Alert archive / Iowa / Mesoscale Discussions in 2017

Mesoscale Discussion 1528

August 18, 201735 counties in Iowa; Faribault County, Freeborn County, Martin County, Minnesota

The Storm Prediction Center issued this mesoscale discussion at Aug 18, 2017, 9:00 PM CDT for 35 counties in Iowa; Faribault County, Freeborn County, Martin County, Minnesota. It was in force for 60 min.

The area

The outline as issued.

The facts

Issued: Aug 18, 2017, 9:00 PM CDT (02:00 UTC)
Expired: Aug 18, 2017, 10:00 PM CDT
In force: 60 min
Issued by: the Storm Prediction Center

All 38 counties

Adair County, IA, Boone County, IA, Buena Vista County, IA, Calhoun County, IA, Carroll County, IA, Cerro Gordo County, IA, Clay County, IA, Dallas County, IA, Dickinson County, IA, Emmet County, IA, Franklin County, IA, Greene County, IA, Grundy County, IA, Guthrie County, IA, Hamilton County, IA, Hancock County, IA, Hardin County, IA, Humboldt County, IA, Jasper County, IA, Kossuth County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Marshall County, IA, O'Brien County, IA, Palo Alto County, IA, Pocahontas County, IA, Polk County, IA, Sac County, IA, Story County, IA, Warren County, IA, Webster County, IA, Winnebago County, IA, Worth County, IA, Wright County, IA, Faribault County, MN, Freeborn County, MN, Martin County, MN

The radar

The Des Moines radar (KDMX), 106 km from the middle of the area, began a volume at 02:02 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

Omaha, NE (KOAX), launched 00:00Z, 2.0 hours before the alert went out and 236 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: 1353 J/kg
Mixed-layer CIN: -118 J/kg
Mixed-layer LCL: 1673 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 30 m²/s²
0-3 km storm-relative helicity: 61 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.1

Open this sounding in Storm Lab

The text

As transmitted.

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Nearby

Mesoscale Discussions in Iowa, 2017 Mesoscale Discussions in Minnesota, 2017 Every mesoscale discussion in 2017

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.