Alert archive / Illinois / Tornado Watches in 2006

Tornado Watch 791

September 22, 200639 counties in Illinois; Clinton County, Jackson County, Scott County, Iowa

The Storm Prediction Center issued this tornado watch at Sep 22, 2006, 3:32 PM CDT for 39 counties in Illinois; Clinton County, Jackson County, Scott County, Iowa. It took effect at Sep 22, 2006, 3:39 PM CDT. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Sep 22, 2006, 3:32 PM CDT (20:32 UTC)
In effect from
Sep 22, 2006, 3:39 PM CDT
Expired
Sep 22, 2006, 9:21 PM CDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
1.5 in
Strongest gust expected
60 kt
All 42 counties

Clinton County, IA, Jackson County, IA, Scott County, IA, Boone County, IL, Bureau County, IL, Carroll County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Ford County, IL, Fulton County, IL, Grundy County, IL, Hancock County, IL, Henderson County, IL, Henry County, IL, Iroquois County, IL, Jo Daviess 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, Marshall County, IL, McDonough County, IL, McHenry County, IL, McLean County, IL, Mercer County, IL, Ogle County, IL, Peoria County, IL, Putnam County, IL, Rock Island County, IL, Stark County, IL, Stephenson County, IL, Tazewell County, IL, Warren County, IL, Whiteside County, IL, Will County, IL, Winnebago County, IL, Woodford County, IL

The radar

The Quad Cities radar (KDVN), 95 km from the middle of the area, began a volume at 20:34 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
50%
One or more EF2 to EF5 tornadoes
30%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
30%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
10%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Sep 22, 3:34 PM CDTSevere Thunderstorm WarningDVNBureau, Whiteside56 min
Sep 22, 4:02 PM CDTSevere Thunderstorm WarningLOTLee, Ogle58 min
Sep 22, 4:06 PM CDTTornado WarningLOTDeKalb, Kane, LaSalle39 min
Sep 22, 4:14 PM CDTSevere Thunderstorm WarningILXCass, Fulton, Mason, Schuyler46 min
Sep 22, 4:25 PM CDTTornado WarningLOTCook, DuPage, Kane65 min
Sep 22, 4:26 PM CDTTornado WarningLOTLee42 min
Sep 22, 4:29 PM CDTSevere Thunderstorm WarningDVNWhiteside15 min
Sep 22, 4:43 PM CDTSevere Thunderstorm WarningILXFulton, Mason, Tazewell47 min
Sep 22, 4:55 PM CDTSevere Thunderstorm WarningLOTDeKalb35 min
Sep 22, 5:00 PM CDTSevere Thunderstorm WarningILXWoodford35 min
Sep 22, 5:04 PM CDTSevere Thunderstorm WarningLOTKane26 min
Sep 22, 5:11 PM CDTTornado WarningLOTDeKalb19 min
Sep 22, 5:16 PM CDTSevere Thunderstorm WarningLOTGrundy, Kendall, LaSalle, Will44 min
Sep 22, 5:18 PM CDTTornado WarningLOTKane42 min
Sep 22, 5:22 PM CDTSevere Thunderstorm WarningLOTCook, DuPage53 min
Sep 22, 5:52 PM CDTTornado WarningLOTCook24 min
Sep 22, 6:04 PM CDTFlash Flood WarningLOTCook, DuPage3 hr
Sep 22, 6:10 PM CDTTornado WarningLOTCook23 min
Sep 22, 6:38 PM CDTSevere Thunderstorm WarningILXMcLean52 min
Sep 22, 8:04 PM CDTSevere Thunderstorm WarningLOTIroquois30 min

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 12:00Z, 8.5 hours before the alert went out and 88 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 12:00Z on 2006-09-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 12:00Z on 2006-09-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 439 square meters per square second.19395878Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
840 m above ground
0-6 km bulk shear
49 kt
0-1 km storm-relative helicity
439 m²/s²
0-3 km storm-relative helicity
440 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 22, 12:49 PM CDTMesoscale DiscussionSPCAdams, Alexander, Bond, Brown, Calhoun, Cass and 38 more2 hr
Sep 22, 1:16 PM CDTTornado WatchSPCAdams, Alexander, Bond, Brown, Calhoun, Cass and 42 more8 hr
Sep 22, 2:20 PM CDTMesoscale DiscussionSPCBoone, Bureau, Carroll, Cook, DeKalb, DuPage and 30 more2 hr
Sep 22, 2:55 PM CDTMesoscale DiscussionSPCGallatin, Hamilton, Hardin, Johnson, Massac, Pope and 2 more2 hr
Sep 22, 3:00 PM CDTMesoscale DiscussionSPCAdams, Alexander, Bond, Brown, Calhoun, Cass and 45 more90 min
Sep 22, 3:37 PM CDTTornado WatchSPCEdwards, Gallatin, Hamilton, Hardin, Massac, Pope and 4 more8 hr
Sep 22, 5:08 PM CDTMesoscale DiscussionSPCAlexander, Bond, Brown, Calhoun, Cass, Christian and 44 more2 hr
Sep 22, 5:37 PM CDTMesoscale DiscussionSPCBoone, Bureau, Cook, DeKalb, DuPage, Ford and 24 more113 min

Nearby

Tornado Watches in Illinois, 2006Tornado Watches in Iowa, 2006Every tornado watch in 2006

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.