Alert archive / Illinois / Tornado Warnings in 1990

Tornado Warning 2, NWS Chicago, IL

June 17, 1990Grundy County, Illinois

NWS Chicago, IL issued this tornado warning at Jun 17, 1990, 7:17 PM CDT for Grundy County, Illinois. It was in force for 18 min.

The area

The counties it named.

The facts

Issued
Jun 17, 1990, 7:17 PM CDT (00:17 UTC)
Expired
Jun 17, 1990, 7:35 PM CDT
In force
18 min
Issued by
NWS Chicago, IL
Area
Whole counties

County Grundy County, IL

The radar

The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.

The nearest sounding before it

Green Bay/Straub, WI (KGRB), launched 00:00Z, 0.3 hours before the alert went out and 356 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, Green Bay/Straub, WI at 00:00Z on 1990-06-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 49 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Green Bay/Straub, WI at 00:00Z on 1990-06-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 68 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
49 J/kg
Mixed-layer CIN
-98 J/kg
Mixed-layer LCL
1611 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
68 m²/s²
0-3 km storm-relative helicity
100 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.5

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KCHI 180021 COR
TORCHI
ILC063-099-180100-

BULLETIN - EBS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE CHICAGO IL
717 PM CDT SUN JUN 17 1990

THE NATIONAL WEATHER SERVICE IN CHICAGO HAS ISSUED A
TORNADO WARNING EFFECTIVE UNTIL  800 PM CDT
FOR PEOPLE IN THE FOLLOWING COUNTIES...

IN NORTHEAST ILLINOIS
          ...NORTHERN GRUNDY...EAST CENTRAL LASALLE

AT 710 PM A POSSIBLE TORNADO WAS OBSERVED NEAR INTERSTATE 80 NORTH
OF THE TOWN OF MARSEILLES...WHICH IS ABOUT 45 MILES WEST NORTHWEST
OF KANKAKEE. THE STORM WAS MOVING EAST AT 30 MPH. TOWNS IN THE PATH
OF THIS STORM INCLUDE MARSEILLES AND MORRIS.

IF YOU ARE IN THE PATH OF A TORNADO...THE SAFEST PLACE IS A
BASEMENT.  GET UNDER A WORKBENCH O%R PIECE OF STURDY FURNITURE.
IF NO BASEMENT IS AVAILABLE...SEEK SHELTER IN AN INTERIOR ROOM
SUCH AS A CLOSET ON THE LOWEST FLOOR.  USE BLANKETS...PILLOWS...
OR CUSHIONS TO COVER YOUR BODY.  AVOID WINDOWS.

PURPURA

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, Jun 17, 4:39 PM CDT, 2 hours 38 minutes before
ILZ-001-002-172230

NATIONAL WEATHER SERVICE ROCKFORD IL
SPECIAL WEATHER STATEMENT
4 40 PM CDT SUN JUN 17 1990

...TONADO WATCH FOR NORTHERN ILLINOIS UNTIL 10 PM...

AT 4 30 PM CDT...RADAR INDICATED A SEVERE THUNDERSTORM ACROSS THE
SOUTHERN PART OF WHITESIDE COUNTY...NEAR PROPHETSTOWN...WHICH IS
ABOUT 25 MILES NORTHEAST OF MOLINE...ILLINOIS. SO FAR...NO REPORTS OF
SEVERE WEATHER HAVE BEEN RECEIVED FROM THIS STROM. THE STORM WAS MOVING
TO THE NORTHEAST AT 30 MPH...AND SHOULD PASS NEAR ROCK FALLS AND INTO
WESTERN LEE COUNTY NEAR HARMON WITHIN THE NEXT HALF HOUR.

CONDITIONS COUNTINUE TO REMAIN VERY UNSTABLE AND THNUDERSTORMS COULD
DEVELOP AND BECOME SEVERE AT ANY TIME WITH THE POSSIBLITY OF A TORNADO.
EVERYONE ACROSS NORTHERN ILLINOIS SHOULD BE PREPARED TO MOVE TO A PLACE
OF SAFETY IF CONDITIONS BECOME THREATENING...AND SHOULD LISTEN FOR
LATER STATEMENTS AND POSSIBLE WARNINGS DURING THE EVENING.

