Alert archive / Illinois / Mesoscale Discussions in 2007

Mesoscale Discussion 1878

August 23, 200717 counties in Illinois; 4 counties in Iowa

The Storm Prediction Center issued this mesoscale discussion at Aug 23, 2007, 11:07 PM CDT for 17 counties in Illinois; 4 counties in Iowa. It was in force for 53 min.

The area

The outline as issued.

The facts

Issued: Aug 23, 2007, 11:07 PM CDT (04:07 UTC)
Expired: Aug 24, 2007, 12:00 AM CDT
In force: 53 min
Issued by: the Storm Prediction Center

All 21 counties

Des Moines County, IA, Henry County, IA, Louisa County, IA, Washington County, IA, Bureau County, IL, Grundy County, IL, Henderson County, IL, Henry County, IL, Kankakee County, IL, Kendall County, IL, Knox County, IL, LaSalle County, IL, Livingston County, IL, Marshall County, IL, Mercer County, IL, Peoria County, IL, Putnam County, IL, Stark County, IL, Warren County, IL, Will County, IL, Woodford County, IL

The radar

The Quad Cities radar (KDVN), 99 km from the middle of the area, began a volume at 04:06 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, 4.1 hours before the alert went out and 94 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: 443 J/kg
Mixed-layer CIN: -149 J/kg
Mixed-layer LCL: 1230 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: 160 m²/s²
0-3 km storm-relative helicity: 193 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 3.0

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 23, 7:10 PM CDT	Severe Thunderstorm Watch	SPC	Bureau, Cook, Ford, Fulton, Grundy, Hancock and 20 more	5 hr
Aug 24, 11:12 AM CDT	Mesoscale Discussion	SPC	Bond, Calhoun, Christian, Clay, Clinton, Coles and 24 more	93 min
Aug 24, 12:19 PM CDT	Severe Thunderstorm Watch	SPC	Bond, Calhoun, Cass, Champaign, Christian, Clark and 37 more	8 hr
Aug 24, 2:44 PM CDT	Mesoscale Discussion	SPC	Bond, Champaign, Christian, Clark, Clay, Clinton and 34 more	91 min
Aug 24, 3:04 PM CDT	Severe Thunderstorm Watch	SPC	Ford, Iroquois	7 hr
Aug 24, 5:50 PM CDT	Mesoscale Discussion	SPC	Bond, Champaign, Christian, Clark, Clay, Clinton and 39 more	85 min
Aug 23, 7:47 PM CDT	Mesoscale Discussion	SPC	Adair, Adams, Appanoose, Cass, Clarke, Davis and 17 more	118 min
Aug 23, 7:55 PM CDT	Mesoscale Discussion	SPC	Adair, Adams, Appanoose, Cass, Clarke, Davis and 17 more	2 hr
Aug 23, 11:01 PM CDT	Mesoscale Discussion	SPC	Adair, Adams, Appanoose, Clarke, Davis, Decatur and 17 more	119 min

Nearby

Mesoscale Discussions in Illinois, 2007 Mesoscale Discussions in Iowa, 2007 Every mesoscale discussion in 2007

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.