Alert archive / Minnesota / Mesoscale Discussions in 2007

Mesoscale Discussion 1986

September 20, 200717 counties in Minnesota

The Storm Prediction Center issued this mesoscale discussion at Sep 20, 2007, 3:16 PM CDT for 17 counties in Minnesota. It was in force for 119 min.

The area

The outline as issued.

The facts

Issued: Sep 20, 2007, 3:16 PM CDT (20:16 UTC)
Expired: Sep 20, 2007, 5:15 PM CDT
In force: 119 min
Issued by: the Storm Prediction Center

Counties Blue Earth County, MN, Brown County, MN, Carver County, MN, Chippewa County, MN, Dakota County, MN, Hennepin County, MN, Le Sueur County, MN, Lyon County, MN, McLeod County, MN, Nicollet County, MN, Ramsey County, MN, Redwood County, MN, Renville County, MN, Rice County, MN, Scott County, MN, Sibley County, MN, Yellow Medicine County, MN

The radar

The Minneapolis radar (KMPX), 71 km from the middle of the area, began a volume at 20:16 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.

Tornado Watch 673Sep 20, 3:45 PM CDT

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 8.3 hours before the alert went out and 69 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1024 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: 215 m²/s²
0-3 km storm-relative helicity: 291 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
Sep 20, 3:45 PM CDT	Tornado Watch	SPC	Anoka, Carver, Chippewa, Chisago, Dakota, Goodhue and 18 more	6 hr
Sep 20, 5:37 PM CDT	Severe Thunderstorm Watch	SPC	Chisago, Wabasha	7 hr
Sep 20, 5:54 PM CDT	Mesoscale Discussion	SPC	Clay, Traverse, Wilkin	66 min
Sep 20, 6:48 PM CDT	Mesoscale Discussion	SPC	Anoka, Carver, Chippewa, Chisago, Dakota, Goodhue and 18 more	87 min

Nearby

Mesoscale Discussions in Minnesota, 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.