Alert archive / Illinois / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 87, NWS St. Louis, MO

May 6, 1998Macoupin County, Madison County, Illinois

NWS St. Louis, MO issued this severe thunderstorm warning at May 6, 1998, 9:54 PM CDT for Macoupin County, Madison County, Illinois. It was in force for 51 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
May 6, 1998, 9:54 PM CDT (02:54 UTC)
Expired
May 6, 1998, 10:45 PM CDT
In force
51 min
Issued by
NWS St. Louis, MO
Area
Whole counties

Counties Macoupin County, IL, Madison County, IL

The radar

The St Louis radar (KLSX), 77 km from the middle of the area, began a volume at 02:56 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, 2.9 hours before the alert went out and 167 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 1998-05-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 102 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, Lincoln, IL at 00:00Z on 1998-05-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 113 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
102 J/kg
Mixed-layer CIN
-9 J/kg
Mixed-layer LCL
507 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
113 m²/s²
0-3 km storm-relative helicity
180 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

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

787 
WUUS1 KSTL 070257 RRA
SVRSTL
ILC117-119-070345-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
954 PM CDT WED MAY 6 1998

THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  MACOUPIN COUNTY IN SOUTHWESTERN ILLINOIS
  NORTHWESTERN MADISON COUNTY ILLINOIS IN SOUTHWESTERN ILLINOIS

* UNTIL 1045 PM CDT

* AT 954 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM NEAR PORTAGE DES SIOUX... MOVING NORTHEAST AT
  25 MPH.

* LOCATIONS THAT WILL BE AFFECTED...
  ALTON
  BRIGHTON
  GODFREY

THE PRIMARY SEVERE WEATHER THREAT IS DAMAGING HAIL. LARGE HAIL CAN
CAUSE EXTENSIVE PROPERTY DAMAGE AN SERIOUS INJURY TO PEOPLE CAUGHT
OUTDOORS. MOVE INSIDE A STURDY BUILDING IMMEDIATELY.

TRUETT/RP

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

In the hours before

Special weather statement, May 6, 8:11 PM CDT, 1 hour 43 minutes before
MOZ099-070615-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
811 PM CDT WED MAY 6 1998

...A TORNADO WATCH IS NOW IN EFFECT FOR REYNOLDS COUNTY UNTIL 2 AM...

THE TORNADO WATCH THAT COVERED THE SOUTHERN THIRD OF MISSOURI HAS BEEN
REPLACED BY A NEW TORNADO WATCH THAT COVERS SOUTHWEST AND SOUTH CENTRAL
MISSOURI...INCLUDING REYNOLDS COUNTY.  THE NEW TORNADO WATCH...NUMBER
297...IS IN EFFECT UNTIL 2 AM CDT.

FERRY
Special weather statement, May 6, 8:11 PM CDT, 1 hour 43 minutes before
MOZ099-070615-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
811 PM CDT WED MAY 6 1998

...A TORNADO WATCH IS NOW IN EFFECT FOR REYNOLDS COUNTY UNTIL 2 AM...

THE TORNADO WATCH THAT COVERED THE SOUTHERN THIRD OF MISSOURI HAS BEEN
REPLACED BY A NEW TORNADO WATCH THAT COVERS SOUTHWEST AND SOUTH CENTRAL
MISSOURI...INCLUDING REYNOLDS COUNTY.  THE NEW TORNADO WATCH...NUMBER
297...IS IN EFFECT UNTIL 2 AM CDT.

FERRY

The office that day

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

IssuedProductOfficeCountiesLasted
May 6, 7:38 PM CDTSevere Thunderstorm WarningLSXPike62 min
May 6, 8:24 PM CDTTornado WarningLSXAdams31 min

Nearby

Severe Thunderstorm Warnings in Illinois, 1998Every severe thunderstorm 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.