Alert archive / Illinois / Severe Thunderstorm Warnings in 1987

Severe Thunderstorm Warning 46, NWS Lincoln, IL

July 9, 1987Macon County, Illinois

NWS Lincoln, IL issued this severe thunderstorm warning at Jul 9, 1987, 11:25 AM CDT for Macon County, Illinois. It was in force for 36 min. 1 report 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
Jul 9, 1987, 11:25 AM CDT (16:25 UTC)
Expired
Jul 9, 1987, 12:01 PM CDT
In force
36 min
Issued by
NWS Lincoln, IL
Area
Whole counties

County Macon 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
Jul 9, 12:00 PM CDTThunderstorm Wind 0Macon, 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, 4.4 hours before the alert went out and 105 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 1987-07-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2378 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 12:00Z on 1987-07-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -21 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
2378 J/kg
Mixed-layer CIN
-44 J/kg
Mixed-layer LCL
727 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
-21 m²/s²
0-3 km storm-relative helicity
50 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 091625
SVRSPI
ILC115-091715-

BULLETIN - IMMEDIATE BROADCAST REQUESTED/EBS ACTIVATION REQUESTED 
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SPRINGFIELD IL
1125 AM CDT THU JUL 9 1987

THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM 
WARNING EFFECTIVE UNTIL 1215 PM CDT FOR PEOPLE IN THE FOLLOWING 
COUNTY OF

CENTRAL ILLINOIS...MACON

AT 11 20 AM CDT MACON COUNTY EMERGENCY SERVICES AGENCY REPORTED
TREES UPROOTED AND HIGH WINDS NEAR BLUE MOUND ILLINOIS IN SOUTHERN
MACON COUNTY. BLUE MOUND IS 15 MILES SOUTH OF DECATUR ILLINOIS.

THE AREA OF THUNDERSTORMS WERE MOVING EAST AT 20 MPH.

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.

THIS SLOW MOVING THUNDERSTORM MAY CAUSE FLOODING OF SMALL STREAMS
AND UNDERPASSES.

INTENSE LIGHTNING IS REPORTED WITH THIS STORM.  IF OUTDOORS...
STAY AWAY FROM HIGH OBJECTS.  MOVE INDOOR IF POSSIBLE.  WHEN
INDOORS...STAY AWAY FROM WINDOWS AND DOORS AND AVOID USING
TELEPHONES AND ELECTRICAL EQUIPMENT.

THIS IS A DANGEROUS STORM. TAKE COVER IMMEDIATELY.

 ATTN ISP DIST...10
 HILLIARD

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 9, 9:45 AM CDT, 1 hour 40 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SPRINGFIELD IL
9 40 AM CDT THU JUL 9 1987

...STRONG THUNDERSTORMS IN CENTRAL ILLINOIS...
AT 9 35 AM CDT WEATHER SERVICE RADARS SHOWS VERY STRONG THUNDERSTORMS
IN A 40 MILE WIDE BAND 20 MILES EITHER SIDE OF A LINE FROM ALTON ILLINOIS
TO JUST NORTHEAST OF CLINTON ILLINOIS IN DE-WITT COUNTY.

THE STRONGEST THUNDERSTORMS WERE IN CHRISTIAN COUNTY JUST EAST OF
TAYLORVILLE ILLINOIS AND SOUTHERN MACON COrUNTY SOUTH OF DECATUR ILLINOIS.
THE SHOWERS AND THUNDERSTORMS WERE MOVING EAST AT 20 MPH

THESE THUNDERSTORMS MAY PRODUCE VERY HEAVY RAINFALL...BRIEF STRONG AND
GUSTY WINDS...HAIL AND DANGEROUS LIGHTNING.

HILLIARD

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.