM FLASH FLOOD BOURBONNAIS 41.16N 87.88W 06/05/2008 KANKAKEE IL BROADCAST MEDIA 5.2 INCHES-STORM TOTAL. NEIGHBORS CORN FIELD FLOODED. CAN NOT GET OUT OF DRIVE WAY DUE TO FLOODING. RELAYED BY ABC 7 CHICAGO 0605 AM FLASH FLOOD LOWELL 41.29N 87.41W 06/05/2008 LAKE IN BROADCAST MEDIA 4.0 INCHES OF RAIN. RELAYED BY ABC 7 CHICAGO 0728 AM TSTM WND GST MOUNT MORRIS 42.05N 89.43W 06/05/2008 E70.00 MPH OGLE IL TRAINED SPOTTER 0730 AM TSTM WND DMG FORRESTON 42.13N 89.58W 06/05/2008 OGLE IL LAW ENFORCEMENT SEVERAL TREES DOWN THROUGHOUT COUNTY. RADAR TIME APPROX. 0745 AM TSTM WND GST ROCKFORD AIRPORT 42.20N 89.10W 06/05/2008 M64.00 MPH WINNEBAGO IL ASOS 0745 AM HEAVY RAIN POLO 41.98N 89.58W 06/05/2008 M0.94 INCH OGLE IL CO-OP OBSERVER MEASURED IN 10 MINUTES. ALSO PEA SIZED HAIL. 0800 AM TSTM WND DMG MARENGO 42.25N 88.60W 06/05/2008 MCHENRY IL LAW ENFORCEMENT TREE DOWN IN MARENGO. 0822 AM TSTM WND DMG CRYSTAL LAKE 42.23N 88.33W 06/05/2008 MCHENRY IL EMERGENCY MNGR DOWNED POWER LINES AND TREE LIMBS 0853 AM HEAVY RAIN 2 SE MCHENRY 42.32N 88.26W 06/05/2008 E1.00 INCH MCHENRY IL AIRPLANE PILOT 0920 AM TSTM WND DMG 3 W WINNEBAGO 42.27N 89.30W 06/05/2008 WINNEBAGO IL LAW ENFORCEMENT MANY TREES DOWN ACROSS THE COUNTY...ONE TREE BLOCKING WESTFIELD RD...ANOTHER TREE ON POWER LINE ON SILVER CREEK RD. 1206 PM FLOOD WHEATFIELD 41.19N 87.05W 06/05/2008 JASPER IN LAW ENFORCEMENT WASHED OUT COLVERT IN WHEATFIELD. COUNTY HIGHWAY OFFERING SANDBAGS TO ANYONE IN NEED. |