Alert archive / Illinois / Tornado Warnings in 1987

Tornado Warning 25, NWS Lincoln, IL

August 21, 1987Woodford County, Illinois

NWS Lincoln, IL issued this tornado warning at Aug 21, 1987, 6:24 AM CDT for Woodford County, Illinois. It was in force for 31 min.

The area

The counties it named.

The facts

Issued
Aug 21, 1987, 6:24 AM CDT (11:24 UTC)
Expired
Aug 21, 1987, 6:55 AM CDT
In force
31 min
Issued by
NWS Lincoln, IL
Area
Whole counties

County Woodford 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

Peoria Regional, IL (KPIA), launched 00:00Z, 11.4 hours before the alert went out and 35 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 00:00Z on 1987-08-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1095 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, Peoria Regional, IL at 00:00Z on 1987-08-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 92 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
1095 J/kg
Mixed-layer CIN
-45 J/kg
Mixed-layer LCL
1543 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
92 m²/s²
0-3 km storm-relative helicity
231 m²/s²
Significant tornado parameter
0.4
Supercell composite
6.0

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KPIA 211124 RRA
TORPIA
ILC203-211230-

BULLETIN - IMMEDIATE BROADCAST REQUESTED/EBS ACTIVATION REQUESTED 
TORNADO WARNING
NATIONAL WEATHER SERVICE PEORIA IL
624 AM CDT FRI AUG 21 1987

THE NATIONAL WEATHER SERVICE HAS ISSUED A TORNADO WARNING 
EFFECTIVE UNTIL 730 AM CDT FOR PEOPLE IN THE FOLLOWING COUNTY OF

CENTRAL ILLINOIS...WOODFORD

AT 620 AM CDT SEVERAL PILOT REPORTS AND SURFACE REPORTS OF FUNNEL
CLOUDS OVER NORTHWESTERN WOODFORD COUNTY.  AT 600 AM A POSSIBLE
TORNADO HIT PRINCEVILLE IL...20 MILES NORTHWEST OF PEORIA.

THE FUNNEL CLOUDS ARE ASSOCIATED WITH A THUNDERSTORM MOVING
RAPIDLY TO THE SOUTHEAST AT APPROXIMATELY 50 MPH.

IF YOU ARE IN THE PATH OF THIS TORNADO...GO TO A BASEMENT SHELTER
IF AVAILABLE...OTHERWISE TO A CENTRAL INTERIOR ROOM ON THE LOWEST
FLOOR.  ABANDON CARS AND MOBILE HOMES FOR A REINFORCED BUILDING.

THIS IS A DANGEROUS STORM.  TAKE COVER IMMEDIATELY.

ATTN ISP DIST 8

LAST/MACH

What forecasters said that day

The local office's own words before this tornado 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, Aug 21, 3:00 AM CDT, 3 hours 24 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PEORIA IL
300 AM CDT FRI AUG 21 1987

     ...STRONG THUNDERSTORMS MOVING INTO STARK COUNTY...

AT 255 AM CDT WEATHER SERVICE RADAR INDICATED AN AREA OF SHOWERS
AND STRONG THUNDERSTORMS EXTENDING NORTH OF A LINE FROM BLOOMINGTON
TO GALESBURG IL TO 20 MILES NORTH OF BURLINGTON IA.  THE STRONGEST
THUNDERSTORMS WERE LOCATED IN SOUTHEAST HENRY COUNTY AND NEAR THE
CITY OF MOLINE.

THE STORM IN HENRY COUNTY WILL BE MOVING INTO STARK COUNTY BY 330 AM
AND WILL BE AFFECTING THE TOWNS OF TOULON AND WYOMING...30 MILES NORTH
OF PEORIA.

HEAVY RAIN...DANGEROUS LIGHTNING...AND STRONG GUSTY WINDS CAN BE
EXPECTED WITH THESE STORMS AS THEY MOVE THROUGH THE AREA.  THE RAIN
AREA WAS MOVING TO THE SOUTHEAST AT 30 MPH.

