Alert archive / Illinois / Tornado Warnings in 1997

Tornado Warning 1, NWS Chicago, IL

April 30, 1997Lee County, Illinois

NWS Chicago, IL issued this tornado warning at Apr 30, 1997, 2:41 PM CDT for Lee 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 30, 1997, 2:41 PM CDT (19:41 UTC)
Expired
Apr 30, 1997, 3:15 PM CDT
In force
34 min
Issued by
NWS Chicago, IL
Area
Whole counties

County Lee County, IL

The radar

The Chicago radar (KLOT), 102 km from the middle of the area, began a volume at 19:40 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.

IssuedProductOfficeLasted
Apr 30, 12:30 PM CDTTornado WatchSPC7 hr

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 7.7 hours before the alert went out and 101 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 1997-04-30Temperature 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 1997-04-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 75 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1366 m above ground
0-6 km bulk shear
54 kt
0-1 km storm-relative helicity
75 m²/s²
0-3 km storm-relative helicity
180 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 301943 RRA
TORCHI
ILC103-302015-
 
BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE CHICAGO IL
241 PM CDT WED APR 30 1997
 
THE NATIONAL WEATHER SERVICE IN CHICAGO HAS ISSUED A
TORNADO WARNING EFFECTIVE UNTIL  315 PM CDT
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN NORTH CENTRAL ILLINOIS
 
   ...LEE COUNTY
 
AT 240 PM CDT RADAR INDICATED A SEVERE THUNDERSTORM AND POSSIBLE TORNADO
OVER EXTREME NORTHEAST BUREAU COUNTY...ABOUT 7 MILES E`AST OF WALNUT.
THIS STORM IS MOVING TO THE NORTH/NORTHEAST AT 50 MPH AND WILL BE NEAR
MAYTOWN BY 245 AND SUBLETTE BY 3 PM CDT.
 
 
GO TO THE BASEMENT OR A SMALL INTERIOR ROOM ON THE LOWEST FLOOR!

What forecasters said that day

The local office's own words before this tornado 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 30, 11:00 AM CDT, 3 hours 41 minutes before
ILZ003>006-008-010>014-019>023-032>033-039-INZ001>005-010>016-019>020-
011100-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHICAGO IL
1100 AM CDT WED APR 30 1997

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

...SEVERE THUNDERSTORMS POSSIBLE THIS AFTERNOON AND EVENING...

THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS NORTH CENTRAL
AND NORTHEAST ILLINOIS AS WELL AS NORTHERN INDIANA.

AT 11 AM CDT THE CENTER OF A STRONG LOW PRESSURE AREA WAS LOCATED OVER
NORTH CENTRAL MISSOURI.  THE LOW IS EXPECTED TO MOVE NORTHEAST TO NEAR
ROCKFORD BY EARLY THIS EVENING...THEN TO NEAR MUSKEGON MICHIGAN BY
AROUND MIDNIGHT.  THIS MEANS THAT MILD AND MORE MOIST AIR OVER THE
MID MISSISSIPPI VALLEY WILL BE DRAWN INTO THE MODERATE RISK AREA
PROVIDING THE INGREDIENTS FOR THUNDERSTORM DEVELOPMENT.

IN ADDITION...WIND VELOCITIES FROM THE GROUND TO MID LEVELS OF THE
ATMOSPHERE WILL BE FAVORABLE FOR SOME OF THESE STORMS TO BECOME
TORNADIC.

PERSONS ACROSS NORTHERN ILLINOIS AND NORTHERN INDIANA SHOULD STAY
ALERT FOR RAPID THUNDERSTORM DEVELOPMENT LATER THIS AFTERNOON AND
LISTEN FOR LATER STATEMENTS REGARDING THIS POTENTIALLY SEVERE WEATHER
SITUATION.

SPOTTER ACTIVATION MAY BE REQUIRED LATER THIS AFTERNOON.

MERZLOCK
Special weather statement, Apr 30, 11:05 AM CDT, 3 hours 36 minutes before
ILZ003>006-008-010>014-019>023-032>033-039-INZ001>005-010>016-019>020-
011100-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHICAGO IL
1100 AM CDT WED APR 30 1997

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

...SEVERE THUNDERSTORMS POSSIBLE THIS AFTERNOON AND EVENING...

THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS NORTH CENTRAL
AND NORTHEAST ILLINOIS AS WELL AS NORTHERN INDIANA.

