Alert archive / Illinois / Mesoscale Discussions in 2015

Mesoscale Discussion 264

April 9, 20154 states

The Storm Prediction Center issued this mesoscale discussion at Apr 9, 2015, 8:01 PM CDT for 4 states. It was in force for 89 min.

The area

The outline as issued.

The facts

Issued: Apr 9, 2015, 8:01 PM CDT (01:01 UTC)
Expired: Apr 9, 2015, 9:30 PM CDT
In force: 89 min
Issued by: the Storm Prediction Center

All 65 counties

Alexander County, IL, Bond County, IL, Clark County, IL, Clay County, IL, Clinton County, IL, Coles County, IL, Crawford County, IL, Cumberland County, IL, Douglas County, IL, Edgar County, IL, Edwards County, IL, Effingham County, IL, Fayette County, IL, Franklin County, IL, Gallatin County, IL, Hamilton County, IL, Hardin County, IL, Jackson County, IL, Jasper County, IL, Jefferson County, IL, Johnson County, IL, Lawrence County, IL, Madison County, IL, Marion County, IL, Massac County, IL, Monroe County, IL, Montgomery County, IL, Moultrie County, IL, Perry County, IL, Pope County, IL, Pulaski County, IL, Randolph County, IL, Richland County, IL, Saint Clair County, IL, Saline County, IL, Shelby County, IL, Union County, IL, Wabash County, IL, Washington County, IL, Wayne County, IL, White County, IL, Williamson County, IL, Clay County, IN, Gibson County, IN, Knox County, IN, Montgomery County, IN, Parke County, IN, Pike County, IN, Posey County, IN, Sullivan County, IN, Vanderburgh County, IN, Vermillion County, IN, Vigo County, IN, Ballard County, KY, Carlisle County, KY, McCracken County, KY, Union County, KY, Bollinger County, MO, Cape Girardeau County, MO, Madison County, MO, Mississippi County, MO, Perry County, MO, Saint Francois County, MO, Sainte Genevieve County, MO, Scott County, MO

The radar

The Evansville,IN radar (KVWX), 118 km from the middle of the area, began a volume at 01:02 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, 1.0 hours before the alert went out and 200 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: 1160 J/kg
Mixed-layer CIN: -28 J/kg
Mixed-layer LCL: 1435 m above ground
0-6 km bulk shear: 55 kt
0-1 km storm-relative helicity: 296 m²/s²
0-3 km storm-relative helicity: 356 m²/s²
Significant tornado parameter: 1.4
Supercell composite: 15.8

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
Apr 9, 7:09 PM CDT	Mesoscale Discussion	SPC	Boone, McHenry, Winnebago	96 min
Apr 9, 10:56 PM CDT	Mesoscale Discussion	SPC	Crawford, Edwards, Gallatin, Hamilton, Hardin, Johnson and 7 more	94 min
Apr 9, 8:27 PM CDT	Mesoscale Discussion	SPC	Elkhart, Fulton, Kosciusko, LaGrange, Marshall, Noble and 5 more	93 min
Apr 9, 8:55 PM CDT	Severe Thunderstorm Watch	SPC	Allen, Benton, Cass, DeKalb, Elkhart, Fulton and 20 more	5 hr
Apr 10, 12:37 AM CDT	Tornado Watch	SPC	Bartholomew, Clark, Crawford, Dearborn, Decatur, Dubois and 19 more	5 hr
Apr 10, 2:32 AM CDT	Mesoscale Discussion	SPC	Bath, Bell, Bourbon, Boyd, Breathitt, Carter and 44 more	58 min
Apr 10, 3:09 AM CDT	Severe Thunderstorm Watch	SPC	Bath, Bell, Boyd, Breathitt, Carter, Clay and 31 more	5 hr
Apr 10, 5:16 AM CDT	Mesoscale Discussion	SPC	Bell, Boyd, Breathitt, Carter, Clay, Elliott and 17 more	59 min
Apr 9, 10:01 PM CDT	Mesoscale Discussion	SPC	Dunklin, Pemiscot	119 min

Nearby

Mesoscale Discussions in Illinois, 2015 Mesoscale Discussions in Indiana, 2015 Mesoscale Discussions in Missouri, 2015 Every mesoscale discussion in 2015

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.