Alert archive / Iowa / Mesoscale Discussions in 2009

Mesoscale Discussion 591

April 26, 20094 states

The Storm Prediction Center issued this mesoscale discussion at Apr 26, 2009, 8:21 PM CDT for 4 states. It was in force for 54 min.

The area

The outline as issued.

The facts

Issued: Apr 26, 2009, 8:21 PM CDT (01:21 UTC)
Expired: Apr 26, 2009, 9:15 PM CDT
In force: 54 min
Issued by: the Storm Prediction Center

All 90 counties

Appanoose County, IA, Benton County, IA, Black Hawk County, IA, Bremer County, IA, Buchanan County, IA, Butler County, IA, Cedar County, IA, Chickasaw County, IA, Clarke County, IA, Clayton County, IA, Davis County, IA, Decatur County, IA, Delaware County, IA, Dubuque County, IA, Fayette County, IA, Grundy County, IA, Iowa County, IA, Jasper County, IA, Jefferson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Linn County, IA, Lucas County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Marshall County, IA, Monroe County, IA, Polk County, IA, Poweshiek County, IA, Ringgold County, IA, Tama County, IA, Taylor County, IA, Union County, IA, Wapello County, IA, Warren County, IA, Washington County, IA, Wayne County, IA, Anderson County, KS, Atchison County, KS, Brown County, KS, Chase County, KS, Coffey County, KS, Doniphan County, KS, Douglas County, KS, Franklin County, KS, Harvey County, KS, Jackson County, KS, Jefferson County, KS, Johnson County, KS, Leavenworth County, KS, Linn County, KS, Lyon County, KS, Marion County, KS, Miami County, KS, Morris County, KS, Osage County, KS, Shawnee County, KS, Wabaunsee County, KS, Wyandotte County, KS, Adair County, MO, Andrew County, MO, Buchanan County, MO, Caldwell County, MO, Carroll County, MO, Cass County, MO, Clay County, MO, Clinton County, MO, Daviess County, MO, DeKalb County, MO, Gentry County, MO, Grundy County, MO, Harrison County, MO, Holt County, MO, Jackson County, MO, Lafayette County, MO, Linn County, MO, Livingston County, MO, Mercer County, MO, Nodaway County, MO, Platte County, MO, Putnam County, MO, Ray County, MO, Schuyler County, MO, Sullivan County, MO, Worth County, MO, Grant County, WI, Iowa County, WI, Lafayette County, WI

The radar

The Pleasant Hill radar (KEAX), 159 km from the middle of the area, began a volume at 01:23 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

Topeka, KS (KTOP), launched 00:00Z, 1.4 hours before the alert went out and 167 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: 1568 J/kg
Mixed-layer CIN: -2 J/kg
Mixed-layer LCL: 841 m above ground
0-6 km bulk shear: 51 kt
0-1 km storm-relative helicity: 287 m²/s²
0-3 km storm-relative helicity: 332 m²/s²
Significant tornado parameter: 3.1
Supercell composite: 13.3

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, 11:15 PM CDT	Mesoscale Discussion	SPC	Davis, Iowa, Jefferson, Johnson, Keokuk, Linn and 3 more	60 min
Apr 26, 8:42 PM CDT	Mesoscale Discussion	SPC	Allen, Barber, Butler, Chase, Chautauqua, Comanche and 16 more	2 hr
Apr 27, 12:32 PM CDT	Mesoscale Discussion	SPC	Bourbon, Chautauqua, Cherokee, Crawford, Labette, Montgomery and 2 more	88 min
Apr 27, 12:47 PM CDT	Severe Thunderstorm Watch	SPC	Allen, Bourbon, Cherokee, Crawford, Labette, Montgomery and 2 more	6 hr
Apr 27, 3:28 PM CDT	Mesoscale Discussion	SPC	Cherokee, Labette	2 hr
Apr 27, 6:03 PM CDT	Mesoscale Discussion	SPC	Chautauqua, Cherokee, Crawford, Labette, Montgomery	27 min
Apr 27, 5:08 PM CDT	Mesoscale Discussion	SPC	Bollinger, Butler, Cape Girardeau, Dunklin, Mississippi, New Madrid and 3 more	97 min

Nearby

Mesoscale Discussions in Iowa, 2009 Mesoscale Discussions in Missouri, 2009 Mesoscale Discussions in Kansas, 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.