Alert archive / Iowa / Mesoscale Discussions in 2007

Mesoscale Discussion 1917

August 28, 200725 counties in Iowa; 6 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Aug 28, 2007, 7:12 PM CDT for 25 counties in Iowa; 6 counties in Nebraska. It was in force for 63 min.

The area

The outline as issued.

The facts

Issued: Aug 28, 2007, 7:12 PM CDT (00:12 UTC)
Expired: Aug 28, 2007, 8:15 PM CDT
In force: 63 min
Issued by: the Storm Prediction Center

All 31 counties

Adair County, IA, Adams County, IA, Audubon County, IA, Boone County, IA, Carroll County, IA, Cass County, IA, Dallas County, IA, Fremont County, IA, Greene County, IA, Grundy County, IA, Guthrie County, IA, Hardin County, IA, Jasper County, IA, Madison County, IA, Marshall County, IA, Mills County, IA, Montgomery County, IA, Page County, IA, Polk County, IA, Pottawattamie County, IA, Shelby County, IA, Story County, IA, Tama County, IA, Union County, IA, Warren County, IA, Cass County, NE, Douglas County, NE, Lancaster County, NE, Otoe County, NE, Saline County, NE, Sarpy County, NE

The radar

The Des Moines radar (KDMX), 78 km from the middle of the area, began a volume at 00:12 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

Topeka, KS (KFOE), launched 00:00Z, 0.2 hours before the alert went out and 290 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: 64 J/kg
Mixed-layer CIN: -279 J/kg
Mixed-layer LCL: 2707 m above ground
0-6 km bulk shear: 10 kt
0-1 km storm-relative helicity: -19 m²/s²
0-3 km storm-relative helicity: 43 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, 8:17 PM CDT	Mesoscale Discussion	SPC	Adair, Adams, Benton, Cedar, Clinton, Dallas and 19 more	58 min

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.