Alert archive / Illinois / Mesoscale Discussions in 2009

Mesoscale Discussion 993

June 8, 20094 states

The Storm Prediction Center issued this mesoscale discussion at Jun 8, 2009, 3:53 PM CDT for 4 states. It was in force for 67 min.

The area

The outline as issued.

The facts

Issued: Jun 8, 2009, 3:53 PM CDT (20:53 UTC)
Expired: Jun 8, 2009, 5:00 PM CDT
In force: 67 min
Issued by: the Storm Prediction Center

All 27 counties

Boone County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Grundy County, IL, Iroquois County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, Lake County, IL, LaSalle County, IL, Livingston County, IL, Marshall County, IL, McHenry County, IL, Putnam County, IL, Will County, IL, Woodford County, IL, Jasper County, IN, Lake County, IN, LaPorte County, IN, Newton County, IN, Porter County, IN, Berrien County, MI, Kenosha County, WI, Milwaukee County, WI, Racine County, WI, Walworth County, WI

The radar

The Chicago radar (KLOT), 38 km from the middle of the area, began a volume at 20:55 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, 8.9 hours before the alert went out and 204 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: 972 J/kg
Mixed-layer CIN: -140 J/kg
Mixed-layer LCL: 693 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: 78 m²/s²
0-3 km storm-relative helicity: 106 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 5.2

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
Jun 7, 11:09 PM CDT	Severe Thunderstorm Watch	SPC	Adams, Brown, Hancock, Henderson, McDonough, Mercer and 1 more	6 hr
Jun 8, 3:25 AM CDT	Mesoscale Discussion	SPC	Adams, Brown, Hancock, Henderson, McDonough, Mercer and 2 more	65 min
Jun 8, 8:49 AM CDT	Mesoscale Discussion	SPC	Bond, Clark, Clay, Clinton, Coles, Crawford and 26 more	86 min
Jun 8, 11:54 AM CDT	Mesoscale Discussion	SPC	Bond, Boone, Brown, Bureau, Calhoun, Cass and 43 more	96 min
Jun 8, 1:23 PM CDT	Severe Thunderstorm Watch	SPC	Boone, Bureau, Cook, DeKalb, DuPage, Grundy and 10 more	6 hr
Jun 8, 3:20 PM CDT	Mesoscale Discussion	SPC	Bond, Clinton, Franklin, Jackson, Jefferson, Jersey and 9 more	85 min
Jun 8, 4:33 PM CDT	Severe Thunderstorm Watch	SPC	Alexander, Bond, Champaign, Christian, Clark, Clay and 37 more	5 hr
Jun 8, 5:46 PM CDT	Mesoscale Discussion	SPC	Lake	59 min
Jun 8, 2:34 PM CDT	Mesoscale Discussion	SPC	Elkhart, Kosciusko, LaGrange, Marshall, Noble, Steuben	56 min
Jun 8, 3:02 PM CDT	Tornado Watch	SPC	Allegan, Barry, Bay, Calhoun, Clinton, Eaton and 27 more	6 hr

Nearby

Mesoscale Discussions in Illinois, 2009 Mesoscale Discussions in Indiana, 2009 Mesoscale Discussions in Wisconsin, 2009 Every mesoscale discussion in 2009

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.