Alert archive / Illinois / Severe Thunderstorm Warnings in 1987

Severe Thunderstorm Warning 52, NWS St. Louis, MO

July 30, 1987Randolph County, Illinois; Sainte Genevieve County, Missouri

NWS St. Louis, MO issued this severe thunderstorm warning at Jul 30, 1987, 4:02 PM CDT for Randolph County, Illinois; Sainte Genevieve County, Missouri. It was in force for 28 min.

The area

The counties it named.

The facts

Issued
Jul 30, 1987, 4:02 PM CDT (21:02 UTC)
Expired
Jul 30, 1987, 4:30 PM CDT
In force
28 min
Issued by
NWS St. Louis, MO
Area
Whole counties

Counties Randolph County, IL, Sainte Genevieve County, MO

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, 9.0 hours before the alert went out and 123 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 1987-07-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2921 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 1987-07-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 54 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
2921 J/kg
Mixed-layer CIN
-28 J/kg
Mixed-layer LCL
720 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
54 m²/s²
0-3 km storm-relative helicity
85 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.5

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KSTL 302053
SVRSTL
ILC157-MOC186-302130-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
402 PM CDT THU JUL 30 1987
 
THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM WARNING
EFFECTIVE UNTIL 430 PM CDT FOR THE FOLLOWING COUNTIES OF
 
SOUTHWEST ILLINOIS... WESTERN RANDOLPH
 
SOUTHEAST MISSOURI... EASTERN STE. GENEVIEVE
 
AT 345 PM A SEVERE THUNDERSTORM PRODUCED DAMAGING WINDS NEAR
PRAIRE DU ROCHER...ABOUT 50 MILES SOUTH OF ST LOUIS IN SOUTHWEST
ILLINOIS.
 
THE STORMS WERE MOVING TO THE SOUTH AT 25 MPH.
 
SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 55 MPH
...LARGE HAIL...DEADLY LIGHTNING AND VERY HEAVY RAIN.  FOR YOUR
PROTECTION GO TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR
HOME OR BUSINESS.
 
HAMILTON/BROWNING

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 30, 1:19 PM CDT, 2 hours 43 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
110  M CDT THU JUL 30 1987

...HEAT INDEX ON THE RISE...

HOT WEATHER CONTINUES OVER ALL OF MISSOURI THIS AFTERNOON.  THE
TEMPERATURE AT 1 PM WAS NEAR 100 IN THE EXTREME NORTHWEST.  THE
TEMPERATURE HAD REACHED 98 IN DOWNTOWN KANSAS CITY.  TEMPERATURES IN
EASTERN MISSOURI WERE IN THE MID 90S.  HOWEVER...THE HEAT INDEX
HAD REACHED 108 AT ST LOUIS INTERNATIONAL AIRPORT AND 109 AT SPIRIT
OF ST LOUIS AIRPORT.  THE HEAT INDEX WAS OVER 100 EVERYWHERE IN THE
STATE.

TEMPERATURES WILL CLIMB TO AROUND 100 IN KANSAS CITY AND TO 97 OR 98
IN ST LOUIS THIS AFTERNOON.  THE HIGHER RELATIVE HUMIDITY IN ST LOUIS
WILL GIVE ST LOUIS A HEAT INDEX OF NEAR 110.  ISOLATED THUNDERSTORMS
WILL BE OVER PORTIONS OF EASTERN MISSOURI THIS AFTERNOON BUT WILL OFFER
LITTLE IF ANY RELIEF.
PERSONS SHOULD AVOID PROLONGED PHYSICAL ACTIVITY DURING THIS PERIOD
OF EXCESSIVE HEAT.  PERSONS ADVERSELY AFFECTED BY THE HEAT
SHOULD REMAIN INSIDE AN AIR CONDITIONED BUILDING THIS AFTERNOON.
BE SURE TO CHECK ON ELDERLY OR INFIRM NEIGHBORS.

TUCKER
Special weather statement, Jul 30, 3:51 PM CDT, 11 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
345 PM CDT THU JUL 30 1987

...VERY STRONG THUNDERSTORMS MOVING THROUGH RANDOLPH COUNTY ILLINOIS...

AT 340 PM CDT THUNDERSTORMS WERE LOCATED NEAR REDBUD AND EVANSVILLE
ILLINOIS OR ABOUT 40 MILES SOUTH SOUTHEAST OF ST LOUIS.  THESE STORMS
WERE MOVING SOUTH AT 30 MPH AND WILL MOVE THROUGH WESTERN RANDOLPH
COUNTY ILLINOIS AND STE GENEVIEVE COUNTY MISOURI BETWEEN 345 AND 445
PM.  PE}RSONS IN AND NEAR THE TOWNS OF EVANSVILLE..SPARTA..STEELVILLE AND
CHESTER IN ILLINOIS..ALSO IN MISSOURI THE TOWNS OF STE GENEVIEVE AND
ST MARYS CAN ALL EXPECT VERY HEAVY RAINS WITH AND SOME HAIL AND STRONG
GUSTY WINDS.

HAMILTON

Nearby

Severe Thunderstorm Warnings in Illinois, 1987Severe Thunderstorm Warnings in Missouri, 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.