Alert archive / Iowa / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 113, NWS Des Moines, IA

October 8, 1997Cass County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Oct 8, 1997, 6:07 PM CDT for Cass County, Iowa. It was in force for 33 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
Oct 8, 1997, 6:07 PM CDT (23:07 UTC)
Expired
Oct 8, 1997, 6:40 PM CDT
In force
33 min
Issued by
NWS Des Moines, IA
Area
Whole counties

County Cass County, IA

The radar

The Des Moines radar (KDMX), 110 km from the middle of the area, began a volume at 23:07 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 nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 11.1 hours before the alert went out and 120 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, Omaha, NE at 12:00Z on 1997-10-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 468 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, Omaha, NE at 12:00Z on 1997-10-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 241 square meters per square second.193958Sfc1 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
468 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
574 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
241 m²/s²
0-3 km storm-relative helicity
223 m²/s²
Significant tornado parameter
0.3
Supercell composite
1.9

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KDSM 082307 RRA
SVRDSM
IAC029-082340-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
607 PM CDT WED OCT 8 1997

* SEVERE THUNDERSTORM WARNING FOR
  CASS COUNTY - SOUTHWESTERN IOWA

* UNTIL 640 PM CDT
 
* SOME AREAS AFFECTED
    ATLANTIC
    GRISWOLD
    ANITA

* AT 605 PM CDT RADAR INDICATED A SEVERE THUNDERSTORM NEAR RED OAK...OR
  40 MILES SOUTHEAST OF OMAHA MOVING NORTHEAST AT 60 MPH.

* THE STORM WILL BE NEAR ATLANTIC BY 620 PM .

THIS IS A DANGEROUS STORM.  WIND GUSTS OVER 60 MPH ARE LIKELY WITH
THIS STORM.  DO NOT GO OUTDOORS.

SMALL

Nearby

Severe Thunderstorm Warnings in Iowa, 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.