Alert archive / South Dakota / Mesoscale Discussions in 2011

Mesoscale Discussion 1771

July 28, 2011Carter County, Montana; 14 counties in North Dakota; 16 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Jul 28, 2011, 1:05 PM MDT for Carter County, Montana; 14 counties in North Dakota; 16 counties in South Dakota. It was in force for 115 min.

The area

The outline as issued.

The facts

Issued
Jul 28, 2011, 1:05 PM MDT (19:05 UTC)
Expired
Jul 28, 2011, 3:00 PM MDT
In force
115 min
Issued by
the Storm Prediction Center
All 31 counties

Carter County, MT, Adams County, ND, Barnes County, ND, Bowman County, ND, Cass County, ND, Dickey County, ND, Griggs County, ND, LaMoure County, ND, Logan County, ND, McIntosh County, ND, Ransom County, ND, Sargent County, ND, Slope County, ND, Steele County, ND, Stutsman County, ND, Brown County, SD, Butte County, SD, Campbell County, SD, Corson County, SD, Dewey County, SD, Edmunds County, SD, Faulk County, SD, Harding County, SD, Lawrence County, SD, McPherson County, SD, Meade County, SD, Perkins County, SD, Potter County, SD, Sully County, SD, Walworth County, SD, Ziebach County, SD

The radar

The Bismarck radar (KBIS), 108 km from the middle of the area, began a volume at 19:07 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.

The nearest sounding before it

Bismarck Municip, ND (KBIS), launched 12:00Z, 7.1 hours before the alert went out and 109 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-pSkew-T log-p diagram, Bismarck Municip, ND at 12:00Z on 2011-07-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 135 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Bismarck Municip, ND at 12:00Z on 2011-07-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 41 square meters per square second.1939587897117Sfc1 km3 km6 km9 kmRMLM
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
135 J/kg
Mixed-layer CIN
-110 J/kg
Mixed-layer LCL
1472 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
41 m²/s²
0-3 km storm-relative helicity
43 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.

IssuedProductOfficeCountiesLasted
Jul 27, 6:09 PM MDTMesoscale DiscussionSPCDewey, Haakon, Jackson, Jones, Meade, Pennington and 2 more2 hr
Jul 28, 2:31 PM MDTSevere Thunderstorm WatchSPCBuffalo, Butte, Campbell, Corson, Custer, Dewey and 21 more5 hr
Jul 28, 5:19 PM MDTMesoscale DiscussionSPCBuffalo, Butte, Dewey, Haakon, Hughes, Hyde and 9 more86 min

Nearby

Mesoscale Discussions in South Dakota, 2011Mesoscale Discussions in North Dakota, 2011Mesoscale Discussions in Montana, 2011Every 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.