Alert archive / Illinois / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 21, NWS Chicago, IL

May 12, 1998Lee County, Ogle County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at May 12, 1998, 10:05 PM CDT for Lee County, Ogle County, Illinois. It was in force for 60 min. 3 reports 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
May 12, 1998, 10:05 PM CDT (03:05 UTC)
Expired
May 12, 1998, 11:05 PM CDT
In force
60 min
Issued by
NWS Chicago, IL
Area
Whole counties

Counties Lee County, IL, Ogle County, IL

What was reported inside it

TimeReportWhereRemark
May 12, 10:28 PM CDTHail 0.75Oregon, IL
May 12, 10:30 PM CDTHail 1Amboy, ILSome residents in the western part of the county sustained to their homes as winds and large hail brokewindows. A garage was blown off its foundation and shifted. The roof of another garage was blown off.
May 12, 11:03 PM CDTHail 0.75Paw Paw, 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
May 12, 7:30 PM CDTTornado WatchSPC6 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 3.1 hours before the alert went out and 203 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, Lincoln, IL at 00:00Z on 1998-05-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1906 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, Lincoln, IL at 00:00Z on 1998-05-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 81 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
1906 J/kg
Mixed-layer CIN
-10 J/kg
Mixed-layer LCL
1317 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
81 m²/s²
0-3 km storm-relative helicity
190 m²/s²
Significant tornado parameter
0.7
Supercell composite
6.2

Open this sounding in Storm Lab

The text

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

552 
WUUS1 KCHI 130308 RRA
SVRCHI
ILC103-141-130404-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE CHICAGO IL
1005 PM CDT TUE MAY 12 1998

THE NATIONAL WEATHER SERVICE IN CHICAGO HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  LEE COUNTY IN NORTH CENTRAL ILLINOIS
  OGLE COUNTY IN NORTH CENTRAL ILLINOIS

* UNTIL 1105 PM CDT

* AT 1005 PM CDT SEVERE THUNDERSTORMS WERE LOCATED FROM 5
  MILES WEST OF DIXON TO NEAR WALNUT IN WESTERN LEE COUNTY.
 THE STORMS WERE MOVING TO THE NORTHEAST AT 40 MPH.

* THE SEVERE THUNDERSTORMS WILL BE NEAR...
  AMBOY AND OREGON AT 1025 PM 

THIS IS A DANGEROUS STORM STAY INDOORS...AWAY FROM WINDOWS

$$
KAHN/ALLSOPP

The office that day

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

IssuedProductOfficeCountiesLasted
May 12, 7:07 PM CDTSevere Thunderstorm WarningLOTGrundy, Kendall23 min
May 12, 7:07 PM CDTSevere Thunderstorm WarningLOTGrundy, Kendall83 min
May 12, 8:11 PM CDTSevere Thunderstorm WarningLOTLaSalle49 min
May 12, 8:42 PM CDTSevere Thunderstorm WarningLOTDeKalb53 min
May 12, 9:09 PM CDTSevere Thunderstorm WarningLOTKane61 min
May 12, 9:38 PM CDTSevere Thunderstorm WarningLOTLake, McHenry62 min
May 12, 9:46 PM CDTSevere Thunderstorm WarningLOTLee44 min
May 12, 10:20 PM CDTSevere Thunderstorm WarningLOTLake25 min
May 12, 11:03 PM CDTSevere Thunderstorm WarningLOTDeKalb, LaSalle57 min

Nearby

Severe Thunderstorm Warnings in Illinois, 1998Every severe thunderstorm warning 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.