Alert archive / Illinois / Severe Thunderstorm Warnings in 1987

Severe Thunderstorm Warning 41, NWS Lincoln, IL

July 6, 1987Boone County, Illinois

NWS Lincoln, IL issued this severe thunderstorm warning at Jul 6, 1987, 3:13 PM CDT for Boone County, Illinois. It was in force for 17 min.

The area

The counties it named.

The facts

Issued
Jul 6, 1987, 3:13 PM CDT (20:13 UTC)
Expired
Jul 6, 1987, 3:30 PM CDT
In force
17 min
Issued by
NWS Lincoln, IL
Area
Whole counties

County Boone 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

Peoria Regional, IL (KPIA), launched 12:00Z, 8.2 hours before the alert went out and 195 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 062013
SVRRFD
ILC007-062030-

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

THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM 
WARNING EFFECTIVE UNTIL 330 PM CDT FOR PEOPLE IN THE FOLLOWING 
COUNTY OF

NORTH CENTRAL ILLINOIS...SOUTHERN BOONE

AT 3 05 PN CDT...RADAR INDCATED A SEVERE THUNDERSTORM APPROCHING
THE WEST SIDE OF ROCKFORD. THE STORM WAS MOVING EAST AT 30 MPH.
TREE DAMAGE WAS REPORTED FROM THIS STORM JUST TO THE SOUTHEAST
OF FREEPORT IN STEPHENSON COUNTY. ALSO MARBLE SIZED HAIL WAS
REPORTED AT PECATONICA.

SOME COMMUNITIES AFFECTED BY THIS SEVERE THUNDERSTORM...
BELVIDERE.

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 THUN6DERSTORMS 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, 2:21 PM CDTSevere Thunderstorm WarningILXStephenson54 min
Jul 6, 2:54 PM CDTSevere Thunderstorm WarningILXWinnebago51 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; the sounding from the Mesonet's radiosonde archive.