Alert archive / Iowa / Mesoscale Discussions in 2011

Mesoscale Discussion 1833

August 2, 20114 states

The Storm Prediction Center issued this mesoscale discussion at Aug 2, 2011, 12:57 PM CDT for 4 states. It was in force for 93 min.

The area

The outline as issued.

The facts

Issued: Aug 2, 2011, 12:57 PM CDT (17:57 UTC)
Expired: Aug 2, 2011, 2:30 PM CDT
In force: 93 min
Issued by: the Storm Prediction Center

All 101 counties

Allamakee County, IA, Benton County, IA, Black Hawk County, IA, Bremer County, IA, Buchanan County, IA, Butler County, IA, Cedar County, IA, Chickasaw County, IA, Clayton County, IA, Clinton County, IA, Delaware County, IA, Des Moines County, IA, Dubuque County, IA, Fayette County, IA, Floyd County, IA, Franklin County, IA, Grundy County, IA, Hardin County, IA, Henry County, IA, Iowa County, IA, Jackson County, IA, Jasper County, IA, Jefferson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Lee County, IA, Linn County, IA, Louisa County, IA, Lucas County, IA, Mahaska County, IA, Marion County, IA, Marshall County, IA, Monroe County, IA, Muscatine County, IA, Poweshiek County, IA, Scott County, IA, Tama County, IA, Van Buren County, IA, Wapello County, IA, Washington County, IA, Winneshiek County, IA, Boone County, IL, Bureau County, IL, Carroll County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Henderson County, IL, Henry County, IL, Jo Daviess County, IL, Kane County, IL, Kendall County, IL, Knox County, IL, Lake County, IL, LaSalle County, IL, Lee County, IL, Marshall County, IL, McHenry County, IL, Mercer County, IL, Ogle County, IL, Putnam County, IL, Rock Island County, IL, Stark County, IL, Stephenson County, IL, Warren County, IL, Whiteside County, IL, Winnebago County, IL, Houston County, MN, Adams County, WI, Calumet 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, Jefferson County, WI, Juneau County, WI, Kenosha County, WI, La Crosse County, WI, Lafayette County, WI, Manitowoc County, WI, Marquette County, WI, Milwaukee County, WI, Monroe County, WI, Ozaukee County, WI, Racine County, WI, Richland County, WI, Rock County, WI, Sauk County, WI, Sheboygan County, WI, Vernon County, WI, Walworth County, WI, Washington County, WI, Waukesha County, WI, Waushara County, WI, Winnebago County, WI

The radar

The Quad Cities radar (KDVN), 73 km from the middle of the area, began a volume at 17:57 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

Davenport, (KDVN), launched 12:00Z, 6.0 hours before the alert went out and 70 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: 800 J/kg
Mixed-layer CIN: -238 J/kg
Mixed-layer LCL: 1634 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: 16 m²/s²
0-3 km storm-relative helicity: 55 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

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 2, 6:19 AM CDT	Mesoscale Discussion	SPC	Boone, Cook, DeKalb, DuPage, Kane, Kendall and 4 more	86 min
Aug 2, 5:22 PM CDT	Severe Thunderstorm Watch	SPC	Boone, Cook, DeKalb, DuPage, Ford, Grundy and 12 more	9 hr
Aug 1, 9:40 PM CDT	Mesoscale Discussion	SPC	Aitkin, Anoka, Becker, Benton, Big Stone, Carlton and 29 more	95 min
Aug 1, 10:35 PM CDT	Severe Thunderstorm Watch	SPC	Aitkin, Becker, Carlton, Cass, Clay, Crow Wing and 11 more	7 hr
Aug 2, 1:24 AM CDT	Mesoscale Discussion	SPC	Aitkin, Anoka, Benton, Carlton, Chisago, Crow Wing and 5 more	96 min
Aug 2, 3:32 AM CDT	Mesoscale Discussion	SPC	Aitkin, Anoka, Benton, Carlton, Chisago, Crow Wing and 5 more	88 min
Aug 2, 5:23 AM CDT	Severe Thunderstorm Watch	SPC	Anoka, Benton, Big Stone, Carver, Chippewa, Chisago and 25 more	7 hr
Aug 2, 9:02 AM CDT	Mesoscale Discussion	SPC	Chisago, Ramsey, Washington	58 min
Aug 2, 2:20 AM CDT	Severe Thunderstorm Watch	SPC	Ashland, Barron, Bayfield, Burnett, Chippewa, Clark and 24 more	10 hr
Aug 2, 11:51 AM CDT	Mesoscale Discussion	SPC	Ashland, Barron, Bayfield, Burnett, Chippewa, Douglas and 11 more	24 min

Nearby

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