Alert archive / Iowa / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 61, NWS Des Moines, IA

June 21, 1997Wapello County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Jun 21, 1997, 3:53 AM CDT for Wapello County, Iowa. It was in force for 32 min. 1 report came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Jun 21, 1997, 3:53 AM CDT (08:53 UTC)
Expired
Jun 21, 1997, 4:25 AM CDT
In force
32 min
Issued by
NWS Des Moines, IA
Area
Whole counties

County Wapello County, IA

The radar

The Des Moines radar (KDMX), 134 km from the middle of the area, began a volume at 08:54 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.

What was reported inside it

TimeReportWhereRemark
Jun 21, 3:58 AM CDTThunderstorm Wind 57Ottumwa, IA

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The watch it was issued in

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

IssuedProductOfficeLasted
Jun 21, 1:30 AM CDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 8.9 hours before the alert went out and 172 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 1997-06-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4926 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 1997-06-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 67 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
4926 J/kg
Mixed-layer CIN
-12 J/kg
Mixed-layer LCL
969 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
67 m²/s²
0-3 km storm-relative helicity
216 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KDSM 210852 RRA
SVRDSM
IAC179-210925-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
353 AM CDT SAT JUN 21 1997

* SEVERE THUNDERSTORM WARNING FOR
  WAPELLO COUNTY - SOUTHEASTERN IOWA

* UNTIL 425 AM CDT
 
* SOME AREAS AFFECTED
    OTTUMWA
    AGENCY

* AT 350 AM CDT RADAR INDICATED A SEVERE THUNDERSTORM 15 MILES
  NORTHWEST OF OTTUMWA MOVING EAST AT 45 MPH.

* THE STORM WILL BE IN OTTUMWA BY 4 AM CDT.

THIS IS A DANGEROUS STORM.  THIS STORM HAS A HISTORY OF SIGNIFICANT
WIND DAMAGE.  DO NOT GO OUTDOORS.

FAB

The office that day

Everything else NWS Des Moines, IA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 20, 10:14 PM CDTSevere Thunderstorm WarningDMXWright31 min
Jun 20, 10:20 PM CDTSevere Thunderstorm WarningDMXWebster35 min
Jun 20, 10:30 PM CDTSevere Thunderstorm WarningDMXFranklin30 min
Jun 20, 11:01 PM CDTSevere Thunderstorm WarningDMXFranklin34 min
Jun 20, 11:33 PM CDTSevere Thunderstorm WarningDMXHardin32 min
Jun 20, 11:39 PM CDTSevere Thunderstorm WarningDMXButler, Grundy31 min
Jun 21, 12:04 AM CDTSevere Thunderstorm WarningDMXGrundy, Hardin31 min
Jun 21, 12:21 AM CDTSevere Thunderstorm WarningDMXBlack Hawk, Grundy44 min
Jun 21, 12:28 AM CDTTornado WarningDMXBlack Hawk32 min
Jun 21, 1:41 AM CDTSevere Thunderstorm WarningDMXAudubon, Cass34 min
Jun 21, 2:39 AM CDTSevere Thunderstorm WarningDMXClarke, Warren31 min
Jun 21, 2:51 AM CDTSevere Thunderstorm WarningDMXPolk, Warren34 min
Jun 21, 3:06 AM CDTSevere Thunderstorm WarningDMXLucas, Marion29 min
Jun 21, 3:21 AM CDTSevere Thunderstorm WarningDMXMahaska, Monroe34 min
Jun 21, 4:27 PM CDTTornado WarningDMXCalhoun, Webster33 min

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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.