Alert archive / Minnesota / Mesoscale Discussions in 2007

Mesoscale Discussion 1835

August 21, 20077 counties in Iowa; 23 counties in Minnesota

The Storm Prediction Center issued this mesoscale discussion at Aug 21, 2007, 4:50 PM CDT for 7 counties in Iowa; 23 counties in Minnesota. It was in force for 85 min.

The area

The outline as issued.

The facts

Issued: Aug 21, 2007, 4:50 PM CDT (21:50 UTC)
Expired: Aug 21, 2007, 6:15 PM CDT
In force: 85 min
Issued by: the Storm Prediction Center

All 30 counties

Dickinson County, IA, Emmet County, IA, Howard County, IA, Mitchell County, IA, Osceola County, IA, Winnebago County, IA, Worth County, IA, Blue Earth County, MN, Brown County, MN, Cottonwood County, MN, Dakota County, MN, Dodge County, MN, Faribault County, MN, Fillmore County, MN, Freeborn County, MN, Goodhue County, MN, Jackson County, MN, Le Sueur County, MN, Martin County, MN, Mower County, MN, Nicollet County, MN, Nobles County, MN, Olmsted County, MN, Rice County, MN, Scott County, MN, Steele County, MN, Wabasha County, MN, Waseca County, MN, Watonwan County, MN, Winona County, MN

The radar

The Minneapolis radar (KMPX), 136 km from the middle of the area, began a volume at 21:50 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, 9.8 hours before the alert went out and 319 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: 174 J/kg
Mixed-layer CIN: -479 J/kg
Mixed-layer LCL: 1438 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: 46 m²/s²
0-3 km storm-relative helicity: 61 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 20, 7:03 PM CDT	Mesoscale Discussion	SPC	Adair, Adams, Audubon, Buena Vista, Calhoun, Carroll and 17 more	117 min
Aug 20, 7:35 PM CDT	Mesoscale Discussion	SPC	Adair, Adams, Audubon, Calhoun, Carroll, Cass and 15 more	85 min
Aug 20, 8:10 PM CDT	Severe Thunderstorm Watch	SPC	Adair, Adams, Appanoose, Audubon, Black Hawk, Boone and 50 more	5 hr
Aug 20, 10:06 PM CDT	Mesoscale Discussion	SPC	Adair, Adams, Appanoose, Boone, Buena Vista, Calhoun and 43 more	84 min
Aug 21, 6:17 PM CDT	Mesoscale Discussion	SPC	Buena Vista, Cherokee, Clay, Crawford, Ida, Lyon and 6 more	88 min
Aug 21, 6:47 PM CDT	Tornado Watch	SPC	Audubon, Black Hawk, Boone, Bremer, Buena Vista, Butler and 34 more	7 hr
Aug 20, 10:23 PM CDT	Severe Thunderstorm Watch	SPC	Anoka, Blue Earth, Brown, Carver, Chippewa, Cottonwood and 25 more	5 hr
Aug 21, 2:16 AM CDT	Mesoscale Discussion	SPC	Anoka, Carver, Dakota, Hennepin, Isanti, McLeod and 6 more	59 min

Nearby

Mesoscale Discussions in Minnesota, 2007 Mesoscale Discussions in Iowa, 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.