Alert archive / Illinois / Tornado Warnings in 1998

Tornado Warning 13, NWS Chicago, IL

August 24, 1998Boone County, DeKalb County, Illinois

NWS Chicago, IL issued this tornado warning at Aug 24, 1998, 12:52 PM CDT for Boone County, DeKalb County, Illinois. It was in force for 53 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
Aug 24, 1998, 12:52 PM CDT (17:52 UTC)
Expired
Aug 24, 1998, 1:45 PM CDT
In force
53 min
Issued by
NWS Chicago, IL
Area
Whole counties

Counties Boone County, IL, DeKalb County, IL

The radar

The Chicago radar (KLOT), 81 km from the middle of the area, began a volume at 17:52 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
Aug 24, 1:07 PM CDTThunderstorm Wind 50Kirkland, 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 watch it was issued in

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

IssuedProductOfficeLasted
Aug 24, 10:15 AM CDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 5.9 hours before the alert went out and 151 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 1998-08-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2161 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, Davenport, at 12:00Z on 1998-08-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 54 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
2161 J/kg
Mixed-layer CIN
-158 J/kg
Mixed-layer LCL
1178 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
54 m²/s²
0-3 km storm-relative helicity
128 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.1

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KCHI 241752 RRA
TORCHI
ILC007-037-241848-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE CHICAGO IL
1252 PM CDT MON AUG 24 1998

THE NATIONAL WEATHER SERVICE IN CHICAGO HAS ISSUED A

* TORNADO WARNING FOR...
  BOONE COUNTY IN NORTH CENTRAL ILLINOIS
  DE KALB COUNTY IN NORTH CENTRAL ILLINOIS

* UNTIL 145 PM CDT

* AT 1250 PM...RADAR INDICATED A TORNADO NEAR KISHWAUKEE OR 8 MILES
  SOUTH OF ROCKFORD...MOVING EAST-SOUTHEAST 45 MPH.

* TfOWN IN THE PATH OF THE TORNADO ARE...
  NEW MILFORD
  MONROE CENTER
  IRENE 
  KINGSTON
  GENOA

GO TO THE BASEMENT OR A SMALL INTERIOR ROOM ON THE LOWEST FLOOR!

JT

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 24, 12:19 PM CDTSevere Thunderstorm WarningLOTOgle, Winnebago51 min
Aug 24, 12:37 PM CDTTornado WarningLOTOgle, Winnebago33 min
Aug 24, 12:44 PM CDTSevere Thunderstorm WarningLOTLee55 min
Aug 24, 1:14 PM CDTSevere Thunderstorm WarningLOTKane, McHenry31 min
Aug 24, 1:28 PM CDTSevere Thunderstorm WarningLOTCook, DuPage, Kendall, Will62 min
Aug 24, 1:28 PM CDTSevere Thunderstorm WarningLOTLake62 min
Aug 24, 2:09 PM CDTSevere Thunderstorm WarningLOTWill51 min
Aug 24, 2:26 PM CDTSevere Thunderstorm WarningLOTKankakee54 min

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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.