ATTN IST DIST...1...2...16.
SANDERS
Special weather statement, Jun 17, 5:12 PM CDT, 2 hours 5 minutes before
ILZ-001-002-172300

NATIONAL WEATHER SERVICE ROCKFORD IL
SPECIAL WEATHER STATEMENT
5 12 PM CDT SUN JUN 17 1990

...TONADO WATCH FOR NORTHERN ILLINOIS UNTIL 10 PM...

AT 5 PM CDT...RADAR INDICATED A STRONG THUNDERSTORM ENTERING THE
WESTERN HALF OF LEE COUNTY. THE MOST INTENSE PART OF THE STORM WAS
ABOUT 10 MILES WEST SOUTHWEST OF MAYTOWN...WHICH IS ABOUT 55 MILES
SOUTHWEST OF ROCKFORD. NO SEVERE WEATHER WAS REPORTED WITH THIS STORM
WHEN IT WAS IN WHITESIDE COUNTY...AND THE STROM HAS DECREASED IN
INTENSITY DURING THE LAST 30 MINUTES.

THE TREND FOR THUNDERSTORM DEVELOPMENT HAS SHIFTED SOUTHWARD INTO
CENTRAL ILLINOIS DURING THE LAST HALF HOUR...ALTHOUGH CONDITIONS IN
NORTHERN ILLINOIS REMAIN UNSTABLE ENOUGH FOR THUNDERSTORMS TO DEVELOP
AND BECOME SEVERE.  EVREYONE ACROSS NORTHERN ILLINOIS SHOULD CONTINUE
TO LISTEN FOR LATER STATEMENTS AND POSSIBLE WARNINGS DURING THE EVENING.
ATTN IST DIST...1...2...16.
SANDERS
Special weather statement, Jun 17, 5:36 PM CDT, 1 hour 41 minutes before
ILZ-001-002-172330

NATIONAL WEATHER SERVICE ROCKFORD IL
SPECIAL WEATHER STATEMENT
5 35 PM CDT SUN JUN 17 1990

...TORNADO WATCH FOR WINNEBAGO...BOONE...OGLE...LEE...AND
   DE KALB COUNTIES CONTINUE UNTIL 10 PM...
...TORNADO WATCH FOR JO DAVIS...CARROLL...AND STEPHENSON
   COUNTIES HAS BEEN CANCELED...

AT 5 30 PM CDT...A COLD FRONT WAS MOVING ACROSS THE NORTHWESTERN
CORNER OF ILLINOIS...WHICH HAS ENDED THE THREAT OF SEVERE WEATHER
FOR THAT AREA. MEANWHILE...RADAR INDICATED A VERY STRONG THUNDERSTORM
ALONG THE LEE AND BUREAU COUNTY LINE. THE MOST INTENSE PART OF THE
STORM REMAINED IN BUEARU COUNTY...NEAR THE TOWN OF VAN ORIN...
WHICH IS ABOUT 55 MILES SOUTH OF ROCKFORD. THE STORM IS NOW MOVING
ALMOST STRAIGHT EAST AT 35 TO 40 MPH...AND TAKE THE STRONGEST PART
OF THE STORM SOUTH OF LEE AND DE KALB COUNTIES.

NO OTHER THUNDERSTORMS WERE INDICATED OVER THE REST OF NORTHERN
ILLINOIS...HOWEVER THUNDERSTORMS COULD STILL DEVELOP AND
BECOME SEVERE MAINLY TO THE EAST AND SOUTH OF ROCKFORD
DURING THE NEXT SEVERAL HOURS.

ATTN ISP DIST...1...2...16.
SANDERS
Special weather statement, Jun 17, 5:48 PM CDT, 1 hour 29 minutes before
ILZ003-180000-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHICAGO IL
5 45 PM CDT SUN JUN 17 1990

A TORNADO WATCH IS IN EFFECT FOR NORTHERN AND CENTRAL ILLINOIS
UNTIL 10 PM CDT.

SCATTERED THUNDERSTORMS HAVE DEVELOPED IN BANDS THROUGH THE EAST
HALF OF NORTHERN ILLINOIS SOUTHWEST TOWARD ST. LOUIS. THE STORMS
ARE MOVING EAST AT 30 MPH.

