Alert archive / Iowa / Severe Thunderstorm Warnings in 2004

Severe Thunderstorm Warning 366, NWS Sioux Falls, SD

July 12, 2004Plymouth County, Iowa

NWS Sioux Falls, SD issued this severe thunderstorm warning at Jul 12, 2004, 11:32 PM CDT for Plymouth County, Iowa. It was in force for 28 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: Jul 12, 2004, 11:32 PM CDT (04:32 UTC)
Expired: Jul 13, 2004, 12:00 AM CDT
In force: 28 min
Issued by: NWS Sioux Falls, SD
Area: Counties, with a storm outline in the text

County Plymouth County, IA

The radar

The Sioux Falls radar (KFSD), 103 km from the middle of the area, began a volume at 04:32 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
Jul 12, 11:35 PM CDT	HAIL 0.88	1 N Le Mars, IA
Jul 13, 12:00 AM CDT	HAIL 1.25	Remsen, 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
Jul 12, 6:20 PM CDT	Tornado Watch	SPC	7 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 4.5 hours before the alert went out and 163 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: 4686 J/kg
Mixed-layer CIN: -62 J/kg
Mixed-layer LCL: 1125 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 101 m²/s²
0-3 km storm-relative helicity: 194 m²/s²
Significant tornado parameter: 3.2
Supercell composite: 20.9

Open this sounding in Storm Lab

The text

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

000 
WUUS53 KFSD 130432
SVRFSD
IAC149-130500-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1131 PM CDT MON JUL 12 2004

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  PLYMOUTH COUNTY IN NORTHWEST IOWA

* UNTIL MIDNIGHT CDT

* AT 1127 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL.  
  THIS STORM WAS 5 MILES WEST OF LE MARS...MOVING EAST AT 30 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  REMSEN AROUND 1150 PM CDT

SEVERE THUNDERSTORMS CAN PRODUCE TORNADOES WITH LITTLE OR NO ADVANCE
WARNING. PREPARE TO MOVE TO A PLACE OF SAFETY IN A STURDY STRUCTURE
SUCH AS A BASEMENT OR SMALL INTERIOR ROOM IF A TORNADO IS SPOTTED.

THIS STORM WILL PRODUCE LARGE HAIL. GO INSIDE A STURDY BUILDING AND
STAY AWAY FROM WINDOWS.

LAT...LON 4285 9627 4275 9632 4262 9588 4281 9587

$$

SCHUMACHER

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 12, 11:29 PM CDT	Severe Thunderstorm Warning	FSD	O'Brien	31 min
Jul 12, 11:59 PM CDT	Severe Thunderstorm Warning	FSD	Cherokee, Plymouth	31 min
Jul 13, 12:01 AM CDT	Severe Thunderstorm Warning	FSD	O'Brien	29 min
Jul 13, 12:08 AM CDT	Severe Thunderstorm Warning	FSD	Sioux	22 min
Jul 13, 12:23 AM CDT	Severe Thunderstorm Warning	FSD	Lyon	37 min
Jul 13, 12:27 AM CDT	Severe Thunderstorm Warning	FSD	O'Brien	48 min
Jul 13, 12:40 AM CDT	Severe Thunderstorm Warning	FSD	Cherokee	35 min
Jul 13, 12:46 AM CDT	Severe Thunderstorm Warning	FSD	Lyon	44 min
Jul 13, 12:58 AM CDT	Severe Thunderstorm Warning	FSD	Buena Vista, Clay	62 min
Jul 13, 1:04 AM CDT	Severe Thunderstorm Warning	FSD	Sioux	41 min
Jul 13, 1:05 AM CDT	Severe Thunderstorm Warning	FSD	Osceola	25 min
Jul 13, 1:13 AM CDT	Severe Thunderstorm Warning	FSD	O'Brien	62 min
Jul 13, 1:17 AM CDT	Flash Flood Warning	FSD	O'Brien	88 min
Jul 13, 1:45 AM CDT	Severe Thunderstorm Warning	FSD	Sioux	30 min
Jul 13, 1:51 AM CDT	Severe Thunderstorm Warning	FSD	Cherokee	39 min
Jul 13, 1:58 AM CDT	Severe Thunderstorm Warning	FSD	Buena Vista, Clay	47 min
Jul 13, 2:31 AM CDT	Severe Thunderstorm Warning	FSD	O'Brien	44 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2004 Every severe thunderstorm warning 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.