Alert archive / Iowa / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 239, NWS Des Moines, IA

October 4, 2002Story County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Oct 4, 2002, 3:23 AM CDT for Story County, Iowa. It was in force for 22 min. 2 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Oct 4, 2002, 3:23 AM CDT (08:23 UTC)
Expired: Oct 4, 2002, 3:45 AM CDT
In force: 22 min
Issued by: NWS Des Moines, IA
Area: Counties, with a storm outline in the text

County Story County, IA

The radar

The Des Moines radar (KDMX), 46 km from the middle of the area, began a volume at 08:26 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
Oct 4, 3:30 AM CDT	Thunderstorm Wind 65 E	Fernald, IA
Oct 4, 3:31 AM CDT	Thunderstorm Wind 50 E	Colo, 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 00:00Z, 8.4 hours before the alert went out and 246 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 602 m above ground
0-6 km bulk shear: 50 kt
0-1 km storm-relative helicity: 128 m²/s²
0-3 km storm-relative helicity: 149 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.

617 
WUUS53 KDMX 040823
SVRDSM
IAC169-040845-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
323 AM CDT FRI OCT 4 2002

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  EASTERN STORY COUNTY IN CENTRAL IOWA

* UNTIL 345 AM CDT

* AT 320 AM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A LINE
  OF SEVERE THUNDERSTORMS FROM 9 MILES WEST OF MCCALLSBURG TO 5 MILES
  SOUTHWEST OF MAXWELL...OR FROM 38 MILES SOUTHEAST OF FORT DODGE TO
  21 MILES NORTH OF DES MOINES...MOVING NORTHEAST AT 55 MPH.

* SEVERE THUNDERSTORMS WILL BE...

  NEAR MCCALLSBURG AROUND 330 AM AND
  NEAR ZEARING AROUND 335 AM.

VERY STRONG WINDS UP TO 65 MPH ARE LIKELY IN THE WARNED AREA.

MOVE TO AN INTERIOR ROOM AND STAY AWAY FROM WINDOWS. IF YOU LIVE IN A
MOBILE HOME...SEEK SHELTER IN A STURDY BUILDING.

LAT...LON 4220 9351 4196 9352 4186 9350 4188 9325
          4219 9327 4220 9326

KULA

The office that day

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

Issued	Product	Office	Counties	Lasted
Oct 4, 2:35 AM CDT	Severe Thunderstorm Warning	DMX	Boone, Dallas, Greene	25 min
Oct 4, 3:29 AM CDT	Severe Thunderstorm Warning	DMX	Franklin	31 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2002 Every severe thunderstorm warning in 2002

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.