Alert archive / Iowa / Tornado Warnings in 1998

Tornado Warning 50, NWS Des Moines, IA

June 29, 1998Polk County, Iowa

NWS Des Moines, IA issued this tornado warning at Jun 29, 1998, 1:32 PM CDT for Polk County, Iowa. It was in force for 33 min. 13 reports 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 29, 1998, 1:32 PM CDT (18:32 UTC)
Expired
Jun 29, 1998, 2:05 PM CDT
In force
33 min
Issued by
NWS Des Moines, IA
Area
Whole counties

County Polk County, IA

The radar

The Des Moines radar (KDMX), 13 km from the middle of the area, began a volume at 18:33 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 29, 1:41 PM CDTTornado F2Grimes, IA
Jun 29, 1:43 PM CDTThunderstorm Wind 69Johnston, IA
Jun 29, 1:46 PM CDTThunderstorm Wind 61Ankeny, IA
Jun 29, 1:47 PM CDTThunderstorm Wind 61West Des Moines, IA
Jun 29, 1:47 PM CDTThunderstorm Wind 104Johnston, IA
Jun 29, 1:48 PM CDTThunderstorm Wind 61Urbandale, IA
Jun 29, 1:49 PM CDTThunderstorm Wind 69Saylorville, IA
Jun 29, 1:50 PM CDTThunderstorm Wind 104Des Moines, IA
Jun 29, 1:54 PM CDTThunderstorm Wind 55Des Moines Arpt, IA
Jun 29, 1:55 PM CDTThunderstorm Wind 61Urbandale, IA
Jun 29, 2:00 PM CDTThunderstorm Wind 80Des Moines, IA
Jun 29, 2:00 PM CDTThunderstorm Wind 80Altoona, IA
Jun 29, 2:05 PM CDTThunderstorm Wind 87Des Moines, 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 29, 1:00 PM CDTTornado WatchSPC4 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 6.5 hours before the alert went out and 236 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 1998-06-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2006 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 1998-06-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 71 square meters per square second.1939587897Sfc1 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
2006 J/kg
Mixed-layer CIN
-188 J/kg
Mixed-layer LCL
850 m above ground
0-6 km bulk shear
59 kt
0-1 km storm-relative helicity
71 m²/s²
0-3 km storm-relative helicity
154 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.1

Open this sounding in Storm Lab

The text

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

864 
WFUS1 KDSM 291833 RRA
TORDSM
IAC153-291905-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
132 PM CDT MON JUN 29 1998

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* TORNADO WARNING FOR...
  POLK COUNTY IN CENTRAL IOWA

* UNTIL 205 PM CDT

* AT 131 PM CDT... DOPPLER RADAR INDICATED A DEVELOPING TORNADO 19
  MILES NORTHWEST OF DES MOINES OR 8 MILES WEST NORTHWEST OF POLK
  CITY MOVING EAST SOUTHEAST AT 40 MPH.

* THIS TORNADO CAN BE EXPECTED NEAR...
   POLK CITY          BY 137 PM CDT
   SAYLORVILLE RESERVOIR BY 139 PM CDT
   JOHNSTON           BY 142 PM CDT
   ANKENY             BY 146 PM CDT
   URBANDALE          BY 149 PM CDT
   DES MOINES         BY 154 PM CDT

GO TO THE BASEMENT OR A SMALL INTERIOR ROOM ON THE LOWEST FLOOR

COGIL

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 29, 12:18 PM CDTSevere Thunderstorm WarningDMXCarroll47 min
Jun 29, 12:24 PM CDTSevere Thunderstorm WarningDMXCalhoun36 min
Jun 29, 12:32 PM CDTTornado WarningDMXHamilton33 min
Jun 29, 12:37 PM CDTSevere Thunderstorm WarningDMXWebster48 min
Jun 29, 12:41 PM CDTTornado WarningDMXCrawford49 min
Jun 29, 12:59 PM CDTSevere Thunderstorm WarningDMXHardin51 min
Jun 29, 1:09 PM CDTSevere Thunderstorm WarningDMXStory36 min
Jun 29, 1:17 PM CDTSevere Thunderstorm WarningDMXBoone33 min
Jun 29, 1:20 PM CDTSevere Thunderstorm WarningDMXMarshall50 min
Jun 29, 1:23 PM CDTTornado WarningDMXBoone, Dallas32 min
Jun 29, 1:39 PM CDTSevere Thunderstorm WarningDMXDallas31 min
Jun 29, 1:44 PM CDTSevere Thunderstorm WarningDMXJasper, Tama46 min
Jun 29, 1:48 PM CDTTornado WarningDMXDallas, Madison47 min
Jun 29, 1:53 PM CDTSevere Thunderstorm WarningDMXWarren32 min
Jun 29, 2:04 PM CDTSevere Thunderstorm WarningDMXPolk21 min
Jun 29, 2:08 PM CDTSevere Thunderstorm WarningDMXPoweshiek47 min
Jun 29, 2:08 PM CDTSevere Thunderstorm WarningDMXMarion47 min
Jun 29, 2:11 PM CDTSevere Thunderstorm WarningDMXMadison34 min
Jun 29, 2:18 PM CDTTornado WarningDMXTama32 min
Jun 29, 2:23 PM CDTTornado WarningDMXMarion32 min
Jun 29, 2:28 PM CDTSevere Thunderstorm WarningDMXLucas, Mahaska, Monroe62 min
Jun 29, 2:28 PM CDTSevere Thunderstorm WarningDMXClarke, Warren62 min
Jun 29, 2:44 PM CDTSevere Thunderstorm WarningDMXWapello66 min
Jun 29, 2:55 PM CDTSevere Thunderstorm WarningDMXAppanoose, Davis65 min
Jun 29, 3:10 PM CDTTornado WarningDMXDavis35 min
Jun 29, 3:25 PM CDTTornado WarningDMXDallas50 min
Jun 29, 3:27 PM CDTSevere Thunderstorm WarningDMXGuthrie48 min
Jun 29, 3:40 PM CDTTornado WarningDMXPolk35 min
Jun 29, 3:47 PM CDTTornado WarningDMXWarren33 min
Jun 29, 4:05 PM CDTSevere Thunderstorm WarningDMXJasper, Marion50 min
Jun 29, 5:41 PM CDTSevere Thunderstorm WarningDMXClarke49 min
Jun 29, 5:44 PM CDTSevere Thunderstorm WarningDMXTaylor51 min
Jun 29, 6:00 PM CDTSevere Thunderstorm WarningDMXRinggold35 min
Jun 29, 6:19 PM CDTSevere Thunderstorm WarningDMXDecatur66 min
Jun 29, 6:25 PM CDTSevere Thunderstorm WarningDMXAppanoose, Wayne65 min

Nearby

Tornado Warnings in Iowa, 1998Every tornado warning in 1998Tornadoes 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.