Alert archive / Iowa / Tornado Warnings in 2002

Tornado Warning 21, NWS Quad Cities, IA

September 18, 2002Clinton County, Jackson County, Iowa

NWS Quad Cities, IA issued this tornado warning at Sep 18, 2002, 2:29 PM CDT for Clinton County, Jackson County, Iowa. It was in force for 46 min. 8 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
Sep 18, 2002, 2:29 PM CDT (19:29 UTC)
Expired
Sep 18, 2002, 3:15 PM CDT
In force
46 min
Issued by
NWS Quad Cities, IA
Area
Counties, with a storm outline in the text

Counties Clinton County, IA, Jackson County, IA

The radar

The Quad Cities radar (KDVN), 47 km from the middle of the area, began a volume at 19:28 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
Sep 18, 2:40 PM CDTHail 2.75Maquoketa, IA
Sep 18, 2:40 PM CDTThunderstorm Wind 61 EMaquoketa, IA
Sep 18, 2:42 PM CDTThunderstorm Wind 70 EBaldwin, IA
Sep 18, 2:42 PM CDTHail 2.5Baldwin, IA
Sep 18, 2:51 PM CDTHail 2.75Maquoketa, IA
Sep 18, 2:51 PM CDTHail 1Maquoketa, IA
Sep 18, 3:20 PM CDTThunderstorm Wind 61 EGoose Lake, IA
Sep 18, 3:20 PM CDTHail 1Goose Lake, 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 46 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 2002-09-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 82 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 2002-09-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 111 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
82 J/kg
Mixed-layer CIN
-38 J/kg
Mixed-layer LCL
783 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
111 m²/s²
0-3 km storm-relative helicity
142 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The office that day

Everything else NWS Quad Cities, IA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 18, 1:55 PM CDTSevere Thunderstorm WarningDVNJones50 min
Sep 18, 2:09 PM CDTTornado WarningDVNJones36 min
Sep 18, 3:17 PM CDTSevere Thunderstorm WarningDVNClinton43 min
Sep 18, 3:38 PM CDTSevere Thunderstorm WarningDVNCarroll, Whiteside52 min

Nearby

Tornado Warnings in Iowa, 2002Every tornado warning in 2002Tornadoes 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.