Alert archive / Illinois / Mesoscale Discussions in 2011

Mesoscale Discussion 2111

September 3, 20114 states

The Storm Prediction Center issued this mesoscale discussion at Sep 3, 2011, 5:02 PM CDT for 4 states. It was in force for 58 min.

The area

The outline as issued.

The facts

Issued: Sep 3, 2011, 5:02 PM CDT (22:02 UTC)
Expired: Sep 3, 2011, 6:00 PM CDT
In force: 58 min
Issued by: the Storm Prediction Center

All 73 counties

Bureau County, IL, Cook County, IL, DuPage County, IL, Ford County, IL, Fulton County, IL, Grundy County, IL, Hancock County, IL, Henderson County, IL, Henry County, IL, Iroquois County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, Knox County, IL, LaSalle County, IL, Livingston County, IL, Marshall County, IL, Mason County, IL, McDonough County, IL, McLean County, IL, Mercer County, IL, Peoria County, IL, Putnam County, IL, Schuyler County, IL, Stark County, IL, Tazewell County, IL, Warren County, IL, Will County, IL, Woodford County, IL, Benton County, IN, Cass County, IN, DeKalb County, IN, Elkhart County, IN, Fulton County, IN, Jasper County, IN, Kosciusko County, IN, LaGrange County, IN, Lake County, IN, LaPorte County, IN, Marshall County, IN, Newton County, IN, Noble County, IN, Porter County, IN, Pulaski County, IN, Saint Joseph County, IN, Starke County, IN, Steuben County, IN, White County, IN, Berrien County, MI, Branch County, MI, Calhoun County, MI, Cass County, MI, Eaton County, MI, Genesee County, MI, Hillsdale County, MI, Ingham County, MI, Jackson County, MI, Kalamazoo County, MI, Lapeer County, MI, Lenawee County, MI, Livingston County, MI, Macomb County, MI, Monroe County, MI, Oakland County, MI, Saint Clair County, MI, Saint Joseph County, MI, Sanilac County, MI, Shiawassee County, MI, Washtenaw County, MI, Wayne County, MI, Fulton County, OH, Lucas County, OH, Williams County, OH

The radar

The Northern Indiana radar (KIWX), 82 km from the middle of the area, began a volume at 22:04 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

Lincoln, IL (KILX), launched 12:00Z, 10.0 hours before the alert went out and 227 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: 1443 J/kg
Mixed-layer CIN: -94 J/kg
Mixed-layer LCL: 1535 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: -21 m²/s²
0-3 km storm-relative helicity: 11 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
Sep 2, 11:56 PM CDT	Mesoscale Discussion	SPC	Carroll, Jo Daviess, Ogle, Stephenson, Whiteside, Winnebago	94 min
Sep 3, 12:48 AM CDT	Severe Thunderstorm Watch	SPC	Boone, Jo Daviess, McHenry, Stephenson, Winnebago	6 hr
Sep 3, 12:24 PM CDT	Mesoscale Discussion	SPC	Bureau, Cook, DeKalb, DuPage, Ford, Grundy and 13 more	66 min
Sep 3, 3:05 PM CDT	Severe Thunderstorm Watch	SPC	Bureau, Cook, DuPage, Ford, Fulton, Grundy and 23 more	7 hr
Sep 3, 5:53 AM CDT	Mesoscale Discussion	SPC	Clinton, Genesee, Gratiot, Ionia, Isabella, Kent and 5 more	97 min
Sep 3, 6:22 AM CDT	Severe Thunderstorm Watch	SPC	Allegan, Barry, Bay, Clinton, Eaton, Genesee and 19 more	5 hr
Sep 3, 9:45 AM CDT	Mesoscale Discussion	SPC	Arenac, Bay, Huron, Sanilac, Tuscola	60 min

Nearby

Mesoscale Discussions in Illinois, 2011 Mesoscale Discussions in Michigan, 2011 Mesoscale Discussions in Indiana, 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.