Alert archive / Missouri / Mesoscale Discussions in 2009

Mesoscale Discussion 571

April 25, 20096 counties in Illinois; 5 counties in Iowa; 18 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Apr 25, 2009, 9:23 PM CDT for 6 counties in Illinois; 5 counties in Iowa; 18 counties in Missouri. It was in force for 67 min.

The area

The outline as issued.

The facts

Issued: Apr 25, 2009, 9:23 PM CDT (02:23 UTC)
Expired: Apr 25, 2009, 10:30 PM CDT
In force: 67 min
Issued by: the Storm Prediction Center

All 29 counties

Davis County, IA, Des Moines County, IA, Henry County, IA, Lee County, IA, Van Buren County, IA, Hancock County, IL, Henderson County, IL, Knox County, IL, McDonough County, IL, Mercer County, IL, Warren County, IL, Adair County, MO, Buchanan County, MO, Caldwell County, MO, Clark County, MO, Clay County, MO, Clinton County, MO, Daviess County, MO, DeKalb County, MO, Grundy County, MO, Knox County, MO, Lewis County, MO, Linn County, MO, Livingston County, MO, Macon County, MO, Putnam County, MO, Schuyler County, MO, Scotland County, MO, Sullivan County, MO

The radar

The Des Moines radar (KDMX), 192 km from the middle of the area, began a volume at 02:24 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 watches that followed

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

Severe Thunderstorm Watch 185Apr 25, 10:10 PM CDT

The nearest sounding before it

Topeka, KS (KTOP), launched 00:00Z, 2.4 hours before the alert went out and 303 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: 421 J/kg
Mixed-layer CIN: -157 J/kg
Mixed-layer LCL: 554 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: 298 m²/s²
0-3 km storm-relative helicity: 389 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 10.6

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 26, 2:00 PM CDT	Mesoscale Discussion	SPC	Boone, Carroll, DeKalb, Jo Daviess, Kane, Lee and 4 more	60 min
Apr 26, 5:02 PM CDT	Tornado Watch	SPC	Jo Daviess, Stephenson	6 hr
Apr 26, 5:14 PM CDT	Mesoscale Discussion	SPC	Jo Daviess, Stephenson	61 min
Apr 25, 7:17 PM CDT	Mesoscale Discussion	SPC	Appanoose, Davis, Wapello, Wayne	58 min
Apr 25, 10:09 PM CDT	Severe Thunderstorm Watch	SPC	Fremont, Page	6 hr
Apr 26, 9:18 AM CDT	Mesoscale Discussion	SPC	Audubon, Crawford, Harrison, Mills, Monona, Pottawattamie and 2 more	27 min
Apr 26, 9:34 AM CDT	Severe Thunderstorm Watch	SPC	Audubon, Buena Vista, Calhoun, Carroll, Cass, Cherokee and 29 more	6 hr
Apr 26, 12:30 PM CDT	Mesoscale Discussion	SPC	Adair, Adams, Audubon, Boone, Cass, Dallas and 13 more	60 min
Apr 26, 12:48 PM CDT	Tornado Watch	SPC	Adair, Adams, Audubon, Boone, Butler, Calhoun and 33 more	4 hr
Apr 26, 2:41 PM CDT	Mesoscale Discussion	SPC	Adair, Adams, Audubon, Boone, Buena Vista, Calhoun and 35 more	3 hr
Apr 26, 6:14 PM CDT	Mesoscale Discussion	SPC	Adams, Appanoose, Benton, Black Hawk, Bremer, Buchanan and 40 more	61 min
Apr 26, 2:10 AM CDT	Mesoscale Discussion	SPC	Andrew, Atchison, Bates, Buchanan, Caldwell, Carroll and 23 more	95 min

Nearby

Mesoscale Discussions in Missouri, 2009 Mesoscale Discussions in Illinois, 2009 Mesoscale Discussions in Iowa, 2009 Every mesoscale discussion in 2009

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.