Alert archive / Iowa / Mesoscale Discussions in 2016

Mesoscale Discussion 1650

September 6, 201632 counties in Iowa; 11 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Sep 6, 2016, 3:47 PM CDT for 32 counties in Iowa; 11 counties in Nebraska. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Sep 6, 2016, 3:47 PM CDT (20:47 UTC)
Expired: Sep 6, 2016, 6:15 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 40%

All 43 counties

Audubon County, IA, Bremer County, IA, Buena Vista County, IA, Butler County, IA, Calhoun County, IA, Carroll County, IA, Cerro Gordo County, IA, Chickasaw County, IA, Crawford County, IA, Fayette County, IA, Floyd County, IA, Franklin County, IA, Greene County, IA, Hamilton County, IA, Hancock County, IA, Hardin County, IA, Harrison County, IA, Howard County, IA, Humboldt County, IA, Ida County, IA, Kossuth County, IA, Mitchell County, IA, Monona County, IA, Palo Alto County, IA, Pocahontas County, IA, Sac County, IA, Shelby County, IA, Webster County, IA, Winnebago County, IA, Woodbury County, IA, Worth County, IA, Wright County, IA, Burt County, NE, Butler County, NE, Colfax County, NE, Cuming County, NE, Dodge County, NE, Douglas County, NE, Platte County, NE, Sarpy County, NE, Saunders County, NE, Thurston County, NE, Washington County, NE

The radar

The Des Moines radar (KDMX), 97 km from the middle of the area, began a volume at 20:51 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

Davenport, (KDVN), launched 12:00Z, 8.8 hours before the alert went out and 352 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: 844 J/kg
Mixed-layer CIN: -79 J/kg
Mixed-layer LCL: 1129 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 127 m²/s²
0-3 km storm-relative helicity: 152 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 1.5

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 6, 2:22 PM CDT	Mesoscale Discussion	SPC	Howard, Mitchell	2 hr
Sep 6, 5:18 PM CDT	Severe Thunderstorm Watch	SPC	Allamakee, Chickasaw, Floyd, Howard, Mitchell, Winneshiek	4 hr
Sep 5, 7:37 PM CDT	Severe Thunderstorm Watch	SPC	Antelope, Blaine, Boone, Boyd, Buffalo, Cedar and 27 more	7 hr
Sep 5, 11:31 PM CDT	Mesoscale Discussion	SPC	Antelope, Blaine, Custer, Garfield, Greeley, Holt and 6 more	29 min
Sep 6, 3:00 PM CDT	Mesoscale Discussion	SPC	Franklin, Webster	3 hr

Nearby

Mesoscale Discussions in Iowa, 2016 Mesoscale Discussions in Nebraska, 2016 Every mesoscale discussion in 2016

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.