Alert archive / Illinois / Severe Thunderstorm Warnings in 1987

Severe Thunderstorm Warning 21, NWS Chicago, IL

July 26, 1987Kane County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at Jul 26, 1987, 4:35 PM CDT for Kane County, Illinois. It was in force for 55 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: Jul 26, 1987, 4:35 PM CDT (21:35 UTC)
Expired: Jul 26, 1987, 5:30 PM CDT
In force: 55 min
Issued by: NWS Chicago, IL
Area: Whole counties

County Kane County, IL

The radar

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

What was reported inside it

Time	Report	Where	Remark
Jul 26, 5:27 PM CDT	Hail 1.75	Kane, 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. Storm Data before 1996 records only tornadoes, thunderstorm wind and hail.

The nearest sounding before it

Peoria Regional, IL (KPIA), launched 12:00Z, 9.6 hours before the alert went out and 172 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: NaN m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: -10 m²/s²
0-3 km storm-relative helicity: -8 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.2

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KCHI 262135
SVRCHI
ILC089-262230-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE CHICAGO IL
435 PM CDT SUN JUL 26 1987

THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM 
WARNING EFFECTIVE UNTIL 530 PM CDT FOR PEOPLE IN THE FOLLOWING 
COUNTY OF

NORTHEAST ILLINOIS...KANE

AT 430 PM CDT A SEVERE THUNDERSTORM WAS LOCATED IN NORTHERN
DEKALB COUNTY AND WAS MOVING SOUTHEAST AT AROUND 30 MPH.
60 MPH WINDS ACCOMPANIED THIS STORM AS IT PASSED THE ROCKFORD
AREA AT AROUND 415 PM CDT THIS EVENING. THIS STORM SHOULD MOVE
ALONG A PATH FROM HAMPSHIRE... BURLINGTON AREA DURING THE
NEXT HALF HOUR AND THEN TOWARD THW ST. CHARLES AND GENEVA AREA.

IF YOU ARE IN AN AREA THREATENED BY THE STORM..GO TO A REINFORECED
SHELTER AND PREPARE FOR DAMAGING WIND...LARGE HAIL...VERY HEAVY
RAIN AND LIGHTNING.

REMEMBER...SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE
A TORNADO WITH LITTLE OR NO ADVANCE WARNING SO BE ON THE LOOKOUT.

THIS THUNDERSTORM WILL LIKELY PRODUCE WINDS IN EXCESS OF 60
MILES AN HOUR AND HAIL 3/4-INCH OR LARGER IN DIAMETER.

YOU MAY REPORT ANY SEVERE WEATHER SUCH AS TORNADOES...DAMAGING
WINDS...LARGE HAIL...OR FLOODING TO YOUR LOCAL LAW ENFORCEMENT
AGENCY AND ASK THEM TO RELAY YOUR REPORT TO THE NATIONAL WEATHER
SERVICE OFFICE.

2

JJL

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, Jul 26, 1:05 PM CDT, 3 hours 30 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE ROCKFORD IL
105 PM CDT SUN JUL 26 1987

THUNDERSTORMS DEVELOP EARLIER THAN EXPECTED ACROSS NORTHERN ILLINOIS

AT 102 PM CDT... RADAR INDICATED SCATTERED THUNDERSTORMS DEVELOPING
IN AN AREA BOUNDED FROM NEAR DUBUQUE IOWA... TO ROCKFORD... TO 70
SOUTHEAST OF ROCKFORD TO 25 NORTHEAST MOLINE ILLINOIS TO NEAR DUBUQUE
IOWA.  THIS AREA OF NEW THUNDERSTORMS WILL LIKELY MOVE SOUTHEAST AT
30 MPH.

SOME OF THE STRONGER THUNDERSTORMS WERE LOCATED IN OGLE AND LEE
COUNTIES... ABOUT 30 SOUTHWEST OF ROCKFORD... JUST WEST OF OREGON
ANOTHER ABOUT 35 SOUTH SOUTHWEST OF ROCKFORD... NEAR AMBOY ILLINOIS.
PERSONS IN NORTHERN ILLINOIS SHOULD BE ALERT THROUGH THE AFTERNOON
AND EVENING HOURS AS THE THUNDERSTORM AREA CONTINUES TO DEVELOP.

NO... SEVERE WEATHER HAS BEEN REPORT WITH THESE STORMS HOWEVER...
IF SEVERE WEATHER IS OBSERVED TAKE SHELTER IN A STURDY STRUCTURE AWAY
FROM WINDOWS AND DOORS.

ISP DIST. 1.. 16
PIERCE

Special weather statement, Jul 26, 1:12 PM CDT, 3 hours 23 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE ROCKFORD IL
110 PM CDT SUN JUL 26 1987

       ... STRONG THUNDERSTORMS MOVING TOWARD DIXON ILLINOIS...

