Alert archive / Illinois / Flash Flood Warnings in 1986

Flash Flood Warning 2, NWS Lincoln, IL

September 20, 1986Sangamon County, Illinois

NWS Lincoln, IL issued this flash flood warning at Sep 20, 1986, 2:46 AM CDT for Sangamon County, Illinois. It was in force for 4 hr.

The area

The counties it named.

The facts

Issued
Sep 20, 1986, 2:46 AM CDT (07:46 UTC)
Expired
Sep 20, 1986, 7:00 AM CDT
In force
4 hr
Issued by
NWS Lincoln, IL
Area
Whole counties

County Sangamon 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, 7.8 hours before the alert went out and 102 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 1986-09-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1948 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 1986-09-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 316 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
1948 J/kg
Mixed-layer CIN
-53 J/kg
Mixed-layer LCL
878 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
316 m²/s²
0-3 km storm-relative helicity
450 m²/s²
Significant tornado parameter
4.6
Supercell composite
34.0

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KSPI 200746
FFWSPI
ILC167-201200-

BULLETIN - IMMEDIATE BROADCAST REQUESTED/EBS ACTIVATION REQUESTED 
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SPRINGFIELD IL
246 AM CDT SAT SEP 20 1986

THE NATIONAL WEATHER SERVICE HAS ISSUED A FLASH FLOOD WARNING 
EFFECTIVE UNTIL 700 AM CDT FOR PEOPLE IN THE FOLLOWING COUNTY OF

CENTRAL ILLINOIS...SANGAMON

SPRINGFIELD CITY POLICE AND THE SANGAMON COUNTY SHERIFFS DEPARTMENT
HAS REPORTED EXTENSIVE FLOODING IN THE CITY OF SPRINGFIELD OF STREET
S AMD VIADUCTS. FLOODING WAS MAINLY IN THE CITY...BUT ALSO SOME
VIADUCT FLOODING IN OUTLYING AREAS. OVER THREE INCHES OF RAIN HAS
BEEN RECORDED AT CAPITAL AIRPORT SINCE MIDNIGHT.

THUNDERSTORMS WITH HEAVY RAIN ARE EXPECTED TO CONTINUE FOR THE NEXT
SEVERAL HOURS. AMOUNTS UP TO FIVE INCHES ARE POSSIBLE

FLOWING WATERS AND DARKNESS CAN BE A KILLING COMBINATION, DO NOT
ATTEMPT TO DRIVE OR WALK THROUGH THESE AREAS. LOCALLY DANGEROUS
CONDITIONS ARE POSSIBLE UNTIL AT LEAST 7 AM.

 ATTN ISP DIST...9
 FS

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 19, 9:02 PM CDTSevere Thunderstorm WarningILXMcLean58 min
Sep 20, 12:33 AM CDTFlash Flood WarningILXDeWitt, Logan5 hr

Nearby

Flash Flood Warnings in Illinois, 1986Every flash flood warning in 1986

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.