Alert archive / Iowa / Mesoscale Discussions in 2018

Mesoscale Discussion 1383

August 28, 20186 counties in Iowa

The Storm Prediction Center issued this mesoscale discussion at Aug 28, 2018, 6:07 PM CDT for 6 counties in Iowa. It was in force for 53 min.

The area

The outline as issued.

The facts

Issued: Aug 28, 2018, 6:07 PM CDT (23:07 UTC)
Expired: Aug 28, 2018, 7:00 PM CDT
In force: 53 min
Issued by: the Storm Prediction Center

Counties Cedar County, IA, Iowa County, IA, Johnson County, IA, Keokuk County, IA, Muscatine County, IA, Washington County, IA

The radar

The Quad Cities radar (KDVN), 79 km from the middle of the area, began a volume at 23:12 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, 11.1 hours before the alert went out and 86 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: 955 J/kg
Mixed-layer CIN: -230 J/kg
Mixed-layer LCL: 1046 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 360 m²/s²
0-3 km storm-relative helicity: 487 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.8

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 28, 3:12 AM CDT	Mesoscale Discussion	SPC	Cherokee, Clay, Dickinson, Emmet, Lyon, O'Brien and 3 more	3 hr
Aug 28, 7:50 AM CDT	Mesoscale Discussion	SPC	Allamakee, Black Hawk, Bremer, Butler, Cerro Gordo, Chickasaw and 15 more	115 min
Aug 28, 12:14 PM CDT	Mesoscale Discussion	SPC	Allamakee, Benton, Black Hawk, Boone, Bremer, Buchanan and 21 more	2 hr
Aug 28, 1:14 PM CDT	Severe Thunderstorm Watch	SPC	Allamakee, Black Hawk, Bremer, Buchanan, Butler, Cerro Gordo and 18 more	8 hr
Aug 28, 4:45 PM CDT	Mesoscale Discussion	SPC	Appanoose, Cedar, Clarke, Davis, Decatur, Des Moines and 21 more	60 min
Aug 28, 5:06 PM CDT	Severe Thunderstorm Watch	SPC	Appanoose, Benton, Cedar, Clinton, Davis, Des Moines and 20 more	6 hr

Nearby

Mesoscale Discussions in Iowa, 2018 Every mesoscale discussion in 2018

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.