AT 108 PM CDT... RADAR INDICATED A STRONG THUNDERSTORM JUST NORTHWEST
OF DIXON ILLINOIS... THAT ABOUT 40 SOUTHWEST OF ROCKFORD.  THIS IS
A THUNDERSTORM... PART OF AN AREA OF DEVELOPING STORMS IN NORTHERN
ILLINOIS.  MOVEMENT IS SOUTHEAST AT ABOUT 30 MPH.

PERSONS IN SOUTHWEST OGLE AND NORTHWEST LEE COUNTY... IN THE VICINITY
OF DIXON... POLO... FRANKLIN GROVE AND AMBOY... EXPECT GUSTY WINDS...
POSSIBLY TO 40 MPH... HAIL AND HEAVY RAIN.

NO... SEVERE WEATHER HAS BEEN REPORT WITH THESE STORMS HOWEVER...
IF SEVERE WEATHER IS OBSERVED TAKE SHELTER IN A STURDY STRUCTURE AWAY
FROM WINDOWS AND DOORS.

ISP DIST. 1
PIERCE

Special weather statement, Jul 26, 2:15 PM CDT, 2 hours 20 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHICAGO IL
2 15 PM CDT SUN JUL 28 1987

   ...SEVERE THUNDERSTORM WATCH UNTIL 9 PM...
   ...THUNDERSTORMS DEVELOPING RAPIDLY OVER IROQUOIS COUNTY...

A SEVERE THUNDERSTORM WATCH HAS BEEN ISSUED FOR NORTHERN ILLINOIS
UNTIL 9 PM. THIS INCLUDES ALL OF THE CHICAGO METROPOLITAN AREA.
CONDITIONS ARE FAVORABLE THIS AFTERNOON FOR THE FORMATION OF SEVERE
THUNDERSTORMS WITH LARGE HAIL AND DAMAGING WINDS.

AT 2 15 PM... THUNDERSTORMS WERE DEVLOPING ACROSS NORTHERN ILLINOIS.
THE LINE OF STORMS EXTENDED FROM 15 MILES NORTH OF LAFAYETTE INDIANA...
SOUTHWEST TO MANSFIELD ILLINOIS IN PIATT COUNTY...17 MILES NORTHWEST OF
CHAMPAIGN. THE HEAVIEST THUNDERSTORM WAS LOCATED NEAR 10 MILES NORTH
OF CHAMPAIGN IN SOUTHERN FORD COUNTY...BETWEEN PAXTON AND GIBSON CITY.
THE STORMS WERE MOVING SOUTHEAST AT 30 MILES PER HOUR. ANOTHER LINE
OF STRONG THUNDERSTORMS IS DEVELOPING RAPIDLY ACROSS NORTHEAST HIOWA
AND WILL SWEEP ACROSS NORTHERN ILLINOIS THE NEXT SEVERAL HOURS.

Special weather statement, Jul 26, 2:44 PM CDT, 1 hour 51 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE ROCKFORD IL
245 PM CDT SUN JUL 26 1987

     ... STRONG THUNDERSTORMS DEVELOPING IN NORTHERN ILLINOIS ...
     ... SEVERE THUNDERSTORM WATCH  436 IN EFFECT UNTIL 10 PM ...

AT 142 PM CDT... RADAR INDICATED A STRONG THUNDERSTORM... SCATTERED
IN A LINE FROM NORTHEAST IOWA... SOUTHEAST TO ABOUT 25 MILES NORTH-
EAST OF DUBUQUE IOWA... TO NEAR FREEPORT ILLINOIS... ON SOUTHEAST TO
EAST CENTRAL ILLINOIS... WELL SOUTH OF CHICAGO.  MOVEMENT OF
THE THUNDERSTORMS WAS IS SOUTHEAST AT ABOUT 30 MPH.

PERSONS IN NORTHERN ILLINOIS... ESPECIALLY NEAR FREEPORT... LENA...
OREGON... FORRESTON TOWARD DIXON... OF NORTHERN ILLINOIS BE ALERT FOR
THESE STORMS.  ANOTHER STRONG STORM HAS DEVELOPED 20 MILES SOUTHEAST
OF DEKALB ILLINOIS NEAR PLANO ILLINOIS IN KENDALL COUNTY.   THE
STRONGER STORMS... EXPECT GUSTY WINDS... POSSIBLY TO 40 MPH... SMALL
HAIL AND HEAVY RAIN.

