Alert archive / Iowa / Tornado Warnings in 2003

Tornado Warning 45, NWS Sioux Falls, SD

July 20, 2003Woodbury County, Iowa

NWS Sioux Falls, SD issued this tornado warning at Jul 20, 2003, 6:21 PM CDT for Woodbury County, Iowa. It was in force for 39 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Jul 20, 2003, 6:21 PM CDT (23:21 UTC)
Expired: Jul 20, 2003, 7:00 PM CDT
In force: 39 min
Issued by: NWS Sioux Falls, SD
Area: Counties, with a storm outline in the text

County Woodbury County, IA

The radar

The Omaha radar (KOAX), 126 km from the middle of the area, began a volume at 23:22 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.

The watch it was issued in

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

Issued	Product	Office	Lasted
Jul 20, 2:50 PM CDT	Tornado Watch	SPC	6 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 11.4 hours before the alert went out and 126 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: 1371 J/kg
Mixed-layer CIN: -314 J/kg
Mixed-layer LCL: 1243 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 67 m²/s²
0-3 km storm-relative helicity: 88 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.4

Open this sounding in Storm Lab

The text

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

728 
WFUS53 KFSD 202321
TORFSD
IAC193-210000-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
621 PM CDT SUN JUL 20 2003

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* TORNADO WARNING FOR...
  WOODBURY COUNTY IN NORTHWEST IOWA

* UNTIL 700 PM CDT

* AT 621 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  THUNDERSTORM WITH A DEVELOPING TORNADO 6 MILES NORTHWEST OF
  MOVILLE...MOVING SOUTH AT 30 MPH.

* SOME LOCATIONS AFFECTED...
  SLOAN AROUND 655 PM CDT

IN ADDITION TO THE THREAT OF A TORNADO...DAMAGING HAIL AND STRONG
WINDS CAN BE EXPECTED. GO TO A SAFE PLACE NOW.

IF YOU ARE IN THE PATH OF THIS STORM...TAKE COVER IMMEDIATELY.

LAT...LON 4256 9594 4256 9627 4222 9624 4223 9585

$$

BOUSTEAD

The office that day

Everything else NWS Sioux Falls, SD issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 20, 9:22 AM CDT	Severe Thunderstorm Warning	FSD	O'Brien	38 min
Jul 20, 9:41 AM CDT	Severe Thunderstorm Warning	FSD	O'Brien, Sioux	34 min
Jul 20, 10:08 AM CDT	Severe Thunderstorm Warning	FSD	Cherokee, O'Brien, Plymouth, Sioux	22 min
Jul 20, 10:09 AM CDT	Severe Thunderstorm Warning	FSD	Cherokee, Plymouth	36 min
Jul 20, 10:29 AM CDT	Severe Thunderstorm Warning	FSD	Buena Vista, Cherokee	31 min
Jul 20, 11:00 AM CDT	Severe Thunderstorm Warning	FSD	Buena Vista	30 min
Jul 20, 11:57 AM CDT	Severe Thunderstorm Warning	FSD	Lyon, Osceola	33 min
Jul 20, 5:36 PM CDT	Severe Thunderstorm Warning	FSD	Plymouth	39 min
Jul 20, 6:09 PM CDT	Severe Thunderstorm Warning	FSD	Woodbury	51 min
Jul 20, 6:15 PM CDT	Severe Thunderstorm Warning	FSD	Plymouth	30 min
Jul 20, 6:36 PM CDT	Severe Thunderstorm Warning	FSD	Buena Vista	39 min
Jul 20, 6:58 PM CDT	Tornado Warning	FSD	Woodbury	32 min

Nearby

Tornado Warnings in Iowa, 2003 Every tornado warning in 2003 Tornadoes in 2003

Sources

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