Alert archive / Illinois / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 2, NWS Chicago, IL

April 5, 1997Ogle County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at Apr 5, 1997, 3:45 PM CST for Ogle County, Illinois. It was in force for 45 min. 1 report came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Apr 5, 1997, 3:45 PM CST (21:45 UTC)
Expired
Apr 5, 1997, 4:30 PM CST
In force
45 min
Issued by
NWS Chicago, IL
Area
Whole counties

County Ogle County, IL

The radar

The Chicago radar (KLOT), 113 km from the middle of the area, began a volume at 21:44 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 was reported inside it

TimeReportWhereRemark
Apr 5, 3:50 PM CSTThunderstorm Wind 50Polo, IL

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 9.8 hours before the alert went out and 108 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 1997-04-05Temperature 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 1997-04-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 94 square meters per square second.1939587897Sfc1 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
515 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
94 m²/s²
0-3 km storm-relative helicity
99 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 052147 RRA
SVRCHI
ILC141-099-105-103-052230-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE CHICAGO IL
345 PM CST SAT APR 5 1997
 
THE NATIONAL WEATHER SERVICE IN CHICAGO HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  430 PM CST
FOR PEOPLE IN THE FOLLOWING LOCATIONS...
 
IN NORTH CENTRAL ILLINOIS
 
   ...LEE COUNTY...OGLE COUNTY
 
IN NORTHEAST ILLINOIS
 
   ...LA SALLE COUNTY...LIVINGSTON COUNTY
 
AT 350 PM CST RADAR INDICATED A LINE OF SEVERE THUNDFERSTORMS EXTENDING
FROM NEAR STERLING IN EASTERN WHITESIDE COUNTY...TO JUST NORTHEAST OF
BLOOMINGTON. THIS LINE IS MOVING RAPIDLY NORTHEAST AT 50 MPH AND WILL BE
AFFECTING OREGON...DIXON...AMBOY...LA SALLE...OTTAWA...AND PONTIAC BY
430 PM CST.
 
THIS STORM HAS A HISTORY OF PRODUCING DAMAGING WIND GUSTS OF 60 TO 70
MPH. 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, 11:16 AM CST, 4 hours 29 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
NATIONAL WEATHER SERVICE CHICAGO IL
1108 AM CST (1208 PM EST) SAT APR 5 1997

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

THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS THE AREA THIS AFTERNOON
AND CONTINUE INTO THIS EVENING. HOWEVER THE THUNDERSTORMS ARE NOT
EXPECTED TO BECOME SEVERE.

A WEAK COLD FRONT IS EXPECTED TO SWEEP THROUGH THE AREA THIS EVENING
BRINGING THE THREAT OF THUNDERSTORMS TO THE AREA. CONSIDERABLE
CLOUDINESS AHEAD OF THE FRONT SHOULD INHIBIT HEATING THIS AFTERNOON SO
THE THUNDERSTORMS SHOULD REMAIN BELOW THE SEVERE CATERGORY IN SPITE OF
ABUNDANT GULF MOISTURE AND A VIGOROUS UPPER LEVEL DISTURBANCE MOVING
THROUGH THE AREA.

ALM
Special weather statement, Apr 5, 2:10 PM CST, 1 hour 35 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.

IssuedProductOfficeCountiesLasted
Apr 5, 3:45 PM CSTSevere Thunderstorm WarningLOTLaSalle, Lee, Livingston45 min
Apr 5, 4:26 PM CSTSevere Thunderstorm WarningLOTDeKalb, Grundy, Kendall, LaSalle34 min
Apr 5, 4:26 PM CSTSevere Thunderstorm WarningLOTFord, Livingston34 min
Apr 5, 4:26 PM CSTSevere Thunderstorm WarningLOTLee34 min
Apr 5, 4:59 PM CSTSevere Thunderstorm WarningLOTFord, Iroquois, Kankakee31 min
Apr 5, 4:59 PM CSTSevere Thunderstorm WarningLOTBoone, DeKalb, Kane, Kendall, McHenry31 min
Apr 5, 4:59 PM CSTSevere Thunderstorm WarningLOTGrundy, Will31 min
Apr 5, 4:59 PM CSTSevere Thunderstorm WarningLOTDuPage31 min
Apr 5, 5:26 PM CSTSevere Thunderstorm WarningLOTCook, Lake, McHenry34 min
Apr 5, 5:26 PM CSTSevere Thunderstorm WarningLOTDuPage, Kankakee, Will34 min
Apr 5, 5:26 PM CSTSevere Thunderstorm WarningLOTIroquois34 min

Nearby

Severe Thunderstorm Warnings in Illinois, 1997Every 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.