Alert archive / Illinois / Mesoscale Discussions in 2003

Mesoscale Discussion 2329

August 31, 200319 counties in Illinois; 9 counties in Indiana

The Storm Prediction Center issued this mesoscale discussion at Aug 31, 2003, 5:11 PM CDT for 19 counties in Illinois; 9 counties in Indiana. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Aug 31, 2003, 5:11 PM CDT (22:11 UTC)
Expired: Aug 31, 2003, 7:15 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 28 counties

Bond County, IL, Clark County, IL, Clay County, IL, Clinton County, IL, Coles County, IL, Crawford County, IL, Cumberland County, IL, Effingham County, IL, Fayette County, IL, Jasper County, IL, Jefferson County, IL, Lawrence County, IL, Madison County, IL, Marion County, IL, Montgomery County, IL, Richland County, IL, Shelby County, IL, Washington County, IL, Wayne County, IL, Brown County, IN, Clay County, IN, Daviess County, IN, Greene County, IN, Knox County, IN, Monroe County, IN, Owen County, IN, Sullivan County, IN, Vigo County, IN

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Tornado Watch 913Aug 31, 5:25 PM CDT

The nearest sounding before it

Nashville Metro, TN (KBNA), launched 12:00Z, 10.2 hours before the alert went out and 328 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: 1395 J/kg
Mixed-layer CIN: -14 J/kg
Mixed-layer LCL: 555 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: 64 m²/s²
0-3 km storm-relative helicity: 70 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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
Aug 31, 5:25 PM CDT	Tornado Watch	SPC	Bond, Christian, Clark, Clay, Clinton, Coles and 19 more	6 hr

Nearby

Mesoscale Discussions in Illinois, 2003 Mesoscale Discussions in Indiana, 2003 Every mesoscale discussion in 2003

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.