Alert archive / South Dakota / Mesoscale Discussions in 2007

Mesoscale Discussion 1639

August 4, 20074 states

The Storm Prediction Center issued this mesoscale discussion at Aug 4, 2007, 1:49 AM CDT for 4 states. It was in force for 86 min.

The area

The outline as issued.

The facts

Issued: Aug 4, 2007, 1:49 AM CDT (06:49 UTC)
Expired: Aug 4, 2007, 3:15 AM CDT
In force: 86 min
Issued by: the Storm Prediction Center

All 49 counties

Buena Vista County, IA, Cherokee County, IA, Clay County, IA, Dickinson County, IA, Ida County, IA, Lyon County, IA, Monona County, IA, O'Brien County, IA, Osceola County, IA, Plymouth County, IA, Sac County, IA, Sioux County, IA, Woodbury County, IA, Jackson County, MN, Lincoln County, MN, Murray County, MN, Nobles County, MN, Pipestone County, MN, Rock County, MN, Burt County, NE, Cedar County, NE, Cuming County, NE, Dakota County, NE, Dixon County, NE, Knox County, NE, Thurston County, NE, Wayne County, NE, Aurora County, SD, Beadle County, SD, Bon Homme County, SD, Brookings County, SD, Charles Mix County, SD, Clay County, SD, Davison County, SD, Douglas County, SD, Hanson County, SD, Hutchinson County, SD, Jerauld County, SD, Kingsbury County, SD, Lake County, SD, Lincoln County, SD, McCook County, SD, Miner County, SD, Minnehaha County, SD, Moody County, SD, Sanborn County, SD, Turner County, SD, Union County, SD, Yankton County, SD

The radar

The Sioux Falls radar (KFSD), 30 km from the middle of the area, began a volume at 06:51 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

Aberdeen, SD (KABR), launched 00:00Z, 6.8 hours before the alert went out and 197 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1787 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: -42 m²/s²
0-3 km storm-relative helicity: -15 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
Aug 4, 1:01 PM CDT	Mesoscale Discussion	SPC	Des Moines, Henry, Jefferson, Lee, Louisa, Van Buren	2 hr
Aug 4, 2:51 PM CDT	Mesoscale Discussion	SPC	Audubon, Boone, Buena Vista, Calhoun, Carroll, Cherokee and 16 more	114 min
Aug 4, 3:55 PM CDT	Severe Thunderstorm Watch	SPC	Adair, Adams, Appanoose, Audubon, Boone, Buena Vista and 50 more	6 hr
Aug 4, 6:09 PM CDT	Mesoscale Discussion	SPC	Adair, Adams, Appanoose, Audubon, Boone, Buena Vista and 40 more	66 min
Aug 3, 8:02 PM CDT	Mesoscale Discussion	SPC	Antelope, Blaine, Boyd, Brown, Cherry, Garfield and 8 more	118 min
Aug 4, 5:06 PM CDT	Mesoscale Discussion	SPC	Chase, Custer, Dawson, Dundy, Frontier, Garfield and 12 more	114 min
Aug 4, 5:46 PM CDT	Severe Thunderstorm Watch	SPC	Blaine, Buffalo, Custer, Dawson, Frontier, Garfield and 12 more	4 hr

Nearby

Mesoscale Discussions in South Dakota, 2007 Mesoscale Discussions in Iowa, 2007 Mesoscale Discussions in Nebraska, 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.