Alert archive / Illinois / Tornado Watches in 2008

Tornado Watch 494

June 8, 200834 counties in Illinois; Lake County, Indiana; Kenosha County, Racine County, Walworth County, Wisconsin

The Storm Prediction Center issued this tornado watch at Jun 8, 2008, 8:03 PM CDT for 34 counties in Illinois; Lake County, Indiana; Kenosha County, Racine County, Walworth County, Wisconsin. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Jun 8, 2008, 8:03 PM CDT (01:03 UTC)
Expired
Jun 9, 2008, 12:53 AM CDT
In force
5 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
70 kt
All 38 counties

Boone County, IL, Bureau County, IL, Cass County, IL, Cook County, IL, DeKalb County, IL, DeWitt County, IL, DuPage County, IL, Ford County, IL, Fulton County, IL, Grundy County, IL, Iroquois County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, Knox County, IL, Lake County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Logan County, IL, Marshall County, IL, Mason County, IL, McHenry County, IL, McLean County, IL, Menard County, IL, Ogle County, IL, Peoria County, IL, Putnam County, IL, Schuyler County, IL, Stark County, IL, Tazewell County, IL, Will County, IL, Winnebago County, IL, Woodford County, IL, Lake County, IN, Kenosha County, WI, Racine County, WI, Walworth County, WI

The radar

The Chicago radar (KLOT), 41 km from the middle of the area, began a volume at 01:04 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
40%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
80%
One or more gusts of 65 knots or more
60%
Ten or more severe hail reports
40%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
90%

Warnings issued inside it

13 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Jun 8, 8:36 PM CDTSevere Thunderstorm WarningLOTBoone, Lake, McHenry, Winnebago54 min
Jun 8, 8:38 PM CDTSevere Thunderstorm WarningMKXKenosha, Racine, Walworth76 min
Jun 8, 8:42 PM CDTFlash Flood WarningMKXKenosha, Racine, Walworth2 hr
Jun 8, 8:55 PM CDTTornado WarningMKXKenosha, Walworth35 min
Jun 8, 9:00 PM CDTSevere Thunderstorm WarningILXKnox, Peoria, Stark45 min
Jun 8, 9:00 PM CDTSevere Thunderstorm WarningLOTBoone, DeKalb, Kane, Lake, McHenry, Ogle and 1 more48 min
Jun 8, 9:04 PM CDTSevere Thunderstorm WarningDVNBureau, Carroll, Henry, Mercer, Rock Island, Stephenson and 1 more56 min
Jun 8, 9:41 PM CDTSevere Thunderstorm WarningLOTCook, DuPage, Kane, Lake, McHenry64 min
Jun 8, 9:44 PM CDTSevere Thunderstorm WarningILXKnox, Marshall, Peoria, Stark46 min
Jun 8, 10:02 PM CDTSevere Thunderstorm WarningLOTLee28 min
Jun 8, 10:31 PM CDTSevere Thunderstorm WarningLOTLee29 min
Jun 8, 10:58 PM CDTSevere Thunderstorm WarningLOTLaSalle17 min
Jun 8, 11:14 PM CDTFlash Flood WarningLOTWinnebago3 hr

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 1.1 hours before the alert went out and 171 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Davenport, at 00:00Z on 2008-06-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2433 joules per kilogram.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Davenport, at 00:00Z on 2008-06-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 157 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
2433 J/kg
Mixed-layer CIN
-9 J/kg
Mixed-layer LCL
1200 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
157 m²/s²
0-3 km storm-relative helicity
166 m²/s²
Significant tornado parameter
1.4
Supercell composite
10.9

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 8, 7:52 PM CDTMesoscale DiscussionSPCBoone, Bureau, Cass, DeKalb, DeWitt, DuPage and 20 more53 min
Jun 8, 10:01 PM CDTMesoscale DiscussionSPCAdams, Boone, Brown, Bureau, Carroll, Cass and 40 more59 min
Jun 9, 12:18 PM CDTMesoscale DiscussionSPCClark, Clay, Crawford, Cumberland, Edgar, Edwards and 14 more87 min
Jun 9, 12:38 PM CDTSevere Thunderstorm WatchSPCClark, Clay, Crawford, Cumberland, Edgar, Effingham and 3 more8 hr
Jun 9, 3:02 PM CDTMesoscale DiscussionSPCClark, Clay, Crawford, Cumberland, Edgar, Effingham and 4 more118 min
Jun 9, 4:49 PM CDTSevere Thunderstorm WatchSPCAlexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 12 more6 hr
Jun 9, 12:42 PM CDTSevere Thunderstorm WatchSPCFayette, Franklin, Union, Wayne9 min
Jun 9, 6:04 PM CDTMesoscale DiscussionSPCDeKalb56 min

Nearby

Tornado Watches in Illinois, 2008Tornado Watches in Wisconsin, 2008Tornado Watches in Indiana, 2008Every tornado watch in 2008

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.