Alert archive / Illinois / Mesoscale Discussions in 2008

Mesoscale Discussion 684

April 22, 200816 counties in Illinois; Cape Girardeau County, Perry County, Scott County, Missouri

The Storm Prediction Center issued this mesoscale discussion at Apr 22, 2008, 9:41 AM CDT for 16 counties in Illinois; Cape Girardeau County, Perry County, Scott County, Missouri. It was in force for 94 min.

The area

The outline as issued.

The facts

Issued: Apr 22, 2008, 9:41 AM CDT (14:41 UTC)
Expired: Apr 22, 2008, 11:15 AM CDT
In force: 94 min
Issued by: the Storm Prediction Center

Counties Alexander County, IL, Bond County, IL, Clay County, IL, Clinton County, IL, Effingham County, IL, Fayette County, IL, Franklin County, IL, Jackson County, IL, Jefferson County, IL, Marion County, IL, Perry County, IL, Pulaski County, IL, Union County, IL, Washington County, IL, Wayne County, IL, Williamson County, IL, Cape Girardeau County, MO, Perry County, MO, Scott County, MO

The radar

The St Louis radar (KLSX), 129 km from the middle of the area, began a volume at 14:44 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, 2.7 hours before the alert went out and 222 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: 13 J/kg
Mixed-layer CIN: -475 J/kg
Mixed-layer LCL: 1323 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: 85 m²/s²
0-3 km storm-relative helicity: 72 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
Apr 21, 7:03 PM CDT	Severe Thunderstorm Watch	SPC	Andrew, Buchanan, Clinton, DeKalb, Holt, Platte	7 hr
Apr 21, 10:38 PM CDT	Mesoscale Discussion	SPC	Andrew, Buchanan, Clinton, DeKalb, Holt, Platte	2 hr
Apr 22, 1:14 AM CDT	Mesoscale Discussion	SPC	Barton, Bates, Caldwell, Cass, Cedar, Clay and 10 more	91 min
Apr 22, 7:42 AM CDT	Mesoscale Discussion	SPC	Barry, Carter, Christian, Douglas, Greene, Howell and 10 more	63 min
Apr 22, 7:49 AM CDT	Severe Thunderstorm Watch	SPC	Barry, Christian, Dent, Douglas, Greene, Howell and 11 more	6 hr
Apr 22, 10:12 AM CDT	Mesoscale Discussion	SPC	Barry, Christian, Douglas, Howell, McDonald, Oregon and 3 more	93 min
Apr 22, 10:47 AM CDT	Severe Thunderstorm Watch	SPC	Dunklin, Pemiscot	5 hr
Apr 22, 12:16 PM CDT	Mesoscale Discussion	SPC	Dunklin, Ozark, Pemiscot, Taney	89 min
Apr 22, 2:06 PM CDT	Severe Thunderstorm Watch	SPC	Barry, Christian, Lawrence, McDonald, Newton, Stone and 1 more	7 hr
Apr 22, 3:30 PM CDT	Mesoscale Discussion	SPC	Barry, Christian, Greene, Lawrence, McDonald, Newton and 2 more	90 min
Apr 22, 6:51 PM CDT	Mesoscale Discussion	SPC	Barry, Christian, Greene, McDonald, Newton, Stone	114 min

Nearby

Mesoscale Discussions in Illinois, 2008 Mesoscale Discussions in Missouri, 2008 Every mesoscale discussion in 2008

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.