Alert archive / Illinois / Tornado Warnings in 1998

Tornado Warning 11, NWS Chicago, IL

June 25, 1998McHenry County, Illinois

NWS Chicago, IL issued this tornado warning at Jun 25, 1998, 9:26 PM CDT for McHenry 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
Jun 25, 1998, 9:26 PM CDT (02:26 UTC)
Expired
Jun 25, 1998, 10:00 PM CDT
In force
34 min
Issued by
NWS Chicago, IL
Area
Whole counties

County McHenry County, IL

The watch it was issued in

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

IssuedProductOfficeLasted
Jun 25, 7:30 PM CDTSevere Thunderstorm WatchSPC5 hr

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 2.4 hours before the alert went out and 187 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 00:00Z on 1998-06-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3869 joules per kilogram.LCLLFCEL10008507005003002001001 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 00:00Z on 1998-06-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 87 square meters per square second.193958Sfc1 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
3869 J/kg
Mixed-layer CIN
-8 J/kg
Mixed-layer LCL
1276 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
87 m²/s²
0-3 km storm-relative helicity
185 m²/s²
Significant tornado parameter
1.3
Supercell composite
9.7

Open this sounding in Storm Lab

The text

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

263 
WFUS1 KCHI 260231 RRA
TORCHI
ILC111-260326-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE CHICAGO IL
926 PM CDT THU JUN 25 1998



THE NATIONAL WEATHER SERVICE IN CHICAGO HAS ISSUED A

* TORNADO WARNING FOR...
  WESTERN MCHENRY COUNTY IN NORTHEAST ILLINOIS

* UNTIL 1000 PM CDT

* AT 925 PM CDT A POSSIBLE TORNADO WAS INDICATED BY RADAR NEAR POPLAR
  GROVE OR ABOUT 20 MILES WEST OF WOODSTOCK.

* THIS STORM WILL BE NEAR HARVARD BY 940 PM.

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, Jun 25, 4:15 PM CDT, 5 hours 11 minutes before
ILZ005>006-012>014-020-022-INZ001-251100-

HEAT WARNING
NATIONAL WEATHER SERVICE CHICAGO IL
415 PM CDT THU JUN 25 1998

...HEAT WARNING FOR THE CHICAGO METROPOLITAN AREA
THROUGH FRIDAY AND MAY BE EXTENDED THROUGH THE
WEEKEND...

THE HEAT WARNING INCLUDES THE FOLLOWING COUNTIES...
  IN ILLINOIS...COOK DUPAGE KANE KENDALL LAKE MCHENRY
AND WILL. THIS INCLUDES THE CITIES/TOWNS OF CHICAGO
WHEATON AURORA WAUKEGAN WOODSTOCK AND JOLIET.
  IN INDIANA...LAKE. THIS INCLUDES THE CITY/TOWN OF GARY.

A HEAT WARNING WILL REMAIN IN EFFECT FOR METROPOLITAN
CHICAGO AT LEAST THROUGH FRIDAY AND MAY REMAIN IN
EFFECT THROUGH THE WEEKEND.

TONIGHTS LOW SHOULD REMAIN ABOVE 75...CLOSER TO 80 IN
DOWNTOWN CHICAGO WITH HEAT INDICES REMAINING ABOVE 80.
HEAT INDICES FRIDAY WILL AGAIN CLIMB AS HIGH AS 105.
PRESENTLY WE EXPECT SIMILAR CONDITIONS FRIDAY NIGHT AND
SATURDAY SO THE WARNING MAY BE EXTENDED ANOTHER DAY.

THIS IS A LIFE THREATENING HEAT WAVE ESPECIALLY IN
DENSELY POPULATED URBAN AREAS. PEOPLE MOST AT RISK
ARE THE ELDERLY AND THOSE WITH CHRONIC HEALTH
PROBLEMS. THE BEST WAY TO SURVIVE THE HEAT IS TO SPEND
AS MUCH TIME AS POSSIBLE IN AIR CONDITIONING... DRINK
PLENTY OF WATER OR FRUIT JUICES AND CURTAIL STRENUOUS
ACTIVITIES.

FOR CITY OF CHICAGO HEAT SERVICES CALL...312-744-5000.

KAPLAN
Special weather statement, Jun 25, 4:15 PM CDT, 5 hours 11 minutes before
ILZ005>006-012>014-020-022-INZ001-251100-

HEAT WARNING
NATIONAL WEATHER SERVICE CHICAGO IL
415 PM CDT THU JUN 25 1998

...HEAT WARNING FOR THE CHICAGO METROPOLITAN AREA
THROUGH FRIDAY AND MAY BE EXTENDED THROUGH THE
WEEKEND...

THE HEAT WARNING INCLUDES THE FOLLOWING COUNTIES...
  IN ILLINOIS...COOK DUPAGE KANE KENDALL LAKE MCHENRY
AND WILL. THIS INCLUDES THE CITIES/TOWNS OF CHICAGO
WHEATON AURORA WAUKEGAN WOODSTOCK AND JOLIET.
  IN INDIANA...LAKE. THIS INCLUDES THE CITY/TOWN OF GARY.

A HEAT WARNING WILL REMAIN IN EFFECT FOR METROPOLITAN
CHICAGO AT LEAST THROUGH FRIDAY AND MAY REMAIN IN
EFFECT THROUGH THE WEEKEND.

TONIGHTS LOW SHOULD REMAIN ABOVE 75...CLOSER TO 80 IN
DOWNTOWN CHICAGO WITH HEAT INDICES REMAINING ABOVE 80.
HEAT INDICES FRIDAY WILL AGAIN CLIMB AS HIGH AS 105.
PRESENTLY WE EXPECT SIMILAR CONDITIONS FRIDAY NIGHT AND
SATURDAY SO THE WARNING MAY BE EXTENDED ANOTHER DAY.

THIS IS A LIFE THREATENING HEAT WAVE ESPECIALLY IN
DENSELY POPULATED URBAN AREAS. PEOPLE MOST AT RISK
ARE THE ELDERLY AND THOSE WITH CHRONIC HEALTH
PROBLEMS. THE BEST WAY TO SURVIVE THE HEAT IS TO SPEND
AS MUCH TIME AS POSSIBLE IN AIR CONDITIONING... DRINK
PLENTY OF WATER OR FRUIT JUICES AND CURTAIL STRENUOUS
ACTIVITIES.

FOR CITY OF CHICAGO HEAT SERVICES CALL...312-744-5000.

KAPLAN

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 25, 8:22 PM CDTSevere Thunderstorm WarningLOTWinnebago63 min
Jun 25, 8:41 PM CDTTornado WarningLOTWinnebago44 min
Jun 25, 8:59 PM CDTSevere Thunderstorm WarningLOTBoone, McHenry56 min
Jun 25, 8:59 PM CDTSevere Thunderstorm WarningLOTLake56 min
Jun 25, 9:14 PM CDTTornado WarningLOTLake, McHenry31 min
Jun 26, 12:20 AM CDTFlash Flood WarningLOTBoone, Winnebago6 hr
Jun 26, 12:20 AM CDTFlash Flood WarningLOTLake, McHenry6 hr
Jun 26, 2:50 AM CDTSevere Thunderstorm WarningLOTCook, DuPage, Will40 min
Jun 26, 3:45 AM CDTSevere Thunderstorm WarningLOTCook, Will60 min
Jun 26, 11:08 AM CDTFlash Flood WarningLOTBoone7 hr
Jun 26, 6:00 PM CDTFlash Flood WarningLOTBoone12 hr

Nearby

Tornado Warnings in Illinois, 1998Every tornado warning in 1998Tornadoes in 1998

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.