Alert archive / Iowa / Tornado Warnings in 1998

Tornado Warning 38, NWS Des Moines, IA

June 18, 1998Polk County, Iowa

NWS Des Moines, IA issued this tornado warning at Jun 18, 1998, 2:16 PM CDT for Polk County, Iowa. It was in force for 34 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
Jun 18, 1998, 2:16 PM CDT (19:16 UTC)
Expired
Jun 18, 1998, 2:50 PM CDT
In force
34 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 19:19 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
Jun 18, 2:10 PM CDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 7.3 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 1998-06-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 245 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 1998-06-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -105 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
245 J/kg
Mixed-layer CIN
-251 J/kg
Mixed-layer LCL
1451 m above ground
0-6 km bulk shear
67 kt
0-1 km storm-relative helicity
-105 m²/s²
0-3 km storm-relative helicity
-51 m²/s²
Significant tornado parameter
0.0
Supercell composite
-1.0

Open this sounding in Storm Lab

The text

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

372 
WFUS1 KDSM 181917 RRA
TORDSM
IAC153-181950-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
216 PM CDT THU JUN 18 1998

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

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

* UNTIL 250 PM CDT

* AT 214 PM CDT... DOPPLER RADAR INDICATED A TORNADO 12 MILES SOUTH
  OF DES MOINES OR 11 MILES SOUTH SOUTHWEST OF PLEASANT HILL MOVING
  NORTH NORTHEAST AT 35 MPH.

* THIS TORNADO CAN BE EXPECTED NEAR...
   DES MOINES         BY 222 PM CDT
   PLEASANT HILL      BY 230 PM CDT
   ALTOONA            BY 242 PM CDT

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

FILLBACH

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 18, 3:35 AM CDTSevere Thunderstorm WarningDMXEmmet30 min
Jun 18, 9:12 AM CDTSevere Thunderstorm WarningDMXAdair, Cass, Guthrie33 min
Jun 18, 10:05 AM CDTSevere Thunderstorm WarningDMXWebster35 min
Jun 18, 10:41 AM CDTSevere Thunderstorm WarningDMXMarion34 min
Jun 18, 10:45 AM CDTSevere Thunderstorm WarningDMXBoone, Webster35 min
Jun 18, 10:54 AM CDTSevere Thunderstorm WarningDMXPolk31 min
Jun 18, 11:06 AM CDTSevere Thunderstorm WarningDMXJasper34 min
Jun 18, 11:12 AM CDTSevere Thunderstorm WarningDMXWarren33 min
Jun 18, 11:15 AM CDTSevere Thunderstorm WarningDMXMarshall, Story35 min
Jun 18, 11:21 AM CDTSevere Thunderstorm WarningDMXMarion34 min
Jun 18, 11:22 AM CDTSevere Thunderstorm WarningDMXPolk33 min
Jun 18, 11:36 AM CDTSevere Thunderstorm WarningDMXJasper34 min
Jun 18, 11:40 AM CDTSevere Thunderstorm WarningDMXBoone35 min
Jun 18, 11:43 AM CDTSevere Thunderstorm WarningDMXHardin32 min
Jun 18, 11:50 AM CDTSevere Thunderstorm WarningDMXMarshall, Story30 min
Jun 18, 12:01 PM CDTSevere Thunderstorm WarningDMXHamilton, Webster34 min
Jun 18, 12:55 PM CDTSevere Thunderstorm WarningDMXWinnebago, Worth30 min
Jun 18, 1:30 PM CDTSevere Thunderstorm WarningDMXDallas, Polk35 min
Jun 18, 1:33 PM CDTSevere Thunderstorm WarningDMXUnion32 min
Jun 18, 1:56 PM CDTTornado WarningDMXWarren34 min
Jun 18, 1:59 PM CDTFlash Flood WarningDMXDallas3 hr
Jun 18, 2:09 PM CDTSevere Thunderstorm WarningDMXPolk31 min
Jun 18, 2:16 PM CDTFlash Flood WarningDMXPolk3 hr
Jun 18, 2:19 PM CDTFlash Flood WarningDMXStory3 hr
Jun 18, 2:35 PM CDTFlash Flood WarningDMXMadison3 hr
Jun 18, 3:03 PM CDTSevere Thunderstorm WarningDMXMahaska, Marion32 min
Jun 18, 3:12 PM CDTSevere Thunderstorm WarningDMXPoweshiek28 min
Jun 18, 3:16 PM CDTSevere Thunderstorm WarningDMXBlack Hawk, Tama34 min
Jun 18, 3:34 PM CDTSevere Thunderstorm WarningDMXDavis, Wapello31 min
Jun 18, 5:04 PM CDTFlash Flood WarningDMXPolk, Story2 hr

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.