Alert archive / South Dakota / Mesoscale Discussions in 2007

Mesoscale Discussion 831

May 18, 20075 counties in North Dakota; 6 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at May 18, 2007, 4:47 PM MDT for 5 counties in North Dakota; 6 counties in South Dakota. It was in force for 88 min.

The area

The outline as issued.

The facts

Issued: May 18, 2007, 4:47 PM MDT (22:47 UTC)
Expired: May 18, 2007, 6:15 PM MDT
In force: 88 min
Issued by: the Storm Prediction Center

Counties Adams County, ND, Grant County, ND, Hettinger County, ND, Morton County, ND, Sioux County, ND, Butte County, SD, Corson County, SD, Dewey County, SD, Meade County, SD, Perkins County, SD, Ziebach County, SD

The radar

The Bismarck radar (KBIS), 152 km from the middle of the area, began a volume at 22:49 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

Bismarck Municip, ND (KBIS), launched 12:00Z, 10.8 hours before the alert went out and 155 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: 362 J/kg
Mixed-layer CIN: -435 J/kg
Mixed-layer LCL: 1771 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 96 m²/s²
0-3 km storm-relative helicity: 89 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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
May 18, 2:26 PM MDT	Mesoscale Discussion	SPC	Benson, Billings, Bottineau, Burke, Cavalier, Divide and 19 more	64 min
May 18, 2:43 PM MDT	Severe Thunderstorm Watch	SPC	Barnes, Benson, Bottineau, Burke, Burleigh, Cass and 32 more	7 hr

Nearby

Mesoscale Discussions in South Dakota, 2007 Mesoscale Discussions in North Dakota, 2007 Every mesoscale discussion in 2007

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.