Alert archive / Iowa / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 307, NWS Des Moines, IA

October 29, 1998Poweshiek County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Oct 29, 1998, 5:01 PM CST for Poweshiek 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
Oct 29, 1998, 5:01 PM CST (23:01 UTC)
Expired
Oct 29, 1998, 5:35 PM CST
In force
34 min
Issued by
NWS Des Moines, IA
Area
Whole counties

County Poweshiek County, IA

The radar

The Des Moines radar (KDMX), 99 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.

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 11.0 hours before the alert went out and 169 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 292301
SVRDSM
IAC157-292335-

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

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  POWESHIEK COUNTY IN CENTRAL IOWA

* UNTIL 535 PM CST

* AT 459 PM CST... DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM 45
  MILES NORTH NORTHWEST OF OTTUMWA OR 8 MILES SOUTHWEST OF MALCOM...
  MOVING NORTHEAST AT 25 MPH.

* THIS STORM CAN BE EXPECTED NEAR...
   MALCOM             BY 519 PM CST
   BROOKLYN           BY 525 PM CST

THIS IS A DANGEROUS STORM WHICH WILL LIKELY PRODUCE LARGE HAIL! STAY
INDOORS AWAY FROM WINDOWS.

SEARCY/SMALL

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, 4:45 PM CSTSevere Thunderstorm WarningDMXTama20 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.