Alert archive / Illinois / Severe Thunderstorm Warnings in 1987

Severe Thunderstorm Warning 3, NWS Lincoln, IL

May 11, 1987DeKalb County, Illinois

NWS Lincoln, IL issued this severe thunderstorm warning at May 11, 1987, 5:42 PM CDT for DeKalb County, Illinois. It was in force for 63 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
May 11, 1987, 5:42 PM CDT (22:42 UTC)
Expired
May 11, 1987, 6:45 PM CDT
In force
63 min
Issued by
NWS Lincoln, IL
Area
Whole counties

County DeKalb 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

TimeReportWhereRemark
May 11, 6:02 PM CDTHail 1.75De Kalb, 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, 10.7 hours before the alert went out and 153 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, Peoria Regional, IL at 12:00Z on 1987-05-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 6 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, Peoria Regional, IL at 12:00Z on 1987-05-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 91 square meters per square second.1939Sfc1 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
6 J/kg
Mixed-layer CIN
-104 J/kg
Mixed-layer LCL
1494 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
91 m²/s²
0-3 km storm-relative helicity
101 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KRFD 112257
SVRRFD
ILC037-112345-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE ROCKFORD IL
557 PM CDT MON MAY 11 1987

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

NORTH CENTRAL ILLINOIS...CENTRAL AND SOUTHERN DEKALB

AT 555 PM CDT GOLFBALL SIZE HAIL WAS REPORTED BY SKYWARN SPOTTERS
IN THE CITY OF DEKALB ILLIOIS... ABOUT 25 MILES SOUTHEAST OF
ROCKFORD.  MOVEMENT OF THE STORM  EAST AT 30 MPH.

SOME COMMUNITIES AFFECTED BY THIS SEVERE THUNDERSTORM...
DEKALB... WATERMAN... AND SOMONAUK

IF YOU ARE IN AN AREA THREATENED BY THE STORM... GO TO A REINFORECED
SHELTER.  SEVERE THUNDERSTORMS CAN PRODUCE WINDS OF 60 MPH OR
GREATER... LARGE HAIL... DANGEROUS LIGHTNING AND HEAVY RAIN THAT
CAN QUICKLY FLOOD A LOW LYING AREA.

ATTN: ISP DIST  2                                       PIERCE

The office that day

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

IssuedProductOfficeCountiesLasted
May 11, 5:32 PM CDTSevere Thunderstorm WarningILXLee43 min
May 11, 6:26 PM CDTSevere Thunderstorm WarningILXPeoria, Tazewell49 min

Nearby

Severe Thunderstorm Warnings in Illinois, 1987Every 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.