Alert archive / Iowa / Tornado Warnings in 1998

Tornado Warning 39, NWS Des Moines, IA

June 23, 1998Sac County, Iowa

NWS Des Moines, IA issued this tornado warning at Jun 23, 1998, 9:47 PM CDT for Sac County, Iowa. It was in force for 33 min. 2 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 23, 1998, 9:47 PM CDT (02:47 UTC)
Expired: Jun 23, 1998, 10:20 PM CDT
In force: 33 min
Issued by: NWS Des Moines, IA
Area: Whole counties

County Sac County, IA

The radar

The Des Moines radar (KDMX), 135 km from the middle of the area, began a volume at 02:48 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

Time	Report	Where	Remark
Jun 23, 10:06 PM CDT	Thunderstorm Wind 69	Sac City, IA
Jun 23, 10:18 PM CDT	Thunderstorm Wind 52	Lake View, 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.

Issued	Product	Office	Lasted
Jun 23, 7:30 PM CDT	Tornado Watch	SPC	6 hr

The nearest sounding before it

Minneapolis, MN (KMPX), launched 00:00Z, 2.8 hours before the alert went out and 300 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 901 J/kg
Mixed-layer CIN: -26 J/kg
Mixed-layer LCL: 1105 m above ground
0-6 km bulk shear: 59 kt
0-1 km storm-relative helicity: 212 m²/s²
0-3 km storm-relative helicity: 335 m²/s²
Significant tornado parameter: 1.4
Supercell composite: 8.6

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KDSM 240247 RRA
TORDSM
IAC161-240320-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
947 PM CDT TUE JUN 23 1998

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* TORNADO WARNING FOR...
  EASTERN SAC COUNTY IN WEST CENTRAL IOWA

* UNTIL 1020 PM CDT

* AT 945 PM CDT... DOPPLER RADAR INDICATED A DEVELOPING TORNADO 41
  MILES WEST OF FORT DODGE OR 1 MILE SOUTHEAST OF SAC CITY MOVING
  EAST NORTHEAST AT 30 MPH.

* THE TORNADO IS EXPECTED TO BE NEAR

  SAC CITY          NOW

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

SEARCY

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 23, 8:59 PM CDT	Severe Thunderstorm Warning	DMX	Sac	46 min
Jun 23, 9:25 PM CDT	Severe Thunderstorm Warning	DMX	Crawford	30 min
Jun 23, 9:52 PM CDT	Tornado Warning	DMX	Calhoun	33 min
Jun 23, 10:08 PM CDT	Severe Thunderstorm Warning	DMX	Calhoun, Carroll	47 min
Jun 23, 10:17 PM CDT	Severe Thunderstorm Warning	DMX	Webster	33 min
Jun 23, 10:19 PM CDT	Flash Flood Warning	DMX	Palo Alto	3 hr
Jun 23, 10:38 PM CDT	Severe Thunderstorm Warning	DMX	Humboldt	32 min
Jun 23, 10:41 PM CDT	Flash Flood Warning	DMX	Kossuth	4 hr
Jun 23, 10:41 PM CDT	Flash Flood Warning	DMX	Sac	4 hr
Jun 23, 10:54 PM CDT	Flash Flood Warning	DMX	Pocahontas	4 hr
Jun 23, 11:20 PM CDT	Flash Flood Warning	DMX	Crawford	4 hr
Jun 23, 11:31 PM CDT	Flash Flood Warning	DMX	Winnebago	4 hr
Jun 23, 11:34 PM CDT	Severe Thunderstorm Warning	DMX	Cerro Gordo, Franklin, Worth	31 min
Jun 23, 11:53 PM CDT	Flash Flood Warning	DMX	Calhoun	4 hr
Jun 23, 11:56 PM CDT	Severe Thunderstorm Warning	DMX	Butler	34 min
Jun 24, 12:34 AM CDT	Flash Flood Warning	DMX	Hamilton, Webster	4 hr
Jun 24, 2:35 AM CDT	Flash Flood Warning	DMX	Sac	4 hr
Jun 24, 2:50 AM CDT	Flash Flood Warning	DMX	Crawford	4 hr

Nearby

Tornado Warnings in Iowa, 1998 Every tornado warning in 1998 Tornadoes 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.