Alert archive / Iowa / Mesoscale Discussions in 2004

Mesoscale Discussion 1617

July 11, 200412 counties in Iowa; Atchison County, Missouri; 12 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Jul 11, 2004, 2:04 PM CDT for 12 counties in Iowa; Atchison County, Missouri; 12 counties in Nebraska. It was in force for 116 min.

The area

The outline as issued.

The facts

Issued: Jul 11, 2004, 2:04 PM CDT (19:04 UTC)
Expired: Jul 11, 2004, 4:00 PM CDT
In force: 116 min
Issued by: the Storm Prediction Center

All 25 counties

Adams County, IA, Audubon County, IA, Cass County, IA, Fremont County, IA, Harrison County, IA, Mills County, IA, Montgomery County, IA, Page County, IA, Pottawattamie County, IA, Ringgold County, IA, Shelby County, IA, Taylor County, IA, Atchison County, MO, Burt County, NE, Cass County, NE, Dodge County, NE, Douglas County, NE, Johnson County, NE, Lancaster County, NE, Nemaha County, NE, Otoe County, NE, Richardson County, NE, Sarpy County, NE, Saunders County, NE, Washington County, NE

The radar

The Omaha radar (KOAX), 74 km from the middle of the area, began a volume at 19:06 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.

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 7.1 hours before the alert went out and 74 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

The text

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

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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, 11:55 AM CDT	Severe Thunderstorm Watch	SPC	Adair, Adams, Appanoose, Cass, Clarke, Decatur and 16 more	6 hr
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

Mesoscale Discussions in Iowa, 2004 Mesoscale Discussions in Nebraska, 2004 Mesoscale Discussions in Missouri, 2004 Every mesoscale discussion 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.