Alert archive / Illinois / Mesoscale Discussions in 2009

Mesoscale Discussion 822

May 13, 200929 counties in Illinois; 29 counties in Indiana; 15 counties in Michigan

The Storm Prediction Center issued this mesoscale discussion at May 13, 2009, 10:17 PM CDT for 29 counties in Illinois; 29 counties in Indiana; 15 counties in Michigan. It was in force for 58 min.

The area

The outline as issued.

The facts

Issued: May 13, 2009, 10:17 PM CDT (03:17 UTC)
Expired: May 13, 2009, 11:15 PM CDT
In force: 58 min
Issued by: the Storm Prediction Center

All 73 counties

Champaign County, IL, Cook County, IL, DeKalb County, IL, DeWitt County, IL, Douglas County, IL, DuPage County, IL, Edgar County, IL, Ford 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, Logan County, IL, Macon County, IL, Marshall County, IL, McLean County, IL, Moultrie County, IL, Peoria County, IL, Piatt County, IL, Putnam County, IL, Sangamon County, IL, Tazewell County, IL, Vermilion County, IL, Will County, IL, Woodford County, IL, Benton County, IN, Boone County, IN, Carroll County, IN, Cass County, IN, Clinton County, IN, Elkhart County, IN, Fountain County, IN, Fulton County, IN, Howard County, IN, Jasper County, IN, Kosciusko County, IN, LaGrange County, IN, Lake County, IN, LaPorte County, IN, Marshall County, IN, Miami County, IN, Montgomery County, IN, Newton County, IN, Noble County, IN, Parke County, IN, Porter County, IN, Pulaski County, IN, Putnam County, IN, Saint Joseph County, IN, Starke County, IN, Tippecanoe County, IN, Vermillion County, IN, Warren County, IN, White County, IN, Allegan County, MI, Barry County, MI, Berrien County, MI, Branch County, MI, Calhoun County, MI, Cass County, MI, Ionia County, MI, Kalamazoo County, MI, Kent County, MI, Mecosta County, MI, Montcalm County, MI, Newaygo County, MI, Ottawa County, MI, Saint Joseph County, MI, Van Buren County, MI

The radar

The Chicago radar (KLOT), 50 km from the middle of the area, began a volume at 03:18 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

Lincoln, IL (KILX), launched 00:00Z, 3.3 hours before the alert went out and 193 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: 1574 J/kg
Mixed-layer CIN: -113 J/kg
Mixed-layer LCL: 930 m above ground
0-6 km bulk shear: 46 kt
0-1 km storm-relative helicity: 350 m²/s²
0-3 km storm-relative helicity: 407 m²/s²
Significant tornado parameter: 2.0
Supercell composite: 8.7

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
May 13, 7:05 PM CDT	Mesoscale Discussion	SPC	Adams, Brown, Cass, Fulton, Greene, Hancock and 15 more	85 min
May 13, 8:35 PM CDT	Mesoscale Discussion	SPC	Adams, Boone, Brown, Bureau, Carroll, Cass and 47 more	85 min
May 13, 9:56 PM CDT	Severe Thunderstorm Watch	SPC	Bond, Calhoun, Cass, Christian, Clark, Clay and 27 more	6 hr
May 13, 10:51 PM CDT	Severe Thunderstorm Watch	SPC	Champaign, Cook, DeWitt, DuPage, Ford, Grundy and 12 more	4 hr
May 13, 11:27 PM CDT	Mesoscale Discussion	SPC	Alexander, Bond, Calhoun, Clark, Clay, Clinton and 36 more	93 min
May 14, 1:01 AM CDT	Severe Thunderstorm Watch	SPC	Alexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 13 more	5 hr
May 14, 12:42 AM CDT	Severe Thunderstorm Watch	SPC	Adams, Allen, Bartholomew, Blackford, Boone, Brown and 49 more	4 hr
May 14, 4:37 AM CDT	Mesoscale Discussion	SPC	Dearborn, Ohio, Switzerland	53 min

Nearby

Mesoscale Discussions in Illinois, 2009 Mesoscale Discussions in Indiana, 2009 Mesoscale Discussions in Michigan, 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.