Alert archive / Iowa / Mesoscale Discussions in 2011

Mesoscale Discussion 2093

September 2, 201116 counties in Iowa; 4 counties in Minnesota

The Storm Prediction Center issued this mesoscale discussion at Sep 2, 2011, 3:27 AM CDT for 16 counties in Iowa; 4 counties in Minnesota. It was in force for 93 min.

The area

The outline as issued.

The facts

Issued: Sep 2, 2011, 3:27 AM CDT (08:27 UTC)
Expired: Sep 2, 2011, 5:00 AM CDT
In force: 93 min
Issued by: the Storm Prediction Center

Counties Buena Vista County, IA, Cerro Gordo County, IA, Clay County, IA, Emmet County, IA, Floyd County, IA, Hancock County, IA, Howard County, IA, Humboldt County, IA, Kossuth County, IA, Mitchell County, IA, O'Brien County, IA, Palo Alto County, IA, Pocahontas County, IA, Winnebago County, IA, Winneshiek County, IA, Worth County, IA, Faribault County, MN, Fillmore County, MN, Freeborn County, MN, Mower County, MN

The radar

The Minneapolis radar (KMPX), 172 km from the middle of the area, began a volume at 08:30 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.

Severe Thunderstorm Watch 821Sep 2, 3:50 AM CDT

The nearest sounding before it

Minneapolis, MN (KMPX), launched 00:00Z, 8.5 hours before the alert went out and 171 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: -349 J/kg
Mixed-layer LCL: 1469 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: 124 m²/s²
0-3 km storm-relative helicity: 169 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.4

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
Sep 2, 3:48 AM CDT	Severe Thunderstorm Watch	SPC	Allamakee, Bremer, Butler, Cerro Gordo, Chickasaw, Clayton and 15 more	6 hr
Sep 2, 2:41 PM CDT	Mesoscale Discussion	SPC	Adair, Adams, Allamakee, Audubon, Benton, Black Hawk and 66 more	94 min
Sep 1, 8:57 PM CDT	Mesoscale Discussion	SPC	Aitkin, Benton, Carlton, Cass, Crow Wing, Isanti and 8 more	93 min

Nearby

Mesoscale Discussions in Iowa, 2011 Mesoscale Discussions in Minnesota, 2011 Every mesoscale discussion in 2011

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.