Alert archive / Illinois / Severe Thunderstorm Warnings in 1987

Severe Thunderstorm Warning 1, NWS Lincoln, IL

April 11, 1987DeWitt County, Piatt County, Illinois

NWS Lincoln, IL issued this severe thunderstorm warning at Apr 11, 1987, 4:05 PM CDT for DeWitt County, Piatt County, Illinois. It was in force for 55 min. 2 reports came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Apr 11, 1987, 4:05 PM CDT (21:05 UTC)
Expired
Apr 11, 1987, 5:00 PM CDT
In force
55 min
Issued by
NWS Lincoln, IL
Area
Whole counties

Counties DeWitt County, IL, Piatt County, IL

The radar

The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.

What was reported inside it

TimeReportWhereRemark
Apr 11, 4:28 PM CDTTornado F1De Witt, IL
Apr 11, 4:56 PM CDTTornado F1Piatt, IL

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in. Storm Data before 1996 records only tornadoes, thunderstorm wind and hail.

The nearest sounding before it

Peoria Regional, IL (KPIA), launched 12:00Z, 9.1 hours before the alert went out and 97 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 12:00Z on 1987-04-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 12:00Z on 1987-04-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 79 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1952 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
79 m²/s²
0-3 km storm-relative helicity
116 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 112110 COR
SVRSPI
ILC039-147-112200-

BULLETIN - IMMEDIATE BROADCAST REQUESTED/EBS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SPRINGFIELD IL
405 PM CDT SAT APR 11 1987

THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM
WARNING EFFECTIVE UNTIL 500 PM CDT FOR PEOPLE IN THE FOLLOWING
COUNTIES OF

CENTRAL ILLINOIS...DE-WITT AND NORTHERN PIATT

AT 3 56 PM DE WITT COUNTY ESDA REPORTED THREE QUARTER INCH HAIL
IN CLINTON ILLINOIS. RADAR INDICATED A STRONG THUNDERSTORM IN THE
SAME AREA. THE THUNDERSTORM WAS MOVING EAST AT 25 MILES AN HOUR.

REMEMBER...A SEVERE THUNDERSTORM PRODUCES DAMAGING WINDS IN EXCESS
OF 60 MPH...LARGE HAIL...DEADLY LIGHTNING AND HEAVY RAINS THAT CAN
QUICKLY FLOOD A LOW LYING AREA.
THESE STORMS CAN AND OCCASIONALLY DO PRODUCE A TORNADO WITH LITTLE
OR NO ADVANCE WARNING...SO BE ON THE LOOKOUT AND BE PREPARED TO MOVE
TO A PLACE OF SAFETY IF ONE IS SPOTTED.

IF THREATENING WEATHER APPROACHES^...YOU SHOULD GO TO A SAFE PLACE.
ASK THE NEAREST LAW ENFORCEMENT AGENCY TO RELAY YOUR REPORT OF
SEVERE WEATHER TO THE NATIONAL WEATHER SERVICE.

 ATTN ISP DIST...6 AND 10
 GOODSELL

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, Apr 11, 3:07 PM CDT, 58 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PEORIA IL
305 PM CDT SAT APR 11 1987

A LINE OF HEAVY THUNDERSTORMS HAD DEVELOPED OVER NORTH CENTRAL
ILLINOIS FROM MOLINE EXTENDING SOUTHEAST TO CANTON...AND WERE
MOVING NORTHEAST AT 35 MPH.

A FEW OF THESE THUNDERSTORMS COULD BE ACCOMPANIED WITH BRIEF PEROIDS
OF HEAVY DOWNPOURS...SOME SMALL HAIL AND STRONG GUSTY SURFACE WINDS.

AT 230 PM CDT SMALL HAIL WAS REPORTED IN THE GALESBURG AREA.

ATTN4 ISP 6 8 17

STUMETZ

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 11, 3:51 PM CDTTornado WarningILXPeoria, Woodford69 min
Apr 11, 4:27 PM CDTTornado WarningILXDeWitt, Logan33 min
Apr 11, 4:42 PM CDTTornado WarningILXMacon, Piatt33 min
Apr 11, 4:42 PM CDTTornado WarningILXChampaign33 min
Apr 11, 5:10 PM CDTTornado WarningILXChampaign, Piatt35 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.