Alert archive / Iowa / Mesoscale Discussions in 2016

Mesoscale Discussion 1479

August 4, 20164 states

The Storm Prediction Center issued this mesoscale discussion at Aug 4, 2016, 4:48 PM CDT for 4 states. It was in force for 87 min.

The area

The outline as issued.

The facts

Issued: Aug 4, 2016, 4:48 PM CDT (21:48 UTC)
Expired: Aug 4, 2016, 6:15 PM CDT
In force: 87 min
Issued by: the Storm Prediction Center

All 36 counties

Allamakee County, IA, Black Hawk County, IA, Bremer County, IA, Buchanan County, IA, Butler County, IA, Cerro Gordo County, IA, Chickasaw County, IA, Clayton County, IA, Delaware County, IA, Dubuque County, IA, Fayette County, IA, Floyd County, IA, Franklin County, IA, Grundy County, IA, Hardin County, IA, Howard County, IA, Marshall County, IA, Mitchell County, IA, Tama County, IA, Winneshiek County, IA, Wright County, IA, Jo Daviess County, IL, Fillmore County, MN, Houston County, MN, Columbia County, WI, Crawford County, WI, Dane County, WI, Grant County, WI, Green County, WI, Iowa County, WI, Jefferson County, WI, Lafayette County, WI, Marquette County, WI, Richland County, WI, Sauk County, WI, Vernon County, WI

The radar

The La Crosse radar (KARX), 75 km from the middle of the area, began a volume at 21:48 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

Davenport, (KDVN), launched 12:00Z, 9.8 hours before the alert went out and 179 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: 500 J/kg
Mixed-layer CIN: -126 J/kg
Mixed-layer LCL: 970 m above ground
0-6 km bulk shear: 16 kt
0-1 km storm-relative helicity: 10 m²/s²
0-3 km storm-relative helicity: 98 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 4, 12:15 PM CDT	Mesoscale Discussion	SPC	Jo Daviess	2 hr
Aug 4, 4:44 PM CDT	Severe Thunderstorm Watch	SPC	Carroll, Jo Daviess, Rock Island, Stephenson, Whiteside	6 hr
Aug 4, 3:58 AM CDT	Mesoscale Discussion	SPC	Dickinson, Osceola	62 min
Aug 4, 4:44 PM CDT	Mesoscale Discussion	SPC	Adair, Adams, Cass, Fremont, Mills, Montgomery and 2 more	3 hr
Aug 3, 9:07 PM CDT	Mesoscale Discussion	SPC	Aitkin, Becker, Beltrami, Cass, Clay, Clearwater and 15 more	113 min
Aug 3, 10:59 PM CDT	Severe Thunderstorm Watch	SPC	Becker, Beltrami, Big Stone, Cass, Clay, Clearwater and 21 more	7 hr
Aug 4, 2:59 AM CDT	Mesoscale Discussion	SPC	Aitkin, Benton, Carlton, Chisago, Crow Wing, Isanti and 5 more	31 min

Nearby

Mesoscale Discussions in Iowa, 2016 Mesoscale Discussions in Wisconsin, 2016 Mesoscale Discussions in Minnesota, 2016 Every mesoscale discussion in 2016

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.