Alert archive / Iowa / Tornado Warnings in 2004

Tornado Warning 1, NWS Des Moines, IA

April 17, 2004Cerro Gordo County, Worth County, Iowa

NWS Des Moines, IA issued this tornado warning at Apr 17, 2004, 9:37 PM CDT for Cerro Gordo County, Worth County, Iowa. It was in force for 38 min. 4 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 17, 2004, 9:37 PM CDT (02:37 UTC)
Expired: Apr 17, 2004, 10:15 PM CDT
In force: 38 min
Issued by: NWS Des Moines, IA
Area: Counties, with a storm outline in the text

Counties Cerro Gordo County, IA, Worth County, IA

The radar

The Minneapolis radar (KMPX), 176 km from the middle of the area, began a volume at 02:39 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 17, 9:40 PM CDT	TORNADO	3 E Mason City, IA	PUBLIC REPORT VIA KIMT TELEVISION.
Apr 17, 9:50 PM CDT	HAIL 0.88	2 E Kensett, IA
Apr 17, 9:54 PM CDT	HAIL 1.25	Rock Falls, IA
Apr 17, 9:55 PM CDT	HAIL 1.25	Rock Falls, IA

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

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 17, 7:45 PM CDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Minneapolis, MN (KMPX), launched 00:00Z, 2.6 hours before the alert went out and 177 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: 2026 m above ground
0-6 km bulk shear: 65 kt
0-1 km storm-relative helicity: 91 m²/s²
0-3 km storm-relative helicity: 489 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

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

137 
WFUS53 KDMX 180237
TORDMX
IAC033-195-180315-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
937 PM CDT SAT APR 17 2004

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* TORNADO WARNING FOR...
  CERRO GORDO COUNTY IN NORTH CENTRAL IOWA
  THIS INCLUDES THE CITY OF MASON CITY
  WORTH COUNTY IN NORTH CENTRAL IOWA

* UNTIL 1015 PM CDT

* AT 930 PM...RADAR INDICATED A THUNDERSTORM CAPABLE OF PRODUCING A
  TORNADO 5 MILES NORTHWEST OF MASON CITY...MOVING EAST AT 30 MPH.

* THE STORM WILL BE...

  4 MILES SOUTH OF PLYMOUTH AROUND 940 PM AND
  NEAR ROCK FALLS AROUND 945 PM.

THERE ARE TWO ROTATIONS WITH THIS STORM. ONE EAST OF JOICE AND 
ANOTHER MOVING TOWARD MASON CITY. TAKE SHELTER NOW.

THIS IS A HAZARDOUS SITUATION. SEEK SHELTER IN A BASEMENT...OR IN AN
INTERIOR ROOM. STAY AWAY FROM WINDOWS. IF YOU ARE OUTSIDE OR IN A
CAR...SEEK SHELTER IN A REINFORCED BUILDING.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 100 AM SUNDAY
MORNING FOR NORTHWESTERN IOWA.

LAT...LON 4345 9339 4308 9348 4296 9304 4346 9304

DONAVON

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 17, 7:46 PM CDT	Severe Thunderstorm Warning	DMX	Kossuth, Winnebago	44 min
Apr 17, 8:32 PM CDT	Severe Thunderstorm Warning	DMX	Winnebago	28 min
Apr 17, 8:52 PM CDT	Severe Thunderstorm Warning	DMX	Worth	38 min
Apr 17, 9:11 PM CDT	Severe Thunderstorm Warning	DMX	Cerro Gordo	34 min
Apr 17, 9:29 PM CDT	Severe Thunderstorm Warning	DMX	Worth	31 min
Apr 17, 9:31 PM CDT	Severe Thunderstorm Warning	DMX	Pocahontas	14 min
Apr 17, 9:43 PM CDT	Severe Thunderstorm Warning	DMX	Kossuth, Palo Alto	32 min
Apr 17, 9:46 PM CDT	Severe Thunderstorm Warning	DMX	Pocahontas	29 min
Apr 17, 10:13 PM CDT	Severe Thunderstorm Warning	DMX	Worth	47 min
Apr 17, 10:25 PM CDT	Severe Thunderstorm Warning	DMX	Winnebago	65 min
Apr 17, 10:31 PM CDT	Severe Thunderstorm Warning	DMX	Kossuth	44 min
Apr 17, 10:33 PM CDT	Tornado Warning	DMX	Worth	27 min
Apr 17, 11:01 PM CDT	Tornado Warning	DMX	Worth	29 min

Nearby

Tornado Warnings in Iowa, 2004 Every tornado warning in 2004 Tornadoes in 2004

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.