Alert archive / Iowa / Mesoscale Discussions in 2014

Mesoscale Discussion 1735

September 19, 201414 counties in Iowa

The Storm Prediction Center issued this mesoscale discussion at Sep 19, 2014, 11:45 PM CDT for 14 counties in Iowa. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Sep 19, 2014, 11:45 PM CDT (04:45 UTC)
Expired: Sep 20, 2014, 1:45 AM CDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 20%

Counties Butler County, IA, Calhoun County, IA, Cerro Gordo County, IA, Floyd County, IA, Franklin County, IA, Hamilton County, IA, Hancock County, IA, Hardin County, IA, Humboldt County, IA, Mitchell County, IA, Sac County, IA, Webster County, IA, Worth County, IA, Wright County, IA

The radar

The Des Moines radar (KDMX), 110 km from the middle of the area, began a volume at 04:47 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

Minneapolis, MN (KMPX), launched 00:00Z, 4.8 hours before the alert went out and 238 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: 1191 J/kg
Mixed-layer CIN: -102 J/kg
Mixed-layer LCL: 1190 m above ground
0-6 km bulk shear: 58 kt
0-1 km storm-relative helicity: 212 m²/s²
0-3 km storm-relative helicity: 230 m²/s²
Significant tornado parameter: 0.8
Supercell composite: 5.2

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
Sep 19, 10:34 PM CDT	Mesoscale Discussion	SPC	Buena Vista, Cherokee, Clay, Dickinson, Emmet, Kossuth and 6 more	116 min
Sep 20, 5:23 PM CDT	Mesoscale Discussion	SPC	Allamakee, Howard, Mitchell, Winneshiek	67 min
Sep 20, 5:42 PM CDT	Severe Thunderstorm Watch	SPC	Allamakee, Cerro Gordo, Chickasaw, Emmet, Floyd, Hancock and 7 more	3 hr
Sep 20, 6:56 PM CDT	Mesoscale Discussion	SPC	Davis, Des Moines, Henry, Jefferson, Lee, Louisa and 4 more	2 hr

Nearby

Mesoscale Discussions in Iowa, 2014 Every mesoscale discussion in 2014

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.