Alert archive / Iowa / Severe Thunderstorm Watches in 2004

Severe Thunderstorm Watch 603

July 11, 200422 counties in Iowa; 11 counties in Missouri; 9 counties in Nebraska

The Storm Prediction Center issued this severe thunderstorm watch at Jul 11, 2004, 11:55 AM CDT for 22 counties in Iowa; 11 counties in Missouri; 9 counties in Nebraska. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued: Jul 11, 2004, 11:55 AM CDT (16:55 UTC)
Expired: Jul 11, 2004, 6:00 PM CDT
In force: 6 hr
Issued by: the Storm Prediction Center

All 42 counties

Adair County, IA, Adams County, IA, Appanoose County, IA, Cass County, IA, Clarke County, IA, Decatur County, IA, Fremont County, IA, Jasper County, IA, Lucas County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Mills County, IA, Monroe County, IA, Montgomery County, IA, Page County, IA, Pottawattamie County, IA, Ringgold County, IA, Taylor County, IA, Union County, IA, Warren County, IA, Wayne County, IA, Adair County, MO, Atchison County, MO, Gentry County, MO, Grundy County, MO, Harrison County, MO, Holt County, MO, Mercer County, MO, Nodaway County, MO, Putnam County, MO, Sullivan County, MO, Worth County, MO, Cass County, NE, Douglas County, NE, Johnson County, NE, Nemaha County, NE, Otoe County, NE, Pawnee County, NE, Richardson County, NE, Sarpy County, NE, Washington County, NE

The radar

The Omaha radar (KOAX), 125 km from the middle of the area, began a volume at 16:57 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.

Warnings issued inside it

11 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Jul 11, 12:10 PM CDT	Severe Thunderstorm Warning	DMX	Adair, Madison	50 min
Jul 11, 12:49 PM CDT	Severe Thunderstorm Warning	DMX	Mahaska, Wapello	41 min
Jul 11, 1:11 PM CDT	Severe Thunderstorm Warning	DMX	Madison	19 min
Jul 11, 1:19 PM CDT	Severe Thunderstorm Warning	DMX	Warren	56 min
Jul 11, 1:51 PM CDT	Severe Thunderstorm Warning	DMX	Clarke, Lucas	54 min
Jul 11, 2:10 PM CDT	Severe Thunderstorm Warning	OAX	Richardson	35 min
Jul 11, 2:42 PM CDT	Severe Thunderstorm Warning	EAX	Atchison, Holt, Nodaway	63 min
Jul 11, 3:47 PM CDT	Severe Thunderstorm Warning	DMX	Decatur	43 min
Jul 11, 4:49 PM CDT	Severe Thunderstorm Warning	EAX	Holt	41 min
Jul 11, 5:28 PM CDT	Flash Flood Warning	DMX	Wayne	6 hr
Jul 11, 5:44 PM CDT	Severe Thunderstorm Warning	OAX	Richardson	31 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 4.9 hours before the alert went out and 125 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: 3561 J/kg
Mixed-layer CIN: -77 J/kg
Mixed-layer LCL: 820 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: 131 m²/s²
0-3 km storm-relative helicity: 133 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 3.2

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 11, 10:14 AM CDT	Mesoscale Discussion	SPC	Cedar, Clinton, Des Moines, Henry, Jackson, Jefferson and 8 more	91 min
Jul 11, 10:33 AM CDT	Mesoscale Discussion	SPC	Adams, Audubon, Cass, Fremont, Harrison, Mills and 6 more	117 min
Jul 11, 11:40 AM CDT	Severe Thunderstorm Watch	SPC	Benton, Buchanan, Cedar, Clinton, Delaware, Des Moines and 14 more	6 hr
Jul 11, 2:04 PM CDT	Mesoscale Discussion	SPC	Adams, Audubon, Cass, Fremont, Harrison, Mills and 6 more	116 min
Jul 11, 3:00 PM CDT	Severe Thunderstorm Watch	SPC	Audrain, Boone, Caldwell, Carroll, Chariton, Grundy and 17 more	5 hr
Jul 11, 5:19 PM CDT	Mesoscale Discussion	SPC	Adair, Audrain, Boone, Buchanan, Caldwell, Callaway and 28 more	116 min
Jul 10, 9:41 PM CDT	Mesoscale Discussion	SPC	Chase, Dundy, Frontier, Furnas, Harlan, Hayes and 2 more	3 hr
Jul 11, 2:58 PM CDT	Mesoscale Discussion	SPC	Arthur, Box Butte, Cherry, Cheyenne, Dawes, Deuel and 6 more	2 hr

Nearby

Severe Thunderstorm Watches in Iowa, 2004 Severe Thunderstorm Watches in Missouri, 2004 Severe Thunderstorm Watches in Nebraska, 2004 Every severe thunderstorm watch 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.