Alert archive / Wisconsin / Mesoscale Discussions in 2009

Mesoscale Discussion 1689

July 27, 20096 counties in Iowa; 21 counties in Minnesota; 26 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Jul 27, 2009, 2:10 PM CDT for 6 counties in Iowa; 21 counties in Minnesota; 26 counties in Wisconsin. It was in force for 65 min.

The area

The outline as issued.

The facts

Issued: Jul 27, 2009, 2:10 PM CDT (19:10 UTC)
Expired: Jul 27, 2009, 3:15 PM CDT
In force: 65 min
Issued by: the Storm Prediction Center

All 53 counties

Allamakee County, IA, Chickasaw County, IA, Clayton County, IA, Howard County, IA, Mitchell County, IA, Winneshiek County, IA, Blue Earth County, MN, Carver County, MN, Dakota County, MN, Dodge County, MN, Faribault County, MN, Fillmore County, MN, Freeborn County, MN, Goodhue County, MN, Hennepin County, MN, Houston County, MN, Le Sueur County, MN, Mower County, MN, Olmsted County, MN, Ramsey County, MN, Rice County, MN, Scott County, MN, Steele County, MN, Wabasha County, MN, Waseca County, MN, Washington County, MN, Winona County, MN, Adams County, WI, Buffalo County, WI, Chippewa County, WI, Clark County, WI, Columbia County, WI, Crawford County, WI, Dane County, WI, Dunn County, WI, Eau Claire County, WI, Grant County, WI, Green Lake County, WI, Iowa County, WI, Jackson County, WI, Juneau County, WI, La Crosse County, WI, Lafayette County, WI, Marquette County, WI, Monroe County, WI, Pepin County, WI, Pierce County, WI, Richland County, WI, Saint Croix County, WI, Sauk County, WI, Trempealeau County, WI, Vernon County, WI, Wood County, WI

The radar

The La Crosse radar (KARX), 46 km from the middle of the area, began a volume at 19:10 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 629Jul 27, 2:45 PM CDT

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 7.2 hours before the alert went out and 186 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: 231 J/kg
Mixed-layer CIN: -104 J/kg
Mixed-layer LCL: 1259 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 95 m²/s²
0-3 km storm-relative helicity: 174 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.0

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
Jul 27, 2:41 PM CDT	Severe Thunderstorm Watch	SPC	Allamakee, Howard, Mitchell, Winneshiek	6 hr
Jul 27, 6:45 PM CDT	Mesoscale Discussion	SPC	Allamakee, Chickasaw, Howard, Mitchell, Winneshiek	90 min

Nearby

Mesoscale Discussions in Wisconsin, 2009 Mesoscale Discussions in Minnesota, 2009 Mesoscale Discussions in Iowa, 2009 Every mesoscale discussion in 2009

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.