Alert archive / Wisconsin / Mesoscale Discussions in 2012

Mesoscale Discussion 1696

August 4, 201212 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Aug 4, 2012, 1:41 AM CDT for 12 counties in Wisconsin. It was in force for 64 min.

The area

The outline as issued.

The facts

Issued: Aug 4, 2012, 1:41 AM CDT (06:41 UTC)
Expired: Aug 4, 2012, 2:45 AM CDT
In force: 64 min
Issued by: the Storm Prediction Center

Counties Clark County, WI, Iron County, WI, Jackson County, WI, La Crosse County, WI, Lincoln County, WI, Marathon County, WI, Monroe County, WI, Oneida County, WI, Price County, WI, Taylor County, WI, Vilas County, WI, Wood County, WI

The radar

The La Crosse radar (KARX), 155 km from the middle of the area, began a volume at 06:41 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 nearest sounding before it

Green Bay/Straub, WI (KGRB), launched 00:00Z, 6.7 hours before the alert went out and 191 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: 1631 J/kg
Mixed-layer CIN: -21 J/kg
Mixed-layer LCL: 881 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 69 m²/s²
0-3 km storm-relative helicity: 165 m²/s²
Significant tornado parameter: 0.5
Supercell composite: 3.2

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 3, 7:33 PM CDT	Severe Thunderstorm Watch	SPC	Ashland, Bayfield, Burnett, Douglas, Sawyer, Washburn	6 hr
Aug 3, 10:33 PM CDT	Mesoscale Discussion	SPC	Barron, Bayfield, Buffalo, Burnett, Chippewa, Clark and 19 more	87 min
Aug 3, 10:57 PM CDT	Severe Thunderstorm Watch	SPC	Barron, Buffalo, Chippewa, Clark, Dunn, Eau Claire and 8 more	4 hr
Aug 4, 10:26 AM CDT	Mesoscale Discussion	SPC	Grant, Green, Lafayette, Rock, Walworth	49 min
Aug 4, 1:09 PM CDT	Mesoscale Discussion	SPC	Green, Lafayette	66 min
Aug 4, 1:46 PM CDT	Severe Thunderstorm Watch	SPC	Dane, Dodge, Green, Jefferson, Kenosha, Lafayette and 7 more	4 hr

Nearby

Mesoscale Discussions in Wisconsin, 2012 Every mesoscale discussion in 2012

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.