Alert archive / Illinois / Severe Thunderstorm Warnings in 2008

Severe Thunderstorm Warning 142, NWS Chicago, IL

July 12, 2008LaSalle County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at Jul 12, 2008, 3:31 AM CDT for LaSalle County, Illinois. It was in force for 44 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Jul 12, 2008, 3:31 AM CDT (08:31 UTC)
Expired
Jul 12, 2008, 4:15 AM CDT
In force
44 min
Issued by
NWS Chicago, IL
Area
Storm-based polygon

County LaSalle County, IL

The radar

The Chicago radar (KLOT), 73 km from the middle of the area, began a volume at 08:33 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.

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 8.5 hours before the alert went out and 135 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, Lincoln, IL at 00:00Z on 2008-07-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 389 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, Lincoln, IL at 00:00Z on 2008-07-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 97 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
389 J/kg
Mixed-layer CIN
-185 J/kg
Mixed-layer LCL
1379 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
97 m²/s²
0-3 km storm-relative helicity
175 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.0

Open this sounding in Storm Lab

The office that day

Everything else NWS Chicago, IL issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 12, 3:36 AM CDTAreal Flood AdvisoryLOTBoone, DeKalb, Kane, Lee, McHenry, Ogle and 1 more6 hr
Jul 12, 3:46 AM CDTSpecial Marine WarningLOT119 min
Jul 12, 4:15 AM CDTSevere Thunderstorm WarningLOTGrundy, Kendall, LaSalle60 min
Jul 12, 4:39 AM CDTSevere Thunderstorm WarningLOTCook, DeKalb, DuPage, Kane, Kendall, LaSalle and 2 more66 min
Jul 12, 5:05 AM CDTSevere Thunderstorm WarningLOTGrundy, Kendall, LaSalle, Livingston55 min
Jul 12, 5:33 AM CDTSpecial Marine WarningLOT87 min
Jul 12, 5:44 AM CDTAreal Flood AdvisoryLOTGrundy, LaSalle, Livingston6 hr
Jul 12, 9:36 AM CDTRiver Flood WarningLOTOgle3 days

Nearby

Severe Thunderstorm Warnings in Illinois, 2008Every severe thunderstorm warning 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.