Alert archive / Illinois / Flash Flood Warnings in 1998

Flash Flood Warning 39, NWS St. Louis, MO

August 5, 1998Montgomery County, Illinois

NWS St. Louis, MO issued this flash flood warning at Aug 5, 1998, 1:52 AM CDT for Montgomery County, Illinois. 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 5, 1998, 1:52 AM CDT (06:52 UTC)
Expired
Aug 5, 1998, 4:55 AM CDT
In force
3 hr
Issued by
NWS St. Louis, MO
Area
Whole counties

County Montgomery County, IL

The radar

The Lincoln radar (KILX), 103 km from the middle of the area, began a volume at 06:52 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 00:00Z, 6.9 hours before the alert went out and 127 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 00:00Z on 1998-08-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 421 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 00:00Z on 1998-08-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 44 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
421 J/kg
Mixed-layer CIN
-53 J/kg
Mixed-layer LCL
1463 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
44 m²/s²
0-3 km storm-relative helicity
67 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.5

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KSTL 050653
FFWSTL
ILC135-050955-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
152 AM CDT WED AUG 5 1998

THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  MONTGOMERY COUNTY ILLINOIS IN SOUTHWESTERN ILLINOIS

* UNTIL 455 AM CDT

* AT 145 AM...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
  DETECT SCATTERED SHOWERS AND THUNDERSTORMS MOVING NORTHEASTWARD
  THROUGH MONTGOMERY COUNTY ILLINOIS.  A CLUSTER OF STORMS IN THE ST
  LOUIS METRO WILL MOVE NORTHEASTWARD INTO MONTGOMERY COUNTY BY
  230 TO 330 AM.  ADDITIONAL RAIN AMOUNTS OF UP TO ONE INCH ARE
  POSSIBLE DURING THE NEXT TWO OR THREE HOURS.

* ALTHOUGH THE RAIN HAS LESSENED IN INTENSITY DURING THE LAST HOUR
  ...THE RADAR ESTIMATED AMOUNTS OF 3 TO AS HIGH AS 6 INCHES OF RAIN
  HAVE FALLEN BETWEEN LITCHFIELD AND NOKOMIS SINCE AROUND 7 PM
  THIS EVENING.  PORTIONS OF ROUTE 16 HAVE BEEN CLOSED BETWEEN
  LITCHFIELD AND NOKOMIS WITH 2 TO 4 FEET OF WATER ON THE ROAD.
  FLOODING PROBLEMS WILL CONTINUE FOR THE NEXT FEW HOURS AS RUNOFF
  CONTINUES.

  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

  BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
  DANGERS OF FLOODING. IT IS VERY DIFFICULT AT NIGHT TO TELL HOW
  DEEP THE WATER MAY BE. MOTORISTS SHOULD NEVER DRIVE THROUGH WATER
  OF UNKNOWN DEPTH.

&
GKS

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 4, 9:21 PM CDTSevere Thunderstorm WarningLSXFayette, Montgomery49 min
Aug 4, 9:45 PM CDTFlash Flood WarningLSXMontgomery4 hr
Aug 5, 2:38 AM CDTFlash Flood WarningLSXMarion3 hr

Nearby

Flash 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.