Alert archive / Missouri / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 71, NWS St. Louis, MO

May 18, 1997Knox County, Missouri

NWS St. Louis, MO issued this severe thunderstorm warning at May 18, 1997, 10:03 PM CDT for Knox County, Missouri. It was in force for 42 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 18, 1997, 10:03 PM CDT (03:03 UTC)
Expired
May 18, 1997, 10:45 PM CDT
In force
42 min
Issued by
NWS St. Louis, MO
Area
Whole counties

County Knox County, MO

The radar

The St Louis radar (KLSX), 203 km from the middle of the area, began a volume at 03:07 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
May 18, 5:30 PM CDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 3.1 hours before the alert went out and 216 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, Davenport, at 00:00Z on 1997-05-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2339 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, Davenport, at 00:00Z on 1997-05-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 145 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
2339 J/kg
Mixed-layer CIN
-25 J/kg
Mixed-layer LCL
1544 m above ground
0-6 km bulk shear
49 kt
0-1 km storm-relative helicity
145 m²/s²
0-3 km storm-relative helicity
165 m²/s²
Significant tornado parameter
1.0
Supercell composite
9.0

Open this sounding in Storm Lab

The text

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

102 
WUUS1 KSTL 190305 RRA
SVRSTL
MOC103-190345-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
1003 PM CDT SUN MAY 18 1997
 
THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS EXTENDED THE
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL 1045 PM CDT
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN NORTHEAST MISSOURI
 
   ...KNOX COUNTY
 
AT 10 PM...THE NATIONAL WEATHER SERVICE WAS DETECTING A SEVERE
THUNDERSTORM NEAR EDINA. IT WAS MOVING TO THE SOUTHEAST AT 30 MPH. IT
WILL MOVE THROUGH EDINA...KNOX CITY...PLEVNA AND NEWARK.
 
THIS STORM HAS A HISTORY OF DAMAGING HAIL. STAY INSIDE AND AWAY
FROM WINDOWS.
 
GKS/AMS

The office that day

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

IssuedProductOfficeCountiesLasted
May 18, 8:02 PM CDTSevere Thunderstorm WarningLSXScotland43 min
May 18, 8:22 PM CDTSevere Thunderstorm WarningLSXClark53 min
May 18, 8:40 PM CDTSevere Thunderstorm WarningLSXKnox50 min
May 18, 9:20 PM CDTSevere Thunderstorm WarningLSXKnox, Scotland40 min
May 18, 9:35 PM CDTSevere Thunderstorm WarningLSXLewis55 min
May 18, 10:21 PM CDTFlash Flood WarningLSXKnox3 hr
May 18, 10:49 PM CDTSevere Thunderstorm WarningLSXKnox41 min

Nearby

Severe Thunderstorm Warnings in Missouri, 1997Every severe thunderstorm warning in 1997

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.