Alert archive / Iowa / Mesoscale Discussions in 2007

Mesoscale Discussion 1490

July 15, 20074 counties in Iowa; 4 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Jul 15, 2007, 9:37 PM CDT for 4 counties in Iowa; 4 counties in Nebraska. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued: Jul 15, 2007, 9:37 PM CDT (02:37 UTC)
Expired: Jul 15, 2007, 11:00 PM CDT
In force: 83 min
Issued by: the Storm Prediction Center

Counties Harrison County, IA, Mills County, IA, Montgomery County, IA, Pottawattamie County, IA, Cass County, NE, Douglas County, NE, Sarpy County, NE, Washington County, NE

The radar

The Omaha radar (KOAX), 48 km from the middle of the area, began a volume at 02:40 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 00:00Z, 2.6 hours before the alert went out and 48 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: 2071 J/kg
Mixed-layer CIN: -18 J/kg
Mixed-layer LCL: 1841 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 31 m²/s²
0-3 km storm-relative helicity: 167 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 6.4

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 16, 1:36 PM CDT	Mesoscale Discussion	SPC	Buena Vista, Cerro Gordo, Clay, Dickinson, Emmet, Franklin and 13 more	114 min
Jul 16, 2:07 PM CDT	Tornado Watch	SPC	Black Hawk, Bremer, Buena Vista, Butler, Calhoun, Cerro Gordo and 28 more	8 hr
Jul 16, 3:11 PM CDT	Mesoscale Discussion	SPC	Benton, Black Hawk, Bremer, Buchanan, Clayton, Delaware and 12 more	2 hr
Jul 16, 3:38 PM CDT	Tornado Watch	SPC	Appanoose, Benton, Boone, Buchanan, Cedar, Clarke and 39 more	7 hr
Jul 16, 5:24 PM CDT	Mesoscale Discussion	SPC	Benton, Black Hawk, Boone, Bremer, Buchanan, Butler and 47 more	2 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.