Alert archive / Missouri / Mesoscale Discussions in 2004

Mesoscale Discussion 2120

August 26, 2004Calhoun County, Monroe County, Illinois; 18 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Aug 26, 2004, 3:50 PM CDT for Calhoun County, Monroe County, Illinois; 18 counties in Missouri. It was in force for 115 min.

The area

The outline as issued.

The facts

Issued: Aug 26, 2004, 3:50 PM CDT (20:50 UTC)
Expired: Aug 26, 2004, 5:45 PM CDT
In force: 115 min
Issued by: the Storm Prediction Center

Counties Calhoun County, IL, Monroe County, IL, City of Saint Louis, MO, Crawford County, MO, Franklin County, MO, Gasconade County, MO, Iron County, MO, Jefferson County, MO, Lincoln County, MO, Madison County, MO, Montgomery County, MO, Perry County, MO, Pike County, MO, Reynolds 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), 60 km from the middle of the area, began a volume at 20:50 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, 8.8 hours before the alert went out and 279 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: 467 J/kg
Mixed-layer CIN: -107 J/kg
Mixed-layer LCL: 756 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 300 m²/s²
0-3 km storm-relative helicity: 317 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 12.8

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 25, 7:47 PM CDT	Mesoscale Discussion	SPC	Alexander, Bond, Calhoun, Cass, Champaign, Christian and 48 more	58 min
Aug 25, 9:57 PM CDT	Mesoscale Discussion	SPC	Adams, Hancock	93 min
Aug 25, 9:35 PM CDT	Mesoscale Discussion	SPC	Bates, Cass, Jackson	55 min
Aug 26, 4:10 PM CDT	Tornado Watch	SPC	Atchison, Gentry, Harrison, Holt, Mercer, Nodaway and 1 more	6 hr

Nearby

Mesoscale Discussions in Missouri, 2004 Mesoscale Discussions in Illinois, 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.