Alert archive / Illinois / Severe Thunderstorm Warnings in 1992

Severe Thunderstorm Warning 21, NWS St. Louis, MO

April 20, 1992Madison County, Illinois

NWS St. Louis, MO issued this severe thunderstorm warning at Apr 20, 1992, 4:59 PM CDT for Madison County, Illinois. It was in force for 46 min.

The area

The counties it named.

The facts

Issued
Apr 20, 1992, 4:59 PM CDT (21:59 UTC)
Expired
Apr 20, 1992, 5:45 PM CDT
In force
46 min
Issued by
NWS St. Louis, MO
Area
Whole counties

County Madison County, IL

The nearest sounding before it

Paducah/Barkley, KY (KPAH), launched 12:00Z, 10.0 hours before the alert went out and 222 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, Paducah/Barkley, KY at 12:00Z on 1992-04-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 515 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, Paducah/Barkley, KY at 12:00Z on 1992-04-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 244 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
515 J/kg
Mixed-layer CIN
-50 J/kg
Mixed-layer LCL
607 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
244 m²/s²
0-3 km storm-relative helicity
231 m²/s²
Significant tornado parameter
0.5
Supercell composite
3.3

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KSTL 202202
SVRSTL
ILC119-202245-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
459 PM CDT MON APR 20 1992
 
THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  545 PM CDT
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN SOUTHWEST ILLINOIS
 
   ...MADISON COUNTY
 
AT 455 PM...RADAR INDICIATED A LINE OF INTENSE THUNDERSTORMS FROM NEAR
ALTON ILLINOIS THROUGH DOWNTOWN ST LOUIS. THESE STORMS ARE MOVING NORTHE
TABOUT 40 MILES AN HOUR AND WILL MOVE THROUGH ALTON AND EDWARDSVILLE
ILLINOIS BETWEEN 500 AND 545 PM.
 
A TORNADO WATCH IS ALSO IN EFFECT FOR THE WARNED AREA.  REMEMBER
SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE TORNADOES
WITH LITTLE OR NO ADVANCE WARNING.  REMAIN CALM BUT BE ALERT TO
RAPIDLY CHANGING WEATHER CONDITIONS.
 
SHEA

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 19, 7:10 PM CDTSevere Thunderstorm WarningLSXAdams50 min

Nearby

Severe Thunderstorm Warnings in Illinois, 1992Every severe thunderstorm warning in 1992

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.