Alert archive / Illinois / Mesoscale Discussions in 2004

Mesoscale Discussion 2044

August 18, 200424 counties in Illinois; 5 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Aug 18, 2004, 9:40 PM CDT for 24 counties in Illinois; 5 counties in Missouri. It was in force for 95 min.

The area

The outline as issued.

The facts

Issued: Aug 18, 2004, 9:40 PM CDT (02:40 UTC)
Expired: Aug 18, 2004, 11:15 PM CDT
In force: 95 min
Issued by: the Storm Prediction Center

All 29 counties

Adams County, IL, Brown County, IL, Cass County, IL, Champaign County, IL, Christian County, IL, DeWitt County, IL, Douglas County, IL, Fulton County, IL, Hancock County, IL, Logan County, IL, Macon County, IL, Mason County, IL, McDonough County, IL, McLean County, IL, Menard County, IL, Morgan County, IL, Moultrie County, IL, Peoria County, IL, Piatt County, IL, Sangamon County, IL, Schuyler County, IL, Shelby County, IL, Tazewell County, IL, Vermilion County, IL, Adair County, MO, Clark County, MO, Knox County, MO, Lewis County, MO, Scotland County, MO

The radar

The Lincoln radar (KILX), 128 km from the middle of the area, began a volume at 02:40 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

Davenport, (KDVN), launched 00:00Z, 2.7 hours before the alert went out and 168 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: 65 J/kg
Mixed-layer CIN: -102 J/kg
Mixed-layer LCL: 1117 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 227 m²/s²
0-3 km storm-relative helicity: 295 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.8

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
Aug 18, 7:26 PM CDT	Mesoscale Discussion	SPC	Adams, Brown, Cass, Champaign, Christian, Clark and 36 more	2 hr
Aug 19, 5:50 PM CDT	Mesoscale Discussion	SPC	Edwards, Franklin, Gallatin, Hamilton, Hardin, Jackson and 14 more	85 min

Nearby

Mesoscale Discussions in Illinois, 2004 Mesoscale Discussions in Missouri, 2004 Every mesoscale discussion in 2004

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.