Alert archive / Illinois / Mesoscale Discussions in 2011

Mesoscale Discussion 1486

July 3, 201131 counties in Illinois; Posey County, Indiana; 18 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Jul 3, 2011, 3:35 PM CDT for 31 counties in Illinois; Posey County, Indiana; 18 counties in Missouri. It was in force for 55 min.

The area

The outline as issued.

The facts

Issued: Jul 3, 2011, 3:35 PM CDT (20:35 UTC)
Expired: Jul 3, 2011, 4:30 PM CDT
In force: 55 min
Issued by: the Storm Prediction Center

All 50 counties

Bond County, IL, Calhoun County, IL, Clark County, IL, Clay County, IL, Clinton County, IL, Crawford County, IL, Cumberland County, IL, Edwards County, IL, Effingham County, IL, Fayette County, IL, Franklin County, IL, Greene County, IL, Hamilton County, IL, Jasper County, IL, Jefferson County, IL, Jersey County, IL, Lawrence County, IL, Macoupin County, IL, Madison County, IL, Marion County, IL, Monroe County, IL, Montgomery County, IL, Perry County, IL, Randolph County, IL, Richland County, IL, Saint Clair County, IL, Shelby County, IL, Wabash County, IL, Washington County, IL, Wayne County, IL, White County, IL, Posey County, IN, Audrain County, MO, Boone County, MO, Callaway County, MO, City of Saint Louis, MO, Cole County, MO, Crawford County, MO, Franklin County, MO, Gasconade County, MO, Jefferson County, MO, Lincoln County, MO, Maries County, MO, Montgomery County, MO, Osage County, MO, Pike County, MO, Saint Charles County, MO, Saint Louis County, MO, Warren County, MO, Washington County, MO

The radar

The St Louis radar (KLSX), 25 km from the middle of the area, began a volume at 20:38 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, 8.6 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: 1911 J/kg
Mixed-layer CIN: -40 J/kg
Mixed-layer LCL: 884 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: -10 m²/s²
0-3 km storm-relative helicity: 115 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.1

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
Jul 3, 12:26 PM CDT	Mesoscale Discussion	SPC	Bond, Calhoun, Clay, Clinton, Effingham, Fayette and 11 more	64 min
Jul 3, 1:15 PM CDT	Severe Thunderstorm Watch	SPC	Bond, Calhoun, Clay, Clinton, Crawford, Edwards and 22 more	6 hr
Jul 3, 5:19 PM CDT	Mesoscale Discussion	SPC	Bond, Calhoun, Clay, Clinton, Edwards, Fayette and 24 more	26 min
Jul 2, 8:50 PM CDT	Mesoscale Discussion	SPC	Carroll, Clinton, Howard, Tippecanoe, Tipton	55 min

Nearby

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