NO... SEVERE WEATHER HAS BEEN REPORT WITH THE ILLINOIS STORMS...
IF SEVERE WEATHER IS OBSERVED TAKE SHELTER IN A STURDY STRUCTURE AWAY
FROM WINDOWS AND DOORS.  WHEN THE STORM IS PAST... PLEASE REPORT ANY
SEVERE WEATHER TO LOCAL LAW ENFORCEMENT FOR RELAY TO THE NATIONAL
WEATHER SERVICE.
W
ISP DIST. 1... 16
PIERCE

Special weather statement, Jul 26, 2:48 PM CDT, 1 hour 47 minutes before

SPECIAL WEATHER STATEMENT             ...CORRECTION TO RADAR TIME...
NATIONAL WEATHER SERVICE ROCKFORD IL
245 PM CDT SUN JUL 26 1987

    ... STRONG THUNDERSTORMS DEVELOPING IN NORTHERN ILLINOIS ...
    ... SEVERE THUNDERSTORM WATCH  436 IN EFFECT UNTIL 10 PM ...

AT 242 PM CDT... RADAR INDICATED A STRONG THUNDERSTORM... SCATTERED
IN A LINE FROM NORTHEAST IOWA... SOUTHEAST TO ABOUT 25 MILES NORTH-
EAST OF DUBUQUE IOWA... TO NEAR FREEPORT ILLINOIS... ON SOUTHEAST TO
EAST CENTRAL ILLINOIS... WELL SOUTH OF CHICAGO.  MOVEMENT OF
THE THUNDERSTORMS WAS IS SOUTHEAST AT ABOUT 30 MPH.

PERSONS IN NORTHERN ILLINOIS... ESPECIALLY NEAR FREEPORT... LENA...
OREGON... FORRESTON TOWARD DIXON... OF NORTHERN ILLINOIS BE ALERT FOR
THESE STORMS.  ANOTHER STRONG STORM HAS DEVELOPED 20 MILES SOUTHEAST
OF DEKALB ILLINOIS NEAR PLANO ILLINOIS IN KENDALL COUNTY.   THE
STRONGER STORMS... EXPECT GUSTY WINDS... POSSIBLY TO 40 MPH... SMALL
HAIL AND HEAVY RAIN.
`

NO... SEVERE WEATHER HAS BEEN REPORT WITH THE ILLINOIS STORMS...
IF SEVERE WEATHER IS OBSERVED TAKE SHELTER IN A STURDY STRUCTURE AWAY
FROM WINDOWS AND DOORS.  WHEN THE STORM IS PAST... PLEASE REPORT ANY
SEVERE WEATHER TO LOCAL LAW ENFORCEMENT FZOR RELAY TO THE NATIONAL
WEATHER SERVICE.

ISP DIST. 1... 16
PIERCE

Special weather statement, Jul 26, 3:32 PM CDT, 1 hour 3 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHICAGO IL
3 30 PM CDT SUN JUL 28 1987

  ...SEVERE THUNDERSTORM WATCH UNTIL 9 PM...
...THUNDERSTORMS LINING UP FROM WEST OF ROCKFORD TO NEAR CHAMPAIGN...

A SEVERE THUNDERSTORM WATCH CONTINUES IN EFFECT FOR MOST OF NORTHERN
ILLINOIS UNTIL 9 PM. THIS INCLUDES ALL OF THE CHICAGO METROPOLITAN
AREA. A WATCH MEANS CONDITIONS ARE FAVORABLE FOR THE FORMATION OF
SEVERE THUNDERSTORMS WITH LARGE HAIL AND DAMAGING WINDS.

AT 3 PM... THUNDERSTORMS HAD DEVLOP ACROSS NORTHERN ILLINOIS FROM WEST
OF ROCKFORD TO NEAR CHAMPAIGN INCLUDING THE FAR WEST AND SOUTHWEST
PORTIONS OF THE CHICAGO METROPOLITAN AREA. THERE HAVE BEEN REPORTS OF
HAIL AND FUNNEL CLOUDS BUT NORTHING SO FAR IN THE CHICAGO METROPOLITAN
AREA. THESE STORMS WERE MOVING SOUTHEAST AT 30 MILES PER HOUR. AT THIS
TIME... THE WEST AND SOUTH SUBURBS ARE THE MOST LIKELY AREAS FOR
THUNDERSTORMS WITHIN THE NEXT HOUR OR SO.
WILLIAMS

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 26, 5:10 PM CDT	Severe Thunderstorm Warning	LOT	Kane, McHenry	50 min
Jul 26, 5:30 PM CDT	Severe Thunderstorm Warning	LOT	Cook, Kane, McHenry	60 min
Jul 26, 5:30 PM CDT	Severe Thunderstorm Warning	LOT	DuPage	60 min
Jul 26, 6:08 PM CDT	Severe Thunderstorm Warning	LOT	Cook, Lake	32 min

Nearby

Severe Thunderstorm Warnings in Illinois, 1987 Every severe thunderstorm warning in 1987

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.