Alert archive / Missouri / Flash Flood Warnings in 1998

Flash Flood Warning 41, NWS St. Louis, MO

August 18, 1998Saint Clair County, Illinois; Saint Louis County, City of Saint Louis, Missouri

NWS St. Louis, MO issued this flash flood warning at Aug 18, 1998, 7:11 AM CDT for Saint Clair County, Illinois; Saint Louis County, City of Saint Louis, Missouri. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Aug 18, 1998, 7:11 AM CDT (12:11 UTC)
Expired
Aug 18, 1998, 10:05 AM CDT
In force
3 hr
Issued by
NWS St. Louis, MO
Area
Whole counties

Counties Saint Clair County, IL, City of Saint Louis, MO, Saint Louis County, MO

The radar

The St Louis radar (KLSX), 45 km from the middle of the area, began a volume at 12:10 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

Lincoln, IL (KILX), launched 12:00Z, 0.2 hours before the alert went out and 222 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, Lincoln, IL at 12:00Z on 1998-08-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 78 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lincoln, IL at 12:00Z on 1998-08-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 41 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
78 J/kg
Mixed-layer CIN
-276 J/kg
Mixed-layer LCL
1033 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
41 m²/s²
0-3 km storm-relative helicity
103 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.5

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KSTL 181212
FFWSTL
ILC163-MOC189-510-181505-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
711 AM CDT TUE AUG 18 1998

THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  WESTERN ST CLAIR COUNTY IN SOUTHWESTERN ILLINOIS
  ST. LOUIS COUNTY IN EAST CENTRAL MISSOURI
  ST. LOUIS CITY IN EAST CENTRAL MISSOURI

* UNTIL 1005 AM CDT

* AT 700 AM A NARROW LINE OF THUNDERSTORMS WAS LOCATED FROM WATERLOO
  ILLINOIS...10 MILES SOUTHEAST OF THE ARCH...NORTH TO JERSEYVILLE
  ILLINOIS...25 MILES NORTH OF ST LOUIS. THESE STORMS ARE FOLLOWING
  ONE ANOTHER OVER THE SAME PATH...INCLUDING NORTH ST LOUIS COUNTY.
..
  THROUGH THE CITY OF ST LOUIS..INTO WESTERN ST. CLAIR COUNTY.

* PERSONS IN FLORISSANT AND EASTERN PARTS OF NORTH ST LOUIS COUNTY.
  THE CITY OF ST. LOUIS...AND SOUTH COUNTY ALONG INTERSTATE 55...
  ALONG WITH THE COLUMBIA AND WATERLOO AREA CAN EXPECT LOCAL
  RAINFALL AMOUNTS OF UP TO 2 TO 4 INCHES THROUGH 8 AM WITH MAJOR
  FLOODING OF SECONDARY AND LOW ROAD AREAS.

  THIS IS A VERY SERIOUS SITUATION. MUCH OF THIS RAIN IS FALLING ON
  AREAS WHERE THERE IS A LOT OF PAVEMENT. RUNOFF WILL BE HIGH
  AND WILL BE OCCURRING DURING THE MORNING RUSH HOUR. IF YOU SEE
  WATER ON THE ROAD...DON'T EVEN THINK ABOUT DRIVING INTO IT. IT
  COULD RISE VERY QUICKLY WHILE YOU ARE DRIVING THROUGH IT. TURN
  AROUND AND FIND AN ALTERNATE ROUTE!

  IF FLASH FLOODING IS OBSERVED OR IMMINENT...MOVE QUICKLY TO HIGHER
  GROUND. NEVER DRIVE INTO AN AREA WHERE WATER COVERS THE ROAD...
  ESPECIALLY LOW-WATER BRIDGES

  PEDIGO

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 18, 7:32 AM CDTFlash Flood WarningLSXMadison3 hr

Nearby

Flash Flood Warnings in Missouri, 1998Flash Flood Warnings in Illinois, 1998Every flash flood warning in 1998

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.