Alert archive / Illinois / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 13, NWS Chicago, IL

April 5, 1997Iroquois County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at Apr 5, 1997, 5:26 PM CST for Iroquois County, Illinois. It was in force for 34 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: Apr 5, 1997, 5:26 PM CST (23:26 UTC)
Expired: Apr 5, 1997, 6:00 PM CST
In force: 34 min
Issued by: NWS Chicago, IL
Area: Whole counties

County Iroquois County, IL

The radar

The Chicago radar (KLOT), 98 km from the middle of the area, began a volume at 23:29 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Apr 5, 2:30 PM CST	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 11.4 hours before the alert went out and 93 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 502 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: 132 m²/s²
0-3 km storm-relative helicity: 118 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
TTAA00 KCHI 052327 RRA
SVRCHI
ILC075-031-043-091-097-111-197-ILZ520-521-522-523-060000-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM AND SPECIAL MARINE WARNING
NATIONAL WEATHER SERVICE CHICAGO IL
526 PM CST SAT APR 5 1997
 
THE NATIONAL WEATHER SERVICE IN CHICAGO HAS ISSUED A
SEVERE THUNDERSTORM AND SPECIAL MARINE WARNING
EFFECTIVE UNTIL  600 PM CST
FOR PEOPLE IN THE FOLLOWING LOCATIONS...
 
IN EAST CENTRAL ILLINOIS
 
   ...IROQUOIS COUNTY
IN NORTHEAST ILLINOIS
 
   ...COOK COUNTY...DU PAGE COUNTY...EASTERN KANKAKEE COUNTY
   ...LAKE COUNTY...EASTERN MCHENRY COUNTY...WILL COUNTY
 
  AND FOR MARINE INTERESTS ON SOUTHERN LAKE MICHIGAN FROM
 
   ... WINTHROP HARBOR  TO   CALUMET HARBOR
 
AT 530 PM CST A LINE OF SEVERE THUNDERSTORMS EXTENDED FROM
WOODSTOCK...TO ELGIN...TO WEST JOLIET...TO JUST WEST OF KANKAKEEAND
ABOUT 10 MILES WEST OF WATSEKA.
 
THE LINE IS MOVING EAST NORTHEAST AT 50 MPH AND WILL REACH LAKE MICHIGAN
BY 6 PM CST.
 
THIS STORM HAS A HISTORY OF PRODUCING DAMAGING WINDS.  GO INSIDE
A STURDY BUILDING AND STAY AWAY FROM WINDOWS!
 
 
MERZLOCK

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

In the hours before

Special weather statement, Apr 5, 2:10 PM CST, 3 hours 16 minutes before

ILZ003>006-008-010>014-019>023-032-033-039-520>523-INZ001>005-
010>016-019-020-520>522-LMZ530-061000-

HAZARDOUS WEATHER OUTLOOK/UPDATED
NATIONAL WEATHER SERVICE CHICAGO IL
2 10 PM CST (1208 PM EST) SAT APR 5 1997

FOR NORTH CENTRAL AND NORTHEAST ILLINOIS AND NORTHWEST AND NORTH
CENTRAL INDIANA

...SEVERE THUNDERSTORMS ARE POSSIBLE ACROSS THE AREA THIS EVENING...

A WEAK COLD FRONT IS EXPECTED TO SWEEP THROUGH THE AREA THIS EVENING
BRINGING THE THREAT OF SEVERE THUNDERSTORMS TO THE AREA.

AT 2 PM CST THIS AFTERNOON A LINE OF SEVERE THUNDERSTORMS HAD DEVELOPED
IN EXTREME WEST CENTRAL ILLINOIS NEAR THE MISSISSIPPI RIVER AND EXTENDED
SOUTHWARD TO NEAR ST LOUIS. THIS BAND OF THUNDERSTORMS WERE MOVING
NORTHEAST AROUND 40 MPH AND SHOULD MOVE INTO NORTHEAST AND
NORTH CENTAL ILLINOIS EARLY THIS EVENING THEN INTO NORTHWEST AND
NORTH CENTRAL INDIANA LATER THIS EVENING.

ALM

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 5, 3:45 PM CST	Severe Thunderstorm Warning	LOT	LaSalle, Lee, Livingston	45 min
Apr 5, 3:45 PM CST	Severe Thunderstorm Warning	LOT	Ogle	45 min
Apr 5, 4:26 PM CST	Severe Thunderstorm Warning	LOT	DeKalb, Grundy, Kendall, LaSalle	34 min
Apr 5, 4:26 PM CST	Severe Thunderstorm Warning	LOT	Ford, Livingston	34 min
Apr 5, 4:26 PM CST	Severe Thunderstorm Warning	LOT	Lee	34 min
Apr 5, 4:59 PM CST	Severe Thunderstorm Warning	LOT	Ford, Iroquois, Kankakee	31 min
Apr 5, 4:59 PM CST	Severe Thunderstorm Warning	LOT	Boone, DeKalb, Kane, Kendall, McHenry	31 min
Apr 5, 4:59 PM CST	Severe Thunderstorm Warning	LOT	Grundy, Will	31 min
Apr 5, 4:59 PM CST	Severe Thunderstorm Warning	LOT	DuPage	31 min
Apr 5, 5:26 PM CST	Severe Thunderstorm Warning	LOT	Cook, Lake, McHenry	34 min
Apr 5, 5:26 PM CST	Severe Thunderstorm Warning	LOT	DuPage, Kankakee, Will	34 min

Nearby

Severe Thunderstorm Warnings in Illinois, 1997 Every severe thunderstorm warning 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; radar from the NEXRAD Level II archive.