Alert archive / Iowa / Mesoscale Discussions in 2018

Mesoscale Discussion 952

June 30, 20184 states

The Storm Prediction Center issued this mesoscale discussion at Jun 30, 2018, 12:40 PM CDT for 4 states. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued: Jun 30, 2018, 12:40 PM CDT (17:40 UTC)
Expired: Jun 30, 2018, 3:15 PM CDT
In force: 3 hr
Issued by: the Storm Prediction Center
Chance of a watch: 80%

All 67 counties

Buena Vista County, IA, Calhoun County, IA, Carroll County, IA, Cerro Gordo County, IA, Cherokee County, IA, Chickasaw County, IA, Clay County, IA, Crawford County, IA, Dickinson County, IA, Emmet County, IA, Floyd County, IA, Franklin County, IA, Hancock County, IA, Harrison County, IA, Howard County, IA, Humboldt County, IA, Ida County, IA, Kossuth County, IA, Mitchell County, IA, Monona County, IA, O'Brien County, IA, Osceola County, IA, Palo Alto County, IA, Plymouth County, IA, Pocahontas County, IA, Sac County, IA, Sioux County, IA, Webster County, IA, Winnebago County, IA, Woodbury County, IA, Worth County, IA, Wright County, IA, Dodge County, MN, Faribault County, MN, Fillmore County, MN, Freeborn County, MN, Martin County, MN, Mower County, MN, Olmsted County, MN, Steele County, MN, Waseca County, MN, Boone County, NE, Burt County, NE, Butler County, NE, Clay County, NE, Colfax County, NE, Cuming County, NE, Dakota County, NE, Dixon County, NE, Dodge County, NE, Fillmore County, NE, Hall County, NE, Hamilton County, NE, Howard County, NE, Madison County, NE, Merrick County, NE, Nance County, NE, Platte County, NE, Polk County, NE, Saunders County, NE, Seward County, NE, Stanton County, NE, Thurston County, NE, Washington County, NE, Wayne County, NE, York County, NE, Union County, SD

The radar

The Des Moines radar (KDMX), 134 km from the middle of the area, began a volume at 17:42 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

Omaha, NE (KOAX), launched 12:00Z, 5.7 hours before the alert went out and 182 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: 2420 J/kg
Mixed-layer CIN: -83 J/kg
Mixed-layer LCL: 962 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: -36 m²/s²
0-3 km storm-relative helicity: -9 m²/s²
Significant tornado parameter: -0.1
Supercell composite: -0.2

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 30, 1:39 PM CDT	Severe Thunderstorm Watch	SPC	Adair, Adams, Allamakee, Audubon, Boone, Bremer and 46 more	7 hr
Jun 30, 3:40 PM CDT	Mesoscale Discussion	SPC	Audubon, Boone, Butler, Calhoun, Carroll, Cass and 25 more	2 hr
Jun 30, 4:40 PM CDT	Mesoscale Discussion	SPC	Ringgold, Taylor	95 min
Jun 30, 6:09 PM CDT	Mesoscale Discussion	SPC	Fremont, Mills, Montgomery, Page	96 min
Jun 29, 10:57 PM CDT	Mesoscale Discussion	SPC	Aitkin, Benton, Big Stone, Carlton, Cass, Chippewa and 16 more	63 min
Jun 29, 11:56 PM CDT	Severe Thunderstorm Watch	SPC	Aitkin, Benton, Carlton, Cass, Chippewa, Cook and 19 more	5 hr
Jun 30, 3:21 AM CDT	Mesoscale Discussion	SPC	Aitkin, Carlton, Cook, Itasca, Kanabec, Lake and 2 more	114 min
Jun 29, 9:37 PM CDT	Mesoscale Discussion	SPC	Franklin, Furnas, Gosper, Harlan, Kearney, Phelps and 2 more	113 min
Jun 30, 1:35 AM CDT	Mesoscale Discussion	SPC	Antelope, Arthur, Banner, Blaine, Brown, Garden and 12 more	85 min
Jun 30, 2:03 PM CDT	Mesoscale Discussion	SPC	Arthur, Banner, Box Butte, Cheyenne, Dawes, Deuel and 7 more	87 min
Jun 30, 3:03 PM CDT	Severe Thunderstorm Watch	SPC	Banner, Box Butte, Cheyenne, Dawes, Kimball, Morrill and 2 more	7 hr
Jun 30, 3:11 PM CDT	Mesoscale Discussion	SPC	Adams, Boone, Buffalo, Chase, Clay, Custer and 29 more	94 min
Jun 30, 3:26 PM CDT	Severe Thunderstorm Watch	SPC	Adams, Arthur, Blaine, Buffalo, Chase, Cherry and 39 more	8 hr
Jun 30, 5:40 PM CDT	Mesoscale Discussion	SPC	Banner, Box Butte, Cheyenne, Deuel, Kimball, Morrill and 1 more	2 hr
Jun 30, 6:09 PM CDT	Severe Thunderstorm Watch	SPC	Dundy, Hitchcock, Red Willow	7 hr
Jun 29, 8:31 PM CDT	Mesoscale Discussion	SPC	Stanley	29 min

Nearby

Mesoscale Discussions in Iowa, 2018 Mesoscale Discussions in Nebraska, 2018 Mesoscale Discussions in Minnesota, 2018 Every mesoscale discussion in 2018

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.