JK LAST

ATTN ISP DIST...8
Special weather statement, Aug 21, 3:40 AM CDT, 2 hours 44 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PEORIA IL
340 AM CDT FRI AUG 21 1987

    ...STRONG THUNDERSTORMS NORTH AND WEST OF PEORIA...

AT 335 AM CDT NATIONAL WEATHER SERVICE RADAR INDICATED A LARGE AREA
OF SHOWERS AND STRONG THUNDERSTORMS NORTH OF A LINE FROM CHAMPAIGN
TO PEORIA IL TO 15 MILES EAST OF BURLINGTON IA.  THE STRONGEST
THUNDERSTORMS WERE LOCATED IN NORTHERN KNOX COUNTY..10 MILES EAST
OF GALESBURG...AND IN SOUTHERN BUREAU COUNTY..NEAR TISKILWA WHICH
IS 45 MILES NORTH OF PEORIA.

THESE THUNDERSTORMS ARE MOVING TO THE SOUTHEAST AT 35 MPH AND WILL
BE AFFECTING THE COUNTIES OF PEORIA...STARK...AND BUREAU THROUGHOUT
THE EARLY MORNING HOURS.

HEAVY RAIN...DANGEROUS LIGHTNING...AND STRONG GUSTY WINDS CAN BE
EXPECTED WITH THESE STORMS AS THEY MOVE THROUGH THE AREA.

JK LAST

ATTN ISP DIST...7...8...17
Special weather statement, Aug 21, 4:40 AM CDT, 1 hour 44 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PEORIA IL
435 AM CDT FRI AUG 21 1987

          ...STRONG THUNDERSTORM OVER PEORIA...

AT 425 AM CDT NATIONAL WEATHER SERVICE RADAR INDICATED A VERY STRONG
THUNDERSTORM OVER PEORIA IL.  A PEAK WIND GUST OF 45 MPH WAS RECORDED
HERE AT THE GREATER PEORIA AIRPORT AT 417 AM AND 0.40 INCHES OF RAIN
FELL IN 15 MINUTES.  THIS THUNDERSTORM IS ENTERING NORTHERN TAZEWELL
COUNTY AND WILL BE AFFECTING THE TOWNS OF PEKIN...MORTON AND MACKINAW.

ANOTHER STRONG THUNDERSTORM WAS OVER WESTERN BUREAU COUNTY.

THE THUNDERSTORMS ARE MOVING TO THE SOUTHEAST AT 35 MPH.

HEAVY RAIN...DANGEROUS LIGHTNING...AND STRONG GUSTY WINDS CAN BE
EXPECTED WITH THESE STORM?S AS THEY MOVE THROUGH THE AREA.

JK LAST

ATTN ISP DIST...7...8...17
Special weather statement, Aug 21, 6:01 AM CDT, 23 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PEORIA IL
600 AM CDT FRI AUG 21 1987

...SEVERE THUNDERSTORM WARNING FOR KNOX...STARK...AND BUREAU COUNTIES
CANCELLED...

AT 550 AM CDT WEATHER SERVICE RADAR INDICATED A VERY STRONG
THUNDERSTORM EXTENDING FROM SPRING VALLEY...45 MILES NORTHEAST OF
PEORIA...TO PRINCEVILLE...15 MILES NORTHWEST OF PEORIA.  THE STORM
HAD MOVED OUT OF KNOX...STARK AND BUREAU COUNTIES AND HAD WEAKENED.

THIS STORM WILL BE AFFECTING NORTHERN PEORIA...MARSHALL AND PUTNAM
COUNTIES UNTIL 630 AM CDT.  HEAVY RAIN...DANGEROUS LIGHTNING AND
STRONG GUSTY WINDS CAN BE EXPECTED WITH THIS STORM AS IT MOVES
SOUTHEAST AT 50 MPH.

JKLAST

ATTN ISP DIST... 8 AND 17

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 21, 5:34 AM CDTSevere Thunderstorm WarningILXBureau, Knox, Stark26 min

Nearby

Tornado Warnings in Illinois, 1987Every tornado warning in 1987Tornadoes 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.