Alert archive / Iowa / Mesoscale Discussions in 2013

Mesoscale Discussion 863

May 29, 201338 counties in Iowa; 5 counties in Minnesota; 28 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at May 29, 2013, 5:54 PM CDT for 38 counties in Iowa; 5 counties in Minnesota; 28 counties in Wisconsin. It was in force for 66 min.

The area

The outline as issued.

The facts

Issued
May 29, 2013, 5:54 PM CDT (22:54 UTC)
Expired
May 29, 2013, 7:00 PM CDT
In force
66 min
Issued by
the Storm Prediction Center
All 71 counties

Allamakee County, IA, Appanoose County, IA, Benton County, IA, Black Hawk County, IA, Bremer County, IA, Buchanan County, IA, Butler County, IA, Chickasaw County, IA, Clarke County, IA, Clayton County, IA, Dallas County, IA, Davis County, IA, Decatur County, IA, Delaware County, IA, Fayette County, IA, Grundy County, IA, Hardin County, IA, Howard County, IA, Iowa County, IA, Jasper County, IA, Johnson 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, Story County, IA, Tama County, IA, Union County, IA, Wapello County, IA, Warren County, IA, Wayne County, IA, Winneshiek County, IA, Fillmore County, MN, Houston County, MN, Olmsted County, MN, Wabasha County, MN, Winona County, MN, Adams County, WI, Barron County, WI, Buffalo County, WI, Chippewa County, WI, Clark County, WI, Crawford County, WI, Dunn County, WI, Eau Claire County, WI, Grant County, WI, Jackson County, WI, Juneau County, WI, La Crosse County, WI, Lincoln County, WI, Marathon County, WI, Monroe County, WI, Pepin County, WI, Pierce County, WI, Polk County, WI, Portage County, WI, Richland County, WI, Rusk County, WI, Saint Croix County, WI, Sauk County, WI, Taylor County, WI, Trempealeau County, WI, Vernon County, WI, Waushara County, WI, Wood County, WI

The radar

The La Crosse radar (KARX), 92 km from the middle of the area, began a volume at 22:55 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, 10.9 hours before the alert went out and 199 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-pSkew-T log-p diagram, Davenport, at 12:00Z on 2013-05-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Davenport, at 12:00Z on 2013-05-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -64 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
3 J/kg
Mixed-layer CIN
-179 J/kg
Mixed-layer LCL
1192 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
-64 m²/s²
0-3 km storm-relative helicity
90 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.

IssuedProductOfficeCountiesLasted
May 28, 9:20 PM CDTMesoscale DiscussionSPCAdams, Appanoose, Clarke, Davis, Decatur, Fremont and 10 more55 min
May 29, 8:54 AM CDTMesoscale DiscussionSPCAdair, Adams, Audubon, Boone, Buena Vista, Calhoun and 33 more2 hr
May 29, 2:39 PM CDTMesoscale DiscussionSPCAllamakee, Benton, Black Hawk, Bremer, Buchanan, Chickasaw and 19 more66 min
May 29, 2:56 PM CDTSevere Thunderstorm WatchSPCAllamakee, Appanoose, Benton, Black Hawk, Bremer, Buchanan and 29 more7 hr
May 29, 3:33 PM CDTTornado WatchSPCFremont, Mills7 hr
May 29, 6:24 PM CDTTornado WatchSPCAdams, Audubon, Buena Vista, Carroll, Cass, Cherokee and 20 more4 hr
May 29, 6:49 PM CDTSevere Thunderstorm WatchSPCColumbia, Dane, Dodge, Fond du Lac, Green, Green Lake and 17 more3 hr

Nearby

Mesoscale Discussions in Iowa, 2013Mesoscale Discussions in Wisconsin, 2013Mesoscale Discussions in Minnesota, 2013Every mesoscale discussion in 2013

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.