Alert archive / Illinois / Severe Thunderstorm Warnings in 1987

Severe Thunderstorm Warning 39, NWS Lincoln, IL

July 6, 1987Stephenson County, Illinois

NWS Lincoln, IL issued this severe thunderstorm warning at Jul 6, 1987, 2:21 PM CDT for Stephenson County, Illinois. It was in force for 54 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
Jul 6, 1987, 2:21 PM CDT (19:21 UTC)
Expired
Jul 6, 1987, 3:15 PM CDT
In force
54 min
Issued by
NWS Lincoln, IL
Area
Whole counties

County Stephenson 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
Jul 6, 2:30 PM CDTThunderstorm Wind 0Stephenson, 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, 7.4 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, Peoria Regional, IL at 12:00Z on 1987-07-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 1987-07-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 51 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
NaN m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
51 m²/s²
0-3 km storm-relative helicity
86 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 061921
SVRRFD
ILC177-062015-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE ROCKFORD IL
221 PM CDT MON JUL 6 1987

THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM 
WARNING EFFECTIVE UNTIL 315 PM CDT FOR PEOPLE IN THE FOLLOWING 
COUNTY OF

NORTHWEST ILLINOIS...SOUTHERN STEPHENSON

AT 2 15 PM CDT...RADAR INDICATED A SEVERE THUNDERSTORM IN SOUTHWEST
STEPHENSON COUNTY NEAR TO TOWN OF LORAN. THIS IS JUST SOUTHWEST
OF PEARL CITY...WHICH IS ABOUT 40 MILES WEST OF ROCKFORD.
THE STORM WAS MOVING TO THE EAST AT 25 MPH.

SOME COMMUNITIES AFFECTED BY THIS SEVERE THUNDERSTORM...
PEARL CITY...FREEPORT...GERMAN VALLEY.

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.

REMEMBER... SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE
A TORNADO WITH LITTLE OR NO ADVANCE WARNING SO BE ALERT!

ATTN: ISP DIST  16.                                     SANDERS

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 6, 12:21 AM CDTTornado WarningILXClark, Cumberland24 min
Jul 6, 1:52 PM CDTSevere Thunderstorm WarningILXCarroll53 min
Jul 6, 2:54 PM CDTSevere Thunderstorm WarningILXWinnebago51 min
Jul 6, 3:13 PM CDTSevere Thunderstorm WarningILXBoone17 min
Jul 6, 4:37 PM CDTSevere Thunderstorm WarningILXMacoupin53 min
Jul 6, 4:45 PM CDTSevere Thunderstorm WarningILXMontgomery60 min
Jul 6, 5:05 PM CDTTornado WarningILXKnox, Peoria55 min
Jul 6, 6:55 PM CDTSevere Thunderstorm WarningILXColes, Edgar45 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.