THE AIRMASS REMAINS VERY HOT AND HUMID..AND THERE IS STILL THE POTENTIAL
FOR SOME OF THESE STORMS TO BECOME SEVERE. PEOPLE IN THE WATCH AREA
SHOULD BE PREPARED FOR RAPIDLY DEVELOPING STORMS AND TAKE SHELTER IF
THREATENING WEATHER APPROACHES.

STAY TUNED TO NOAA WEATHER RADIO...OR LOCAL RADIO AND TELEVISION
STATIONS FOR UPDATES ON THE POSSIBILITY FOR SEVERE WEATHER.

HOLLINGSWORTH
Special weather statement, Jun 17, 6:17 PM CDT, 1 hour before
ILZ-001-002-180030

NATIONAL WEATHER SERVICE ROCKFORD IL
SPECIAL WEATHER STATEMENT
6 17 PM CDT SUN JUN 17 1990

...TORNADO WATCH FOR WINNEBAGO...BOONE...OGLE...LEE...AND
   DE KALB COUNTIES HAS BEEN CANCELED...AS WELL AS THE REST
   ON NORTHERN ILLINOIS...

AT 6 10 PM CDT...A COLD FRONT WAS MOVING RAPIDLY EASTWARD ACROSS THE
ROCKFORD AREA AND INTO NORTHEASTERN ILLINOIS. THIS HAS ENDED THE THREAT
OF SEVERE WEATHER FOR NORTHERN ILLINOIS. RADAR INDICATED A VERY STRONG
THUNDERSTORM ALONG THE DE KALB AND LA SALLE COUNTY LINE...WHICH WAS
MOVING EAST AT 35 TO 40 MPH. THE STORM SHOWS SIGNS OF DEVELOPING
NORTHWARD INTO CENTRAL DE KALB COUNTY WHICH COULD PRODUCE VERY STRONG
WINDS AND POSSIBLE HAIL FOR THAT AREA FOR THE NEXT 30 MINUTES...UNTIL
THE STORM TO THE EAST INTO KANE AND KENDALL COUNTIES.

NO OTHER THUNDERSTORMS WERE INDICATED OVER THE REST OF NORTHERN
ILLONOIS AND NONE WILL BE EXPECTED FOR THE REST OF TONIGHT.

ATTN ISP DIST...1...2...16.
SANDERS
Special weather statement, Jun 17, 6:36 PM CDT, 41 minutes before
ILZ003-180030-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHICAGO IL
6 35 PM CDT SUN JUN 17 1990

AT 6 30PM A STRONG THUNDERSTORM WAS INDICATED BY RADAR IN NORTHERN
LASALLE COUNTY NEAR EARLVILLE...WHICH IS ABOUT 35 MILES WEST SOUTHWEST
OF AURORA...MOVING EAST AT 35 TO 40 MPH.

TOWNS IN THE PATH OF THIS STORM IN NORTH LASALLE...NORTH KENDALL
...AND SOUTH KANE COUNTIES INCLUDE LELAND...SANDWICH...PLANO...
BRISTOL...AND MONTGOMERY. THE STORM COULD EFFECT AURORA BY 7 15 PM.

INTENSE LIGHTNING...HEAVY RAIN...HAIL AND STRONG WINDS ARE LIKELY
WITH THIS STORM. PERSONS IN THIS AREA SHOULD BE ALERT FOR THE
POSSIBILITY OF SEVERE WEATHER AND STAY TUNED TO LOCAL MEDIA FOR
WEATHER UPDATES.

HOLLINGSWORTH

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 17, 7:03 PM CDTSevere Thunderstorm WarningLOTLaSalle32 min
Jun 17, 7:03 PM CDTSevere Thunderstorm WarningLOTKendall42 min
Jun 17, 7:17 PM CDTTornado WarningLOTLaSalle43 min
Jun 17, 8:45 PM CDTSevere Thunderstorm WarningLOTKankakee, Will45 min

Nearby

Tornado Warnings in Illinois, 1990Every tornado warning in 1990Tornadoes in 1990

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.