Alert archive / Illinois / Flash Flood Warnings in 1986

Flash Flood Warning 5, NWS St. Louis, MO

September 18, 1986Monroe County, Saint Clair County, Illinois

NWS St. Louis, MO issued this flash flood warning at Sep 18, 1986, 3:23 AM CDT for Monroe County, Saint Clair County, Illinois. It was in force for 3 hr.

The area

The counties it named.

The facts

Issued
Sep 18, 1986, 3:23 AM CDT (08:23 UTC)
Expired
Sep 18, 1986, 6:20 AM CDT
In force
3 hr
Issued by
NWS St. Louis, MO
Area
Whole counties

Counties Monroe County, IL, Saint Clair 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

Salem-Leckrone, IL (KSLO), launched 00:00Z, 8.4 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, Salem-Leckrone, IL at 00:00Z on 1986-09-18Temperature 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, Salem-Leckrone, IL at 00:00Z on 1986-09-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 167 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
NaN m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
167 m²/s²
0-3 km storm-relative helicity
190 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KSTL 180823
FFWSTL
ILC133-163-181120-
 
BULLETIN - EBS ACTIVATION AND IMMEDIATE BROADCAST REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
323 AM CDT THU SEP 18 1986
 
THE NATIONAL WEATHER SERVICE HAS ISSUED A FLASH FLOOD WARNING
EFFECTIVE UNTIL 620 AM CDT FOR THE FOLLOWING COUNTIES OF
 
SOUTHWEST ILLINOIS... MONROE... SOUTH ST. CLAIR
                                                                         
SHOWERS AND THUNDERSTORMS HAVE OCCURRED SINCE 9 PM WEDNESDAY EVENING  
AND WILL LIKELY CONTINUE FOR THE NEXT FEW HOURS. AMOUNTS IN EXCESS OF  
3 TO 5 INCHES ARE LIKELY. THIS INCLUDES THE COMMUNITY OF WATERLOO AND  
THE LOWER KASKASKIA RIVER AND ITS TRIBUTARIES. THIS IS AN UNUSUALLY 
DANGEROUS SITUATION. RADAR INDICATES VERY HEAVY RAINFALL WILL PERSIST  
IN THIS AREA UNTIL ABOUT SUNRISE. DO NOT DRIVE THROUGH FLOWING WATER. 
                       
 
FLASH FLOODING IS IMMINENT IN THIS AREA.  IF YOU LIVE
ALONG THESE RIVERS AND STREAMS...YOU SHOULD GO TO SAFETY IMMEDIATELY.
                                                                         
 
PEDIGO

The office that day

Everything else NWS St. Louis, MO issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 18, 7:04 AM CDTFlash Flood WarningLSXMonroe3 hr
Sep 18, 9:45 AM CDTFlash Flood WarningLSXPerry, Randolph3 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.