Alert archive / Wisconsin / Mesoscale Discussions in 2011

Mesoscale Discussion 1648

July 18, 20118 counties in Illinois; 31 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Jul 18, 2011, 6:30 AM CDT for 8 counties in Illinois; 31 counties in Wisconsin. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Jul 18, 2011, 6:30 AM CDT (11:30 UTC)
Expired
Jul 18, 2011, 8:30 AM CDT
In force
2 hr
Issued by
the Storm Prediction Center
All 39 counties

Boone County, IL, DeKalb County, IL, Kane County, IL, Lake County, IL, McHenry County, IL, Ogle County, IL, Stephenson County, IL, Winnebago County, IL, Adams County, WI, Clark County, WI, Columbia County, WI, Crawford County, WI, Dane County, WI, Dodge County, WI, Fond du Lac County, WI, Grant County, WI, Green County, WI, Green Lake County, WI, Iowa County, WI, Jackson County, WI, Jefferson County, WI, Juneau County, WI, Kenosha County, WI, La Crosse County, WI, Lafayette County, WI, Marquette County, WI, Monroe County, WI, Portage County, WI, Richland County, WI, Rock County, WI, Sauk County, WI, Trempealeau County, WI, Vernon County, WI, Walworth County, WI, Washington County, WI, Waukesha County, WI, Waushara County, WI, Winnebago County, WI, Wood County, WI

The radar

The Milwaukee radar (KMKX), 111 km from the middle of the area, began a volume at 11:34 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

Green Bay/Straub, WI (KGRB), launched 00:00Z, 11.5 hours before the alert went out and 177 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, Green Bay/Straub, WI at 00:00Z on 2011-07-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3989 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, Green Bay/Straub, WI at 00:00Z on 2011-07-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 70 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
3989 J/kg
Mixed-layer CIN
-33 J/kg
Mixed-layer LCL
1231 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
70 m²/s²
0-3 km storm-relative helicity
142 m²/s²
Significant tornado parameter
2.2
Supercell composite
17.3

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
Jul 17, 7:22 PM CDTSevere Thunderstorm WatchSPCBrown, Calumet, Door, Florence, Forest, Kewaunee and 17 more4 hr
Jul 17, 9:24 PM CDTMesoscale DiscussionSPCDoor, Florence, Forest, Kewaunee, Langlade, Lincoln and 9 more66 min
Jul 17, 11:06 PM CDTMesoscale DiscussionSPCCalumet, Fond du Lac, Kewaunee, Manitowoc, Sheboygan54 min
Jul 18, 8:05 AM CDTSevere Thunderstorm WatchSPCAdams, Brown, Buffalo, Calumet, Clark, Columbia and 32 more4 hr
Jul 18, 9:54 AM CDTMesoscale DiscussionSPCManitowoc, Sheboygan96 min
Jul 18, 2:06 PM CDTMesoscale DiscussionSPCBarron, Brown, Chippewa, Clark, Dunn, Eau Claire and 17 more84 min
Jul 18, 2:26 PM CDTSevere Thunderstorm WatchSPCAdams, Brown, Calumet, Chippewa, Clark, Door and 28 more7 hr
Jul 18, 5:42 PM CDTMesoscale DiscussionSPCAdams, Brown, Calumet, Chippewa, Clark, Eau Claire and 21 more63 min
Jul 18, 6:18 PM CDTSevere Thunderstorm WatchSPCColumbia, Dane, Dodge, Fond du Lac, Green, Green Lake and 14 more3 hr

Nearby

Mesoscale Discussions in Wisconsin, 2011Mesoscale Discussions in Illinois, 2011Every 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.