Alert archive / South Dakota / Mesoscale Discussions in 2011

Mesoscale Discussion 1616

July 14, 2011Sioux County, North Dakota; 17 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Jul 14, 2011, 3:55 PM CDT for Sioux County, North Dakota; 17 counties in South Dakota. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jul 14, 2011, 3:55 PM CDT (20:55 UTC)
Expired: Jul 14, 2011, 6:00 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center

Counties Sioux County, ND, Beadle County, SD, Brown County, SD, Campbell County, SD, Corson County, SD, Dewey County, SD, Edmunds County, SD, Faulk County, SD, Hand County, SD, Hyde County, SD, McPherson County, SD, Meade County, SD, Perkins County, SD, Potter County, SD, Spink County, SD, Sully County, SD, Walworth County, SD, Ziebach County, SD

The radar

The Bismarck radar (KBIS), 171 km from the middle of the area, began a volume at 20:55 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.

Tornado Watch 644Jul 14, 5:35 PM CDT

The nearest sounding before it

Bismarck Municip, ND (KBIS), launched 12:00Z, 8.9 hours before the alert went out and 172 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: 9 J/kg
Mixed-layer CIN: -181 J/kg
Mixed-layer LCL: 468 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 107 m²/s²
0-3 km storm-relative helicity: 174 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.3

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
Jul 14, 5:33 PM CDT	Tornado Watch	SPC	Adams, Billings, Bowman, Burleigh, Emmons, Golden Valley and 10 more	7 hr

Nearby

Mesoscale Discussions in South Dakota, 2011 Mesoscale Discussions in North Dakota, 2011 Every mesoscale discussion in 2011

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.