AT 11 AM CDT THE CENTER OF A STRONG LOW PRESSURE AREA WAS LOCATED OVER
NORTH CENTRAL MISSOURI.  THE LOW IS EXPECTED TO MOVE NORTHEAST TO NEAR
ROCKFORD BY EARLY THIS EVENING...THEN TO NEAR MUSKEGON MICHIGAN BY
AROUND MIDNIGHT.  THIS MEANS THAT MILD AND MORE MOIST AIR OVER THE
MID MISSISSIPPI VALLEY WILL BE DRAWN INTO THE MODERATE RISK AREA
PROVIDING THE INGREDIENTS FOR THUNDERSTORM DEVELOPMENT.

IN ADDITION...WIND VELOCITIES FROM THE GROUND TO MID LEVELS OF THE
ATMOSPHERE WILL BE FAVORABLE FOR SOME OF THESE STORMS TO BECOME
TORNADIC.

PERSONS ACROSS NORTHERN ILLINOIS AND NORTHERN INDIANA SHOULD STAY
ALERT FOR RAPID THUNDERSTORM DEVELOPMENT LATER THIS AFTERNOON AND
LISTEN FOR LATER STATEMENTS REGARDING THIS POTENTIALLY SEVERE WEATHER
SITUATION.

SPOTTER ACTIVATION MAY BE REQUIRED LATER THIS AFTERNOON.

MERZLOCK
Special weather statement, Apr 30, 12:59 PM CDT, 1 hour 42 minutes before
ILZ008-010-011-019-301900-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHICAGO IL
100 PM CDT WED APR 30 1997

...A TORNADO WATCH IS IN EFFECT UNTIL 7 PM CDT...

AT 1 PM CDT RADAR INDICATED SCATTERED SHOWERS ACROSS NORTHWEST AND WEST
CENTRAL ILLINOIS.  THIS AREA OF SHOWERS WAS PRECEDING A LINE OF
THUNDERSTORMS THAT CONTINUES TO INTENSIFY ACROSS SOUTHEAST IOWA AND
NORTHEAST MISSOURI.

THE LINE OF THUNDERSTORMS IS EXPECTED TO BECOME SEVERE AS IT APPROACHES
THE MISSISSIPPI RIVER BY 2 PM.  THIS LINE SHOULD REACH NORTH CENTRAL
ILLINOIS BETWEEN 4 AND 5 PM CDT.

PERSONS SHOULD LISTEN FOR LATER STATEMENTS AND POSSIBLE WARNINGS
CONCERING THIS SEVERE WEATHER SITUATION AND BE PREPARED TO MOVE QUICKLY
TO A PLACE OF SAFETY.

MERZLOCK
Special weather statement, Apr 30, 1:00 PM CDT, 1 hour 41 minutes before
ILZ008-010-011-019-301900-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHICAGO IL
100 PM CDT WED APR 30 1997

...A TORNADO WATCH IS IN EFFECT UNTIL 7 PM CDT...

AT 1 PM CDT RADAR INDICATED SCATTERED SHOWERS ACROSS NORTHWEST AND WEST
CENTRAL ILLINOIS.  THIS AREA OF SHOWERS WAS PRECEDING A LINE OF
THUNDERSTORMS THAT CONTINUES TO INTENSIFY ACROSS SOUTHEAST IOWA AND
NORTHEAST MISSOURI.

THE LINE OF THUNDERSTORMS IS EXPECTED TO BECOME SEVERE AS IT APPROACHES
THE MISSISSIPPI RIVER BY 2 PM.  THIS LINE SHOULD REACH NORTH CENTRAL
ILLINOIS BETWEEN 4 AND 5 PM CDT.

PERSONS SHOULD LISTEN FOR LATER STATEMENTS AND POSSIBLE WARNINGS
CONCERING THIS SEVERE WEATHER SITUATION AND BE PREPARED TO MOVE QUICKLY
TO A PLACE OF SAFETY.

MERZLOCK

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 30, 2:25 PM CDTSevere Thunderstorm WarningLOTLee35 min
Apr 30, 3:05 PM CDTSevere Thunderstorm WarningLOTLaSalle40 min
Apr 30, 3:12 PM CDTSevere Thunderstorm WarningLOTDeKalb48 min
Apr 30, 4:29 PM CDTSevere Thunderstorm WarningLOTFord, Livingston31 min
Apr 30, 5:13 PM CDTTornado WarningLOTLake32 min

Nearby

Tornado Warnings in Illinois, 1997Every tornado warning in 1997Tornadoes 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.