Alert archive / Illinois / Severe Thunderstorm Warnings in 1987

Severe Thunderstorm Warning 62, NWS St. Louis, MO

August 20, 1987Adams County, Illinois

NWS St. Louis, MO issued this severe thunderstorm warning at Aug 20, 1987, 8:18 PM CDT for Adams County, Illinois. It was in force for 27 min.

The area

The counties it named.

The facts

Issued
Aug 20, 1987, 8:18 PM CDT (01:18 UTC)
Expired
Aug 20, 1987, 8:45 PM CDT
In force
27 min
Issued by
NWS St. Louis, MO
Area
Whole counties

County Adams 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 00:00Z, 1.3 hours before the alert went out and 154 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 00:00Z on 1987-08-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1095 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 00:00Z on 1987-08-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 92 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
1095 J/kg
Mixed-layer CIN
-45 J/kg
Mixed-layer LCL
1543 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
92 m²/s²
0-3 km storm-relative helicity
231 m²/s²
Significant tornado parameter
0.4
Supercell composite
6.0

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KSTL 210117
SVRSTL
ILC001-210145-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
818 PM CDT THU AUG 20 1987
 
THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM WARNING
EFFECTIVE UNTIL 845 PM CDT FOR THE FOLLOWING COUNTY OF
 
WEST CENTRAL ILLINOIS... SOUTHWESTERN ADAMS

AT 815 PM CDT RADAR INDICATEED A SEVERE THUDNERSTORM WAS MOVING INTO
SOUTHWEST ADAMS COUNTY INCLUDING THE QUINCY AREA.
 
PROTECT YOURSELF FROM DAMAGING WINDS...LARGE HAIL AND LIGHTNING
BY STAYING IN A BUILDING...AWAY FROM WINDOWS.  DO NOT USE THE
TELEPHONE OR ELECTRICAL APPLIANCES...EXCEPT IN EMERGENCIES.
 
HEAVY RAINS REDUCE VISIBILITY AND QUICKLY FLOOD ROADES AND LOW
LYING AREAS.  MOTORISTS SHOULD BE ALERT.  DO NOT WALK OR DRIVE
THROUGH FLOODED AREAS.  STAY AWAY FROM STORM DRAINS.
 
SLAUGHTER

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

In the hours before

Local storm report, Aug 20, 7:39 PM CDT, 39 minutes before
STORM REPORT
NATIONAL WEATHER SERVICE ST LOUIS MO
735 PM CDT THU AUG 20 1987

THE FOLLOWING REPORTS WERE RECIEVED BY THE NATIONAL WEATHER
SERVICE...ST LOUIS MO.

720 PM CDT...70 MPH WIND 2 MILES NORTH O&F KIRKSVILLE...KTVO TV...
LIGHTNING..HEAVY RAIN..NO HAIL.

733 PM CDT...GOLF BALL SIZE HAIL AT KIRX RADIO STATION IN KIRKSVILLE
MISSOURI.

SLAUGHTER
Special weather statement, Aug 20, 7:42 PM CDT, 36 minutes before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE ST LOUIS MO
737 PM CDT THU AUG 20 1987

AT 730 PM CDT...NUMEROUS STRONG THUNDERSTORMS...SOME WITH HEAVY RAIN
AND LARGE HAIL...CONTINUED OVER SOUTHEAST IOWA NORTHEAST MISSOURI AND
SCATTERED RAINSHOWERS OVER WEST ILLINOIS.

A STRONG THUNDERSTORM WITH HEAVY RAIN AND LARGE HAIL CONTINUED OVER
NORTHEAST MISSOURI 5 MILES NORTH OF KIRKSVILLE MISSOURI.

OTHER STRONG STORMS WAS LOCATED 5 MILES EAST OF EDINA MISSOURI.

THIS ENTIRE AREA OF SHOWERS AND STORMS EXTENDED FROM KIRKSVILLE
MISSOURI TO 20 MILES WEST OF PEORIA ILLINOIS.

MOVEMENT OF THE SHOWERS AND STORMS WAS SOUTHEAST AT 35 MILES AN HOUR.

REMEMBER...STRONG (WINDS AND SOME HAIL MAY ACCOMPANY THESE STORMS.
DYE
Special weather statement, Aug 20, 8:11 PM CDT, 7 minutes before
SPECIAL WEATHER STATEMENT FOR NORTHEAST MISSOURI
NATIONAL WEATHER SERVICE ST LOUIS MO
805 PM CDT THU AUG 20 1987

NUMEROUS TREES AND POWER LINES WERE REPORTED DOWN IN ADAIR...MOSTLY
IN THE KIRKSVILLE AREAA.  TRAVEL IN ADAIR COUNTY IS DANGEROUS AT THE
PRESENT TIME.  SOME BRIDGES WERE REPORTED UNDER WATER FROM FLASH
FLOODING FROM THEST STORMS.

THE FLASH FLOODING WILL REMAIN A THREAT UNTIL ABOUT 10 PM THIS EVENING.

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.