Alert archive / Iowa / Mesoscale Discussions in 2004
Mesoscale Discussion 377
The Storm Prediction Center issued this mesoscale discussion at Apr 18, 2004, 7:05 PM CDT for 4 states. It was in force for 115 min.
The area
The outline as issued.
The facts
- Issued
- Apr 18, 2004, 7:05 PM CDT (00:05 UTC)
- Expired
- Apr 18, 2004, 9:00 PM CDT
- In force
- 115 min
- Issued by
- the Storm Prediction Center
All 82 counties
Audubon County, IA, Buena Vista County, IA, Calhoun County, IA, Carroll County, IA, Cass County, IA, Cherokee County, IA, Clay County, IA, Crawford County, IA, Dickinson County, IA, Emmet County, IA, Fremont County, IA, Greene County, IA, Hancock County, IA, Harrison County, IA, Humboldt County, IA, Ida County, IA, Kossuth County, IA, Lyon County, IA, Mills County, IA, Monona County, IA, Montgomery County, IA, O'Brien County, IA, Osceola County, IA, Palo Alto County, IA, Plymouth County, IA, Pocahontas County, IA, Pottawattamie County, IA, Sac County, IA, Shelby County, IA, Sioux County, IA, Webster County, IA, Winnebago County, IA, Woodbury County, IA, Worth County, IA, Wright County, IA, Blue Earth County, MN, Cottonwood County, MN, Dodge County, MN, Faribault County, MN, Freeborn County, MN, Jackson County, MN, Martin County, MN, Murray County, MN, Nobles County, MN, Steele County, MN, Waseca County, MN, Watonwan County, MN, Adams County, NE, Burt County, NE, Butler County, NE, Cass County, NE, Clay County, NE, Colfax County, NE, Cuming County, NE, Dakota County, NE, Dixon County, NE, Dodge County, NE, Douglas County, NE, Fillmore County, NE, Gage County, NE, Hamilton County, NE, Jefferson County, NE, Johnson County, NE, Lancaster County, NE, Nemaha County, NE, Nuckolls County, NE, Otoe County, NE, Pawnee County, NE, Platte County, NE, Polk County, NE, Saline County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE, Stanton County, NE, Thayer County, NE, Thurston County, NE, Washington County, NE, Wayne County, NE, Webster County, NE, York County, NE, Union County, SD
The radar
The Omaha radar (KOAX), 63 km from the middle of the area, began a volume at 00:08 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 watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Omaha, NE (KOAX), launched 00:00Z, 0.1 hours before the alert went out and 63 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.
- Mixed-layer CAPE
- 1099 J/kg
- Mixed-layer CIN
- -135 J/kg
- Mixed-layer LCL
- 1062 m above ground
- 0-6 km bulk shear
- 64 kt
- 0-1 km storm-relative helicity
- 334 m²/s²
- 0-3 km storm-relative helicity
- 385 m²/s²
- Significant tornado parameter
- 1.2
- Supercell composite
- 5.0
The text
As transmitted, in the capitals the NWS used until 2016.
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</html>SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 18, 9:45 PM CDT | Tornado Watch | SPC | Adair, Adams, Allamakee, Audubon, Benton, Black Hawk and 49 more | 4 hr |
| Apr 18, 11:12 PM CDT | Mesoscale Discussion | SPC | Adair, Adams, Allamakee, Audubon, Benton, Black Hawk and 48 more | 93 min |
| Apr 18, 7:10 PM CDT | Mesoscale Discussion | SPC | Lincoln, Pipestone, Rock | 65 min |
| Apr 18, 8:28 PM CDT | Mesoscale Discussion | SPC | Brown, Carver, Dakota, Goodhue, Hennepin, Le Sueur and 7 more | 92 min |
Nearby
Mesoscale Discussions in Iowa, 2004Mesoscale Discussions in Nebraska, 2004Mesoscale Discussions in Minnesota, 2004Every 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.