Alert archive / Iowa / Tornado Warnings in 2002

Tornado Warning 5, NWS Quad Cities, IA

April 18, 2002Johnson County, Iowa

NWS Quad Cities, IA issued this tornado warning at Apr 18, 2002, 8:59 PM CDT for Johnson County, Iowa. It was in force for 46 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: Apr 18, 2002, 8:59 PM CDT (01:59 UTC)
Expired: Apr 18, 2002, 9:45 PM CDT
In force: 46 min
Issued by: NWS Quad Cities, IA
Area: Counties, with a storm outline in the text

County Johnson County, IA

The radar

The Quad Cities radar (KDVN), 90 km from the middle of the area, began a volume at 01:59 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
Apr 18, 9:05 PM CDT	Hail 0.75	Tiffin, IA
Apr 18, 9:20 PM CDT	Thunderstorm Wind 61 E	Coralville, IA	Semi tractor trailer blown over.

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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Apr 18, 8:30 PM CDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 2.0 hours before the alert went out and 96 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: 1636 J/kg
Mixed-layer CIN: -24 J/kg
Mixed-layer LCL: 1702 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 113 m²/s²
0-3 km storm-relative helicity: 200 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 4.3

Open this sounding in Storm Lab

The text

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

000 
WFUS53 KDVN 190159
TORMLI
IAC103-190245-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
858 PM CDT THU APR 18 2002

THE NATIONAL WEATHER SERVICE IN THE QUAD CITIES HAS ISSUED A

* TORNADO WARNING FOR...
  JOHNSON COUNTY IN EAST CENTRAL IOWA

* UNTIL 945 PM CDT

* AT 854 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM WITH A POSSIBLE TORNADO 6 MILES WEST OF
  OXFORD...OR 9 MILES SOUTHEAST OF MARENGO...MOVING EAST AT 40 MPH.

* THE TORNADO IS EXPECTED TO BE NEAR...
   OXFORD BY 905 PM CDT.
   KENT COUNTY PARK BY 910 PM CDT.
   NORTH LIBERTY BY 915 PM CDT.
   ELMIRA BY 925 PM CDT.

THE SAFEST PLACE TO BE DURING A TORNADO IS IN A BASEMENT OR ON THE
LOWEST FLOOR OF A BUILDING IN AN INTERIOR HALLWAY OR ROOM.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 100 AM CDT FRIDAY
MORNING FOR EASTERN IOWA AND NORTHWEST ILLINOIS AND NORTHEAST
MISSOURI.

LAT...LON 4185 9183 4152 9182 4152 9139 4185 9139

WOLF

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 18, 7:51 PM CDT	Severe Thunderstorm Warning	DVN	Benton	34 min
Apr 18, 7:55 PM CDT	Tornado Warning	DVN	Benton	35 min
Apr 18, 8:09 PM CDT	Tornado Warning	DVN	Buchanan	36 min
Apr 18, 8:17 PM CDT	Severe Thunderstorm Warning	DVN	Linn	33 min
Apr 18, 8:27 PM CDT	Tornado Warning	DVN	Iowa	48 min
Apr 18, 8:35 PM CDT	Tornado Warning	DVN	Jones, Linn	35 min
Apr 18, 8:44 PM CDT	Severe Thunderstorm Warning	DVN	Dubuque	31 min
Apr 18, 9:16 PM CDT	Severe Thunderstorm Warning	DVN	Jackson	44 min
Apr 18, 9:28 PM CDT	Tornado Warning	DVN	Cedar	32 min
Apr 18, 9:30 PM CDT	Severe Thunderstorm Warning	DVN	Clinton, Jones	45 min
Apr 18, 9:50 PM CDT	Severe Thunderstorm Warning	DVN	Scott	40 min
Apr 18, 9:59 PM CDT	Severe Thunderstorm Warning	DVN	Jackson	51 min

Nearby

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