Alert archive / Iowa / Mesoscale Discussions in 2007

Mesoscale Discussion 1914

August 28, 200728 counties in Iowa; 22 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Aug 28, 2007, 4:06 PM CDT for 28 counties in Iowa; 22 counties in Nebraska. It was in force for 54 min.

The area

The outline as issued.

The facts

Issued: Aug 28, 2007, 4:06 PM CDT (21:06 UTC)
Expired: Aug 28, 2007, 5:00 PM CDT
In force: 54 min
Issued by: the Storm Prediction Center

All 50 counties

Audubon County, IA, Boone County, IA, Butler County, IA, Calhoun County, IA, Carroll County, IA, Cerro Gordo County, IA, Chickasaw County, IA, Crawford County, IA, Floyd County, IA, Franklin County, IA, Greene County, IA, Guthrie County, IA, Hamilton County, IA, Hancock County, IA, Hardin County, IA, Harrison County, IA, Humboldt County, IA, Ida County, IA, Mills County, IA, Mitchell County, IA, Monona County, IA, Pocahontas County, IA, Pottawattamie County, IA, Sac County, IA, Shelby County, IA, Webster County, IA, Worth County, IA, Wright County, IA, Adams County, NE, Burt County, NE, Butler County, NE, Cass County, NE, Clay County, NE, Colfax County, NE, Dodge County, NE, Douglas County, NE, Fillmore County, NE, Franklin County, NE, Hamilton County, NE, Lancaster County, NE, Nuckolls County, NE, Polk County, NE, Saline County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE, Thayer County, NE, Washington County, NE, Webster County, NE, York County, NE

The radar

The Omaha radar (KOAX), 91 km from the middle of the area, began a volume at 21:09 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 12:00Z, 9.1 hours before the alert went out and 91 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: 438 J/kg
Mixed-layer CIN: -240 J/kg
Mixed-layer LCL: 1545 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 15 m²/s²
0-3 km storm-relative helicity: 92 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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
Aug 28, 3:24 PM CDT	Mesoscale Discussion	SPC	Allamakee, Bremer, Butler, Cerro Gordo, Chickasaw, Emmet and 14 more	66 min
Aug 28, 5:30 PM CDT	Severe Thunderstorm Watch	SPC	Audubon, Boone, Calhoun, Carroll, Cerro Gordo, Crawford and 17 more	5 hr
Aug 28, 6:04 PM CDT	Mesoscale Discussion	SPC	Adair, Allamakee, Audubon, Black Hawk, Boone, Bremer and 23 more	3 hr

Nearby

Mesoscale Discussions in Iowa, 2007 Mesoscale Discussions in Nebraska, 2007 Every mesoscale discussion in 2007

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.