Alert archive / Iowa / Mesoscale Discussions in 2018

Mesoscale Discussion 1008

July 4, 201841 counties in Iowa; Freeborn County, Mower County, Minnesota; 5 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Jul 4, 2018, 10:27 AM CDT for 41 counties in Iowa; Freeborn County, Mower County, Minnesota; 5 counties in Nebraska. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Jul 4, 2018, 10:27 AM CDT (15:27 UTC)
Expired
Jul 4, 2018, 12:30 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
20%
All 48 counties

Audubon County, IA, Black Hawk County, IA, Boone County, IA, Bremer County, IA, Buena Vista County, IA, Butler County, IA, Calhoun County, IA, Carroll County, IA, Cerro Gordo County, IA, Chickasaw County, IA, Clay County, IA, Crawford County, IA, Emmet County, IA, Fayette County, IA, Floyd County, IA, Franklin County, IA, Greene County, IA, Grundy County, IA, Guthrie County, IA, Hamilton County, IA, Hancock County, IA, Hardin County, IA, Harrison County, IA, Howard County, IA, Humboldt County, IA, Ida County, IA, Kossuth County, IA, Marshall County, IA, Mitchell County, IA, Monona County, IA, Palo Alto County, IA, Pocahontas County, IA, Sac County, IA, Shelby County, IA, Story County, IA, Webster County, IA, Winnebago County, IA, Winneshiek County, IA, Woodbury County, IA, Worth County, IA, Wright County, IA, Freeborn County, MN, Mower County, MN, Burt County, NE, Cuming County, NE, Dodge County, NE, Thurston County, NE, Washington County, NE

The radar

The Des Moines radar (KDMX), 114 km from the middle of the area, began a volume at 15:30 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

Omaha, NE (KOAX), launched 12:00Z, 3.5 hours before the alert went out and 210 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, Omaha, NE at 12:00Z on 2018-07-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 762 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, Omaha, NE at 12:00Z on 2018-07-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -53 square meters per square second.193958Sfc1 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
762 J/kg
Mixed-layer CIN
-257 J/kg
Mixed-layer LCL
1648 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
-53 m²/s²
0-3 km storm-relative helicity
25 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

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.

IssuedProductOfficeCountiesLasted
Jul 4, 9:56 AM CDTMesoscale DiscussionSPCAllamakee, Chickasaw, Howard, Mitchell, Winneshiek2 hr
Jul 4, 2:01 PM CDTMesoscale DiscussionSPCMonona, Plymouth, Woodbury119 min
Jul 4, 5:35 PM CDTMesoscale DiscussionSPCPlymouth115 min
Jul 4, 12:49 AM CDTMesoscale DiscussionSPCClay, Marshall, Norman, Pennington, Polk, Red Lake and 1 more116 min
Jul 4, 1:34 AM CDTSevere Thunderstorm WatchSPCBecker, Beltrami, Clay, Clearwater, Hubbard, Kittson and 11 more7 hr
Jul 4, 3:14 AM CDTMesoscale DiscussionSPCBig Stone, Traverse91 min
Jul 4, 7:10 AM CDTMesoscale DiscussionSPCAitkin, Carlton, Cass, Crow Wing, Itasca, Koochiching and 1 more95 min
Jul 3, 7:36 PM CDTMesoscale DiscussionSPCArthur, Banner, Chase, Cheyenne, Deuel, Dundy and 11 more54 min
Jul 4, 2:51 PM CDTMesoscale DiscussionSPCArthur, Banner, Box Butte, Cheyenne, Deuel, Garden and 7 more54 min

Nearby

Mesoscale Discussions in Iowa, 2018Mesoscale Discussions in Nebraska, 2018Mesoscale Discussions in Minnesota, 2018Every 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.