Alert archive / Illinois / Severe Thunderstorm Watches in 2002

Severe Thunderstorm Watch 146

April 24, 200223 counties in Illinois; 18 counties in Wisconsin

The Storm Prediction Center issued this severe thunderstorm watch at Apr 24, 2002, 1:30 PM CDT for 23 counties in Illinois; 18 counties in Wisconsin. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Apr 24, 2002, 1:30 PM CDT (18:30 UTC)
Expired
Apr 24, 2002, 7:00 PM CDT
In force
6 hr
Issued by
the Storm Prediction Center
All 41 counties

Boone County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Ford County, IL, Grundy County, IL, Iroquois County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, Lake County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Marshall County, IL, McHenry County, IL, McLean County, IL, Ogle County, IL, Putnam County, IL, Tazewell County, IL, Will County, IL, Winnebago County, IL, Woodford County, IL, Calumet County, WI, Dodge County, WI, Fond du Lac County, WI, Green Lake County, WI, Jefferson County, WI, Kenosha County, WI, Manitowoc County, WI, Milwaukee County, WI, Outagamie County, WI, Ozaukee County, WI, Racine County, WI, Rock County, WI, Sheboygan County, WI, Walworth County, WI, Washington County, WI, Waukesha County, WI, Waupaca County, WI, Winnebago County, WI

The radar

The Chicago radar (KLOT), 65 km from the middle of the area, began a volume at 18:30 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.

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 24, 3:13 PM CDTSevere Thunderstorm WarningILXLogan, Tazewell62 min

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 6.5 hours before the alert went out and 162 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 2002-04-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 28 joules per kilogram.LCLLFCEL10008507005003002001001 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 2002-04-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 99 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
28 J/kg
Mixed-layer CIN
-364 J/kg
Mixed-layer LCL
846 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
99 m²/s²
0-3 km storm-relative helicity
112 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
Apr 24, 10:15 AM CDTSevere Thunderstorm WatchSPCAdams, Bond, Brown, Calhoun, Cass, Christian and 30 more5 hr
Apr 24, 2:30 PM CDTTornado WatchSPCAdams, Alexander, Bond, Brown, Calhoun, Cass and 49 more6 hr
Apr 24, 3:30 PM CDTTornado WatchSPCGallatin, Hardin5 hr

Nearby

Severe Thunderstorm Watches in Illinois, 2002Severe Thunderstorm Watches in Wisconsin, 2002Every severe thunderstorm watch in 2002

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.