Alert archive / Wisconsin / Mesoscale Discussions in 2011

Mesoscale Discussion 1659

July 18, 201120 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Jul 18, 2011, 9:06 PM CDT for 20 counties in Wisconsin. It was in force for 54 min.

The area

The outline as issued.

The facts

Issued: Jul 18, 2011, 9:06 PM CDT (02:06 UTC)
Expired: Jul 18, 2011, 10:00 PM CDT
In force: 54 min
Issued by: the Storm Prediction Center

Counties Columbia County, WI, Dane County, WI, Dodge County, WI, Fond du Lac County, WI, Green County, WI, Green Lake County, WI, Iowa County, WI, Jefferson County, WI, Kenosha County, WI, Marquette County, WI, Milwaukee County, WI, Ozaukee County, WI, Racine County, WI, Richland County, WI, Rock County, WI, Sauk County, WI, Sheboygan County, WI, Walworth County, WI, Washington County, WI, Waukesha County, WI

The radar

The Milwaukee radar (KMKX), 71 km from the middle of the area, began a volume at 02:08 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, 2.1 hours before the alert went out and 160 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: 4869 J/kg
Mixed-layer CIN: -4 J/kg
Mixed-layer LCL: 539 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: 4 m²/s²
0-3 km storm-relative helicity: 54 m²/s²
Significant tornado parameter: 0.9
Supercell composite: 4.5

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 19, 9:07 AM CDT	Severe Thunderstorm Watch	SPC	Barron, Buffalo, Burnett, Chippewa, Clark, Dunn and 14 more	6 hr
Jul 19, 11:57 AM CDT	Mesoscale Discussion	SPC	Buffalo, Crawford, La Crosse, Pepin, Pierce, Trempealeau and 1 more	93 min
Jul 19, 1:04 PM CDT	Mesoscale Discussion	SPC	Crawford, Grant, Green, Iowa, La Crosse, Lafayette and 3 more	86 min
Jul 19, 5:28 PM CDT	Mesoscale Discussion	SPC	Barron, Chippewa, Clark, Langlade, Lincoln, Marathon and 14 more	62 min
Jul 19, 5:43 PM CDT	Severe Thunderstorm Watch	SPC	Adams, Barron, Brown, Calumet, Chippewa, Clark and 32 more	7 hr

Nearby

Mesoscale Discussions in Wisconsin, 2011 Every mesoscale discussion in 2011

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.