Alert archive / Illinois / Mesoscale Discussions in 2011

Mesoscale Discussion 160

February 27, 201115 counties in Illinois; 14 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Feb 27, 2011, 10:41 PM CST for 15 counties in Illinois; 14 counties in Missouri. It was in force for 94 min.

The area

The outline as issued.

The facts

Issued: Feb 27, 2011, 10:41 PM CST (04:41 UTC)
Expired: Feb 28, 2011, 12:15 AM CST
In force: 94 min
Issued by: the Storm Prediction Center

All 29 counties

Bond County, IL, Clinton County, IL, Franklin County, IL, Jackson County, IL, Jefferson County, IL, Jersey County, IL, Madison County, IL, Marion County, IL, Monroe County, IL, Perry County, IL, Randolph County, IL, Saint Clair County, IL, Union County, IL, Washington County, IL, Williamson County, IL, Bollinger County, MO, Cape Girardeau County, MO, City of Saint Louis, MO, Franklin County, MO, Iron County, MO, Jefferson County, MO, Madison County, MO, Perry County, MO, Saint Charles County, MO, Saint Francois County, MO, Saint Louis County, MO, Sainte Genevieve County, MO, Warren County, MO, Washington County, MO

The radar

The St Louis radar (KLSX), 66 km from the middle of the area, began a volume at 04:44 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 00:00Z, 4.7 hours before the alert went out and 243 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: 124 J/kg
Mixed-layer CIN: -220 J/kg
Mixed-layer LCL: 494 m above ground
0-6 km bulk shear: 76 kt
0-1 km storm-relative helicity: 89 m²/s²
0-3 km storm-relative helicity: 210 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.5

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
Feb 27, 8:25 PM CST	Mesoscale Discussion	SPC	Alexander, Bond, Christian, Clark, Clay, Clinton and 39 more	65 min
Feb 27, 8:49 PM CST	Mesoscale Discussion	SPC	Boone, Bureau, Carroll, Cook, DeKalb, DuPage and 10 more	6 hr
Feb 27, 9:40 PM CST	Tornado Watch	SPC	Alexander, Bond, Calhoun, Clinton, Edwards, Fayette and 27 more	6 hr
Feb 27, 11:46 PM CST	Tornado Watch	SPC	Clark, Clay, Crawford, Cumberland, Effingham, Jasper and 2 more	5 hr
Feb 28, 1:05 AM CST	Mesoscale Discussion	SPC	Alexander, Gallatin, Hardin, Massac, Pope, Pulaski	25 min
Feb 27, 7:03 PM CST	Mesoscale Discussion	SPC	Barton, Camden, Cedar, Christian, Dade, Dallas and 17 more	87 min
Feb 27, 7:24 PM CST	Tornado Watch	SPC	Barry, Barton, Benton, Camden, Cedar, Christian and 28 more	7 hr
Feb 28, 1:33 AM CST	Tornado Watch	SPC	Dunklin, Mississippi, New Madrid, Pemiscot	7 hr

Nearby

Mesoscale Discussions in Illinois, 2011 Mesoscale Discussions in Missouri, 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.