Alert archive / Illinois / Severe Thunderstorm Warnings in 1991

Severe Thunderstorm Warning 21, NWS Lincoln, IL

April 28, 1991Morgan County, Illinois

NWS Lincoln, IL issued this severe thunderstorm warning at Apr 28, 1991, 3:42 AM CDT for Morgan County, Illinois. It was in force for 48 min.

The area

The counties it named.

The facts

Issued
Apr 28, 1991, 3:42 AM CDT (08:42 UTC)
Expired
Apr 28, 1991, 4:30 AM CDT
In force
48 min
Issued by
NWS Lincoln, IL
Area
Whole counties

County Morgan County, IL

The nearest sounding before it

Paducah/Barkley, KY (KPAH), launched 00:00Z, 8.7 hours before the alert went out and 322 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 00:00Z on 1991-04-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 121 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 00:00Z on 1991-04-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 100 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
121 J/kg
Mixed-layer CIN
-340 J/kg
Mixed-layer LCL
934 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
100 m²/s²
0-3 km storm-relative helicity
102 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 KSPI 280842
SVRSPI
ILC137-280930-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING 
NATIONAL WEATHER SERVICE SPRINGFIELD IL
342 AM CDT SUN APR 28 1991

THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM 
WARNING EFFECTIVE UNTIL 430 AM CDT FOR PEOPLE IN THE FOLLOWING 
COUNTY

   IN THE CENTRAL PART OF ILLINOIS
      SOUTHERN MORGAN

AT 335 AM...RADAR INDICATED A SEVERE THUNDERSTORM 35 MILES
SOUTHWEST OF SPRINGFIELD ILLINOIS...BETWEEN WAVERLEY AND
MURRAYVILLE.  THE STORM WAS MOVING NORTHEAST AT 35 MPH.

STRONG WINDS HAVE BEEN REPORTED WITH THIS STORM AS IT PASSED
THROUGH GREENE COUNTY.

IF YOU ARE IN AN AREA THREATENED BY THE STORM..GO TO A REINFORCED
SHELTER AND PREPARE FOR DAMAGING WIND...LARGE HAIL...VERY HEAVY
RAIN AND DANGEROUS LIGHTNING.

 ATTN ISP DIST... 9
 DB

The office that day

Everything else NWS Lincoln, IL issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 28, 5:12 AM CDTSevere Thunderstorm WarningILXSangamon33 min
Apr 28, 5:31 AM CDTSevere Thunderstorm WarningILXMacon59 min
Apr 28, 6:12 AM CDTSevere Thunderstorm WarningILXDeWitt48 min
Apr 28, 6:34 AM CDTSevere Thunderstorm WarningILXPiatt41 min

Nearby

Severe Thunderstorm Warnings in Illinois, 1991Every severe thunderstorm warning in 1991

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.