Alert archive / Illinois / Flash Flood Warnings in 1994

Flash Flood Warning 17, NWS St. Louis, MO

April 12, 1994Saint Clair County, Illinois

NWS St. Louis, MO issued this flash flood warning at Apr 12, 1994, 2:56 AM CDT for Saint Clair County, Illinois. It was in force for 5 hr.

The area

The counties it named.

The facts

Issued
Apr 12, 1994, 2:56 AM CDT (07:56 UTC)
Expired
Apr 12, 1994, 8:00 AM CDT
In force
5 hr
Issued by
NWS St. Louis, MO
Area
Whole counties

County Saint Clair County, IL

The radar

The St Louis radar (KLSX), 70 km from the middle of the area, began a volume at 07:58 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Paducah/Barkley, KY (KPAH), launched 00:00Z, 7.9 hours before the alert went out and 189 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, Paducah/Barkley, KY at 00:00Z on 1994-04-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 427 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, Paducah/Barkley, KY at 00:00Z on 1994-04-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 135 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
427 J/kg
Mixed-layer CIN
-66 J/kg
Mixed-layer LCL
1170 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
135 m²/s²
0-3 km storm-relative helicity
180 m²/s²
Significant tornado parameter
0.2
Supercell composite
0.9

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KSTL 120759
FFWSTL
ILC133-163-MOC099-121300-
 
BULLETIN - EBS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
256 AM CDT TUE APR 12 1994
 
THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A
FLASH FLOOD WARNING EFFECTIVE UNTIL  800 AM CDT
FOR PEOPLE IN THE FOLLOWING LOCATIONS...
 
IN SOUTHWEST ILLINOIS
 
   ...MONROE COUNTY...ST CLAIR COUNTY
 
 
IN EAST CENTRAL MISSOURI
 
   ...JEFFERSON COUNTY
 
BETWEN 130 AND 245 AM...A THUNDERSTORM PRODUCED HEAVY RAIN JUST TO THE
SOUTH AND SOUTHEAST OF ST. LOUIS. THIS ADDITIONAL HEAVY RAIN HAS RENEWED
DANGEROUS FLOODING CONDITIONS OVER JEFFERSON COUNTY MISSOURI AND MONROE
AND ST. CLAIR COUNTIES IN ILLINOIS.
 
AT 250 AM...A FLOOD EMERGENCY WAS REPORTED IN THE CITY OF
DESOTO IN JEFFERSON COUNTY.  JOACHIM CREEK WAS AGAIN FLOODING AND SOME
RESIDENCES WERE BEING THREATENED BY THE WATER.
 
 
BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE
THE DANGERS OF FLOODS AND FLASH FLOODS.  IF FLASH FLOODING IS
OBSERVED...ACT QUICKLY.  MOVE UP TO ESCAPE FLOOD WATERS.  DO
NOT STAY IN AREAS SUBJECT TO FLOODING WHEN WATER BEGINS RISING.
 
GKS/TRUETT
 
&

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 11, 8:06 PM CDTFlash Flood WarningLSXPike6 hr
Apr 11, 8:06 PM CDTFlash Flood WarningLSXCalhoun6 hr
Apr 11, 9:26 PM CDTFlash Flood WarningLSXScott5 hr
Apr 12, 1:59 AM CDTFlash Flood WarningLSXCalhoun, Pike6 hr
Apr 12, 1:59 AM CDTFlash Flood WarningLSXGreene, Scott6 hr
Apr 12, 2:56 AM CDTFlash Flood WarningLSXMonroe5 hr

Nearby

Flash Flood Warnings in Illinois, 1994Every flash flood warning in 1994

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; radar from the NEXRAD Level II archive.