Alert archive / Iowa / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 331, NWS Des Moines, IA

September 7, 2001Dallas County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Sep 7, 2001, 2:28 PM CDT for Dallas County, Iowa. It was in force for 42 min. 1 report came from inside the area while it was in force.

The area

The outline the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties, with what was reported inside it.

The facts

Issued
Sep 7, 2001, 2:28 PM CDT (19:28 UTC)
Expired
Sep 7, 2001, 3:10 PM CDT
In force
42 min
Issued by
NWS Des Moines, IA
Area
Whole counties; the outline is the Mesonet’s reconstruction

County Dallas County, IA

What was reported inside it

TimeReportWhereRemark
Sep 7, 2:58 PM CDTThunderstorm Wind 52 EWaukee, 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, 7.5 hours before the alert went out and 299 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 2001-09-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1137 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Davenport, at 12:00Z on 2001-09-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 223 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
1137 J/kg
Mixed-layer CIN
-44 J/kg
Mixed-layer LCL
827 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
223 m²/s²
0-3 km storm-relative helicity
184 m²/s²
Significant tornado parameter
0.8
Supercell composite
2.7

Open this sounding in Storm Lab

The text

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

607 
WUUS53 KDMX 071928
SVRDSM
IAC049-072010-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
228 PM CDT FRI SEP 7 2001

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

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

* UNTIL 310 PM CDT

* AT 226 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM OVER DALLAS CENTER...OR ABOUT 25 MILES WEST OF
  DES MOINES...MOVING EAST AT 25 MPH.

* THE SEVERE THUNDERSTORM WILL BE...
  7 MILES NORTH OF WAUKEE AROUND 250 PM

DAMAGING WINDS OF 60 TO 70 MILES AN HOUR ARE LIKELY IN THE WARNED
AREA.

DAMAGING STRAIGHT-LINE WINDS OVER 75 MPH CAN SOUND JUST LIKE A
TORNADO AND CAUSE JUST AS MUCH DAMAGE.

LAT...LON 4184 9429 4151 9424 4152 9382 4186 9383

JOHNSON

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 7, 7:47 AM CDTSevere Thunderstorm WarningDMXPolk28 min
Sep 7, 8:23 AM CDTSevere Thunderstorm WarningDMXPolk, Warren42 min
Sep 7, 3:04 PM CDTSevere Thunderstorm WarningDMXPolk41 min
Sep 7, 3:12 PM CDTSevere Thunderstorm WarningDMXStory38 min
Sep 7, 3:21 PM CDTSevere Thunderstorm WarningDMXHardin, Marshall44 min
Sep 7, 3:41 PM CDTSevere Thunderstorm WarningDMXButler, Grundy39 min
Sep 7, 4:01 PM CDTSevere Thunderstorm WarningDMXBlack Hawk, Bremer39 min
Sep 7, 4:20 PM CDTSevere Thunderstorm WarningDMXButler25 min
Sep 7, 4:40 PM CDTSevere Thunderstorm WarningDMXBremer20 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2001Every severe thunderstorm warning in 2001

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.