Alert archive / Iowa / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 45, NWS Des Moines, IA

April 18, 2002Jasper County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Apr 18, 2002, 7:02 PM CDT for Jasper County, Iowa. It was in force for 58 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, 7:02 PM CDT (00:02 UTC)
Expired: Apr 18, 2002, 8:00 PM CDT
In force: 58 min
Issued by: NWS Des Moines, IA
Area: Counties, with a storm outline in the text

County Jasper County, IA

The radar

The Des Moines radar (KDMX), 51 km from the middle of the area, began a volume at 00:06 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, 7:42 PM CDT	Hail 0.88	Reasnor, IA
Apr 18, 8:06 PM CDT	Hail 0.88	Newton, 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 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, 4:15 PM CDT	Tornado Watch	SPC	5 hr

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 0.0 hours before the alert went out and 217 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 
WUUS53 KDMX 190002
SVRDSM
IAC099-190100-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
702 PM CDT THU APR 18 2002

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

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

* UNTIL 800 PM CDT

* AT 659 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM 11 MILES WEST OF COLFAX...OR ABOUT 14 MILES
  NORTHEAST OF DES MOINES...MOVING EAST AT 20 MPH.

* THE SEVERE THUNDERSTORM WILL BE...

  4 MILES NORTH OF COLFAX AROUND 725 PM AND
  NEAR NEWTON AROUND 750 PM.

DAMAGING HAIL UP TO THE SIZE OF GOLFBALLS IS LIKELY IN THE WARNED
AREA.

HURRICANE FORCE WINDS OF 70 TO 80 MILES AN HOUR ARE LIKELY IN THE
WARNED AREA.

STAY AWAY FROM WINDOWS DURING A SEVERE STORM...WIND GUSTS OVER 70 MPH
COULD BLOW THEM OUT.

REMEMBER...SEVERE THUNDERSTORMS CAN PRODUCE TORNADOES WITH LITTLE OR
NO ADVANCE WARNING.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 900 PM THURSDAY EVENING FOR
IOWA.

LAT...LON 4185 9335 4152 9331 4153 9278 4185 9278

KULA/FORSTER

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 18, 7:04 PM CDT	Severe Thunderstorm Warning	DMX	Marshall	26 min
Apr 18, 7:04 PM CDT	Tornado Warning	DMX	Jasper	56 min
Apr 18, 7:10 PM CDT	Tornado Warning	DMX	Black Hawk	50 min
Apr 18, 7:24 PM CDT	Tornado Warning	DMX	Decatur, Ringgold	51 min
Apr 18, 7:38 PM CDT	Severe Thunderstorm Warning	DMX	Jasper, Marion	52 min
Apr 18, 7:57 PM CDT	Severe Thunderstorm Warning	DMX	Warren	33 min
Apr 18, 8:11 PM CDT	Severe Thunderstorm Warning	DMX	Poweshiek	64 min
Apr 18, 9:10 PM CDT	Severe Thunderstorm Warning	DMX	Mahaska	50 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.