Alert archive / Illinois / Severe Thunderstorm Warnings in 1987

Severe Thunderstorm Warning 42, NWS St. Louis, MO

July 6, 1987Saint Clair County, Illinois

NWS St. Louis, MO issued this severe thunderstorm warning at Jul 6, 1987, 4:55 PM CDT for Saint Clair County, Illinois. It was in force for 35 min.

The area

The counties it named.

The facts

Issued
Jul 6, 1987, 4:55 PM CDT (21:55 UTC)
Expired
Jul 6, 1987, 5:30 PM CDT
In force
35 min
Issued by
NWS St. Louis, MO
Area
Whole counties

County Saint Clair 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

Salem-Leckrone, IL (KSLO), launched 12:00Z, 9.9 hours before the alert went out and 92 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, Salem-Leckrone, IL at 12:00Z on 1987-07-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2811 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, Salem-Leckrone, IL at 12:00Z on 1987-07-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 151 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
2811 J/kg
Mixed-layer CIN
-34 J/kg
Mixed-layer LCL
724 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
151 m²/s²
0-3 km storm-relative helicity
143 m²/s²
Significant tornado parameter
1.7
Supercell composite
8.8

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KSTL 062155 RRA
SVRSTL
ILC163-062230-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
455 PM CDT MON JUL 6 1987
 
THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM WARNING
EFFECTIVE UNTIL 530 PM CDT FOR THE FOLLOWING COUNTY OF
 
SOUTHWEST ILLINOIS... ST. CLAIR
 
AT 450 PM A SEVERE THUNDERSTORM WAS INDICATED FROM EAST ST LOUIS
ILLINOIS INTO SOUTH ST LOUIS.  WIND DAMAGE WAS REPORTED IN SOUTH
ST LOUIS. THIS STORM WAS MOVING EAST AT 30 MILES AN HOUR AND WILL
MOVE ACROSS ST CLAIR COUNTY. HIGH WINDS AND LARGE HAIL ARE LIKELY.
 
IF YOU ARE CAUGHT OUTSIDE...SEEK SHELTER FROM THE STORM IN A
STRONG BUILDING.  DAMAGING WIND...LARGE HAIL...VERY HEAVY RAIN AND
DEADLY LIGHTNING ARE ALL POSSIBLE IN SEVERE THUNDERSTORMS.  STAY
INSIDE AWAY FROM WINDOWS UNTIL THE STORM HAS PASSED.
 
FELDT

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

Special weather statement, Jul 6, 12:37 PM CDT, 4 hours 18 minutes before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE ST LOUIS MO
1235 PM CDT MON JUL 6 1987

...SEVERE THUNDERSTORM WATCH FOR PARTS OF SOUTHERN ILLINOIS TIL 5 PM...

AT 1230 PM VERY STRONG THUNDERSTORMS WERE SCATTERED 25 TO 75 MILES
NORTH AND EAST OF ST. LOUIS.  A SEVERE THUNDERSTORM WAS 35 MILES
EAST SOUTHEAST OF ST. LOUIS...BETWEEN BREESE AND OKAWVILLE ILLINOIS.
THIS STORM PRODUCED LARGE HAIL JUST EAST OF BELLEVILLE ILLINOIS
AROUND NOON.

OTHER VERY STRONG STORMS WERE BETWEEN WATERLOO AND NEW ATHENS ILLINOIS
ABOUT 25 MILES SOUTHEAST OF ST. LOUIS...AND NEAR THE MISSISSIPPI
RIVER SOUTH OF ELSBERRY MISSOURI...ABOUT 40 MILES NORTHWEST OF
ST. LOUIS.

THE STORMS WERE MOVING EAST AT 25 MPH.

MCCARTHY
Special weather statement, Jul 6, 2:05 PM CDT, 2 hours 50 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE COLUMBIA MO
200 PM CDT MON JUL 6 1987

...STRONG THUNDERSTORMS OVER AUDRAIN AND CALLAWAY COUNTIES...

AT 155 PM CDT STRONG THUNDERSTORMS WERE IN AN AREA 15 MILES WIDE FROM 
MEXICO IN AUDRAIN COUNTY OR 25 MILES NORTHEAST OF COLUMBIA TO EAST OF
KINGDOM CITY OR 25 MILES EAST OF COLUMBIA. THESE STORMS COULD PRODUCE
VERY HEAVY RAIN AND POSSIBLE HAIL AND DANGEROUS LIGHTNING. THE STORMS WERE
MOV.ING EAST AT 25 MILES AN HOUR. WATCH FOR THREATENING WEATHER AND BE 
PREPARED TO MOVE TO SAFETY IF YOU ARE IN THE AREA THREATENED BY THESE
STORMS.

MET
Special weather statement, Jul 6, 2:54 PM CDT, 2 hours 1 minute before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
250 PM CDT MON JUL 6 1987

...STORMS MOVING THROUGH PIKE COUNTY MISSOURI INTO PIKE COUNTY ILLINOIS.

AT 245 PM THUNDERSTORMS PELLTED BOYWLING GREEN MISSOURI WITH SMALL HAIL.
BOWLING GREEN IS ABOUT 60 MILES NORTHWEST OF ST LOUIS.  THESE STORMS
WERE MOVING EAST AT 25 MPH AND WILL PASS THROUGH LOUISIANA MISSOURI
AND PITTSFIELD ILLINOIS BETWEEN 250 PM AND 4 PM.

HAMILTON

The office that day

Everything else NWS St. Louis, MO issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 5, 8:09 PM CDTSevere Thunderstorm WarningLSXCalhoun, Jersey36 min
Jul 6, 11:20 AM CDTSevere Thunderstorm WarningLSXSaint Clair55 min
Jul 6, 12:00 PM CDTSevere Thunderstorm WarningLSXClinton, Saint Clair, Washington60 min
Jul 6, 1:05 PM CDTSevere Thunderstorm WarningLSXJefferson, Marion, Washington40 min
Jul 6, 3:10 PM CDTSevere Thunderstorm WarningLSXCalhoun, Pike50 min
Jul 6, 3:24 PM CDTSevere Thunderstorm WarningLSXGreene39 min
Jul 6, 4:24 PM CDTSevere Thunderstorm WarningLSXCalhoun, Jersey, Madison51 min
Jul 6, 5:26 PM CDTSevere Thunderstorm WarningLSXFayette64 min
Jul 6, 5:52 PM CDTSevere Thunderstorm WarningLSXEffingham53 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.