Alert archive / Illinois / Severe Thunderstorm Watches in 1997

Severe Thunderstorm Watch 497

June 21, 19974 states

The Storm Prediction Center issued this severe thunderstorm watch at Jun 21, 1997, 7:00 AM CDT for 4 states. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Jun 21, 1997, 7:00 AM CDT (12:00 UTC)
Expired
Jun 21, 1997, 11:00 AM CDT
In force
4 hr
Issued by
the Storm Prediction Center
All 41 counties

Boone County, IL, Bureau 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, Stephenson County, IL, Will County, IL, Winnebago County, IL, Woodford County, IL, Benton County, IN, Carroll County, IN, Jasper County, IN, Lake County, IN, LaPorte County, IN, Newton County, IN, Porter County, IN, Pulaski County, IN, Starke County, IN, White County, IN, Berrien County, MI, Green County, WI, Kenosha County, WI, Milwaukee County, WI, Racine County, WI, Rock County, WI, Walworth County, WI

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Jun 21, 7:32 AM CDTSevere Thunderstorm WarningMKXRock, Walworth63 min
Jun 21, 7:40 AM CDTFlash Flood WarningMKXMilwaukee, Waukesha2 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 0.0 hours before the alert went out and 207 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 12:00Z on 1997-06-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3170 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 12:00Z on 1997-06-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 187 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
3170 J/kg
Mixed-layer CIN
-37 J/kg
Mixed-layer LCL
624 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
187 m²/s²
0-3 km storm-relative helicity
146 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 21, 1:30 AM CDTSevere Thunderstorm WatchSPCMercer6 hr
Jun 21, 2:15 AM CDTSevere Thunderstorm WatchSPCBoone, Carroll, Cook, DeKalb, DuPage, Jo Daviess and 9 more5 hr
Jun 21, 5:15 PM CDTSevere Thunderstorm WatchSPCAdams, Allen, Blackford, Boone, Carroll, Cass and 32 more5 hr
Jun 21, 3:00 PM CDTTornado WatchSPCBarry, Bay, Branch, Calhoun, Cass, Clinton and 20 more5 hr

Nearby

Severe Thunderstorm Watches in Illinois, 1997Severe Thunderstorm Watches in Indiana, 1997Severe Thunderstorm Watches in Wisconsin, 1997Every severe thunderstorm watch in 1997

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.