Alert archive / Wisconsin / Mesoscale Discussions in 2004

Mesoscale Discussion 668

May 12, 200418 counties in Iowa; 12 counties in Minnesota; 20 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at May 12, 2004, 11:29 AM CDT for 18 counties in Iowa; 12 counties in Minnesota; 20 counties in Wisconsin. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
May 12, 2004, 11:29 AM CDT (16:29 UTC)
Expired
May 12, 2004, 1:30 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
All 50 counties

Allamakee County, IA, Black Hawk County, IA, Bremer County, IA, Buchanan County, IA, Butler County, IA, Cerro Gordo County, IA, Chickasaw County, IA, Clayton County, IA, Delaware County, IA, Fayette County, IA, Floyd County, IA, Franklin County, IA, Grundy County, IA, Hardin County, IA, Howard County, IA, Mitchell County, IA, Winneshiek County, IA, Worth County, IA, Dakota County, MN, Dodge County, MN, Fillmore County, MN, Freeborn County, MN, Goodhue County, MN, Houston County, MN, Mower County, MN, Olmsted County, MN, Steele County, MN, Wabasha County, MN, Washington County, MN, Winona County, MN, Barron County, WI, Buffalo County, WI, Chippewa County, WI, Clark County, WI, Crawford County, WI, Dunn County, WI, Eau Claire County, WI, Jackson County, WI, La Crosse County, WI, Monroe County, WI, Pepin County, WI, Pierce County, WI, Polk County, WI, Rusk County, WI, Saint Croix County, WI, Sawyer County, WI, Taylor County, WI, Trempealeau County, WI, Vernon County, WI, Washburn County, WI

The radar

The La Crosse radar (KARX), 79 km from the middle of the area, began a volume at 16:30 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.

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 4.5 hours before the alert went out and 147 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-pSkew-T log-p diagram, Minneapolis, MN at 12:00Z on 2004-05-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 503 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Minneapolis, MN at 12:00Z on 2004-05-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 295 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
503 J/kg
Mixed-layer CIN
-149 J/kg
Mixed-layer LCL
858 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
295 m²/s²
0-3 km storm-relative helicity
278 m²/s²
Significant tornado parameter
0.2
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.

IssuedProductOfficeCountiesLasted
May 12, 12:20 PM CDTSevere Thunderstorm WatchSPCAllamakee, Cerro Gordo, Chickasaw, Clayton, Fayette, Floyd and 5 more6 hr
May 12, 2:22 PM CDTMesoscale DiscussionSPCAllamakee, Bremer, Butler, Cerro Gordo, Chickasaw, Clayton and 8 more83 min
May 12, 3:37 PM CDTMesoscale DiscussionSPCAllamakee, Bremer, Butler, Cerro Gordo, Chickasaw, Clayton and 10 more83 min
May 12, 5:22 PM CDTMesoscale DiscussionSPCAllamakee, Clayton, Fayette53 min
May 11, 7:00 PM CDTTornado WatchSPCBecker, Beltrami, Clay, Clearwater, Hubbard, Mahnomen and 4 more6 hr
May 11, 7:22 PM CDTMesoscale DiscussionSPCBecker, Beltrami, Cass, Clearwater, Hubbard, Mahnomen113 min
May 11, 8:45 PM CDTSevere Thunderstorm WatchSPCBecker, Beltrami, Big Stone, Cass, Clay, Clearwater and 15 more5 hr
May 11, 10:08 PM CDTMesoscale DiscussionSPCBig Stone, Grant, Lac qui Parle, Lincoln, Lyon, Otter Tail and 6 more2 hr

Nearby

Mesoscale Discussions in Wisconsin, 2004Mesoscale Discussions in Iowa, 2004Mesoscale Discussions in Minnesota, 2004Every mesoscale discussion in 2004

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.