Alert archive / Illinois / Severe Thunderstorm Warnings in 1990

Severe Thunderstorm Warning 21, NWS Chicago, IL

June 30, 1990Cook County, Will County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at Jun 30, 1990, 5:44 PM CDT for Cook County, Will County, Illinois. It was in force for 61 min.

The area

The counties it named.

The facts

Issued
Jun 30, 1990, 5:44 PM CDT (22:44 UTC)
Expired
Jun 30, 1990, 6:45 PM CDT
In force
61 min
Issued by
NWS Chicago, IL
Area
Whole counties

Counties Cook County, IL, Will 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 12:00Z, 10.7 hours before the alert went out and 313 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 12:00Z on 1990-06-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 138 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, Green Bay/Straub, WI at 12:00Z on 1990-06-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 114 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
138 J/kg
Mixed-layer CIN
-220 J/kg
Mixed-layer LCL
1486 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
114 m²/s²
0-3 km storm-relative helicity
95 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.8

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KCHI 302244
SVRCHI
ILC031-197-302345-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING 
NATIONAL WEATHER SERVICE CHICAGO IL
544 PM CDT SAT JUN 30 1990

THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM 
WARNING EFFECTIVE UNTIL 645 PM CDT FOR PEOPLE IN THE FOLLOWING 
COUNTIES

   IN THE NORTHEAST PART OF ILLINOIS
      SOUTHERN COOK...WILL

AT 5 40 PM CDT RADAR SHOWED A SEVERE THUNDERSTORM INTENSIFING 12
MILES NORTH OF JOLIET. THIS STORM WAS MOVING SOUTHEAST AT 35 MPH.

TOWNS IN THE PATH OF THIS STORM ARE LOCKPORT...FRANKFORT...TINLEY
PARK AND PARK FOREST.

IF YOU ARE IN AN AREA THREATENED BY THIS STORM...GO TO A REINFORCED
SHELTER AND PREPARE FOR DAMAGING WIND...LARGE H;AIL..VERY HEAVY RAIN
AND LIGHTNING.

SIMPSON
ATTN ISP 4 5 15

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 30, 3:01 PM CDTSevere Thunderstorm WarningLOTCook, DuPage59 min

Nearby

Severe Thunderstorm Warnings in Illinois, 1990Every severe thunderstorm warning 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.