Alert archive / Iowa / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 306, NWS Des Moines, IA

October 29, 1998Tama County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Oct 29, 1998, 4:45 PM CST for Tama County, Iowa. It was in force for 20 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
Oct 29, 1998, 4:45 PM CST (22:45 UTC)
Expired
Oct 29, 1998, 5:05 PM CST
In force
20 min
Issued by
NWS Des Moines, IA
Area
Whole counties

County Tama County, IA

The radar

The Des Moines radar (KDMX), 106 km from the middle of the area, began a volume at 22:46 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
Oct 29, 4:55 PM CSTHail 1Montour, IA
Oct 29, 5:05 PM CSTHail 1.75Tama, 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 nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 10.8 hours before the alert went out and 176 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 12:00Z on 1998-10-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 12:00Z on 1998-10-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 189 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
901 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
189 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 292245
SVRDSM
IAC171-292305-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
445 PM CST THU OCT 29 1998

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHWESTERN TAMA COUNTY IN CENTRAL IOWA

* UNTIL 505 PM CST

* AT 444 PM CST... DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM 40
  MILES SOUTH SOUTHWEST OF WATERLOO OR 2 MILES WEST OF MONTOUR...
  MOVING NORTHEAST AT 25 MPH.

* THIS STORM CAN BE EXPECTED NEAR...
   MONTOUR            BY 447 PM CST

THIS IS A DANGEROUS STORM! STAY INDOORS AWAY FROM WINDOWS.

SMALL/SEARCY

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 29, 4:34 PM CSTSevere Thunderstorm WarningDMXMarshall21 min
Oct 29, 5:01 PM CSTSevere Thunderstorm WarningDMXPoweshiek34 min
Oct 29, 5:09 PM CSTSevere Thunderstorm WarningDMXTama31 min

Nearby

Severe Thunderstorm Warnings in Iowa, 1998Every severe thunderstorm warning 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.