Alert archive / Iowa / Mesoscale Discussions in 2011

Mesoscale Discussion 327

April 3, 20114 states

The Storm Prediction Center issued this mesoscale discussion at Apr 3, 2011, 4:49 PM CDT for 4 states. It was in force for 56 min.

The area

The outline as issued.

The facts

Issued: Apr 3, 2011, 4:49 PM CDT (21:49 UTC)
Expired: Apr 3, 2011, 5:45 PM CDT
In force: 56 min
Issued by: the Storm Prediction Center

All 52 counties

Appanoose County, IA, Benton County, IA, Black Hawk County, IA, Buchanan County, IA, Cedar County, IA, Clarke County, IA, Clinton County, IA, Davis County, IA, Decatur County, IA, Delaware County, IA, Des Moines County, IA, Dubuque County, IA, Henry County, IA, Iowa County, IA, Jackson County, IA, Jasper County, IA, Jefferson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Lee County, IA, Linn County, IA, Louisa County, IA, Lucas County, IA, Mahaska County, IA, Marion County, IA, Marshall County, IA, Monroe County, IA, Muscatine County, IA, Poweshiek County, IA, Scott County, IA, Tama County, IA, Van Buren County, IA, Wapello County, IA, Warren County, IA, Washington County, IA, Wayne County, IA, Carroll County, IL, Henderson County, IL, Henry County, IL, Jo Daviess County, IL, Mercer County, IL, Rock Island County, IL, Stephenson County, IL, Whiteside County, IL, Mercer County, MO, Putnam County, MO, Schuyler County, MO, Scotland County, MO, Grant County, WI, Green County, WI, Lafayette County, WI

The radar

The Quad Cities radar (KDVN), 107 km from the middle of the area, began a volume at 21:53 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.

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 9.8 hours before the alert went out and 114 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2141 m above ground
0-6 km bulk shear: 82 kt
0-1 km storm-relative helicity: 707 m²/s²
0-3 km storm-relative helicity: 803 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 3, 5:57 PM CDT	Tornado Watch	SPC	Bureau, Carroll, Hancock, Henderson, Henry, Jo Daviess and 10 more	6 hr
Apr 3, 5:59 PM CDT	Mesoscale Discussion	SPC	Buchanan, Clay, Clinton, Platte	61 min
Apr 3, 6:21 PM CDT	Severe Thunderstorm Watch	SPC	Adair, Andrew, Bates, Buchanan, Caldwell, Carroll and 28 more	6 hr

Nearby

Mesoscale Discussions in Iowa, 2011 Mesoscale Discussions in Illinois, 2011 Mesoscale Discussions in Missouri, 2011 Every mesoscale discussion in 2011

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.