Alert archive / Iowa / Severe Thunderstorm Watches in 2018

Severe Thunderstorm Watch 157

June 6, 201847 counties in Iowa; Atchison County, Missouri; 36 counties in Nebraska

The Storm Prediction Center issued this severe thunderstorm watch at Jun 6, 2018, 3:23 PM CDT for 47 counties in Iowa; Atchison County, Missouri; 36 counties in Nebraska. It was in force for 9 hr.

The area

The outline as issued.

The facts

Issued: Jun 6, 2018, 3:23 PM CDT (20:23 UTC)
Expired: Jun 7, 2018, 12:00 AM CDT
In force: 9 hr
Issued by: the Storm Prediction Center
Largest hail expected: 2 in
Strongest gust expected: 60 kt

All 84 counties

Adair County, IA, Adams County, IA, Appanoose County, IA, Audubon County, IA, Boone County, IA, Calhoun County, IA, Carroll County, IA, Cass County, IA, Clarke County, IA, Crawford County, IA, Dallas County, IA, Davis County, IA, Decatur County, IA, Fremont County, IA, Greene County, IA, Grundy County, IA, Guthrie County, IA, Hamilton County, IA, Hardin County, IA, Harrison County, IA, Humboldt County, IA, Jasper County, IA, Lucas County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Marshall County, IA, Mills County, IA, Monona County, IA, Monroe County, IA, Montgomery County, IA, Page County, IA, Pocahontas County, IA, Polk County, IA, Pottawattamie County, IA, Poweshiek County, IA, Ringgold County, IA, Sac County, IA, Shelby County, IA, Story County, IA, Tama County, IA, Taylor County, IA, Union County, IA, Wapello County, IA, Warren County, IA, Wayne County, IA, Webster County, IA, Atchison County, MO, Boone County, NE, Burt County, NE, Butler County, NE, Cass County, NE, Clay County, NE, Colfax County, NE, Cuming County, NE, Dodge County, NE, Douglas County, NE, Fillmore County, NE, Gage County, NE, Greeley County, NE, Hamilton County, NE, Howard County, NE, Jefferson County, NE, Johnson County, NE, Lancaster County, NE, Madison County, NE, Merrick County, NE, Nance County, NE, Nemaha County, NE, Nuckolls County, NE, Otoe County, NE, Pawnee County, NE, Platte County, NE, Polk County, NE, Saline County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE, Sherman County, NE, Stanton County, NE, Thayer County, NE, Valley County, NE, Washington County, NE, York County, NE

The radar

The Omaha radar (KOAX), 8 km from the middle of the area, began a volume at 20:24 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes: 10%
One or more EF2 to EF5 tornadoes: 2%
Ten or more severe wind reports: 70%
One or more gusts of 65 knots or more: 20%
Ten or more severe hail reports: 70%
One or more hailstones of 2 inches or more: 30%
Six or more combined severe hail and wind reports: 90%

Warnings issued inside it

69 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Jun 6, 3:29 PM CDT	Severe Thunderstorm Warning	DMX	Boone, Hamilton, Webster	46 min
Jun 6, 3:50 PM CDT	Severe Thunderstorm Warning	DMX	Calhoun	40 min
Jun 6, 3:51 PM CDT	Severe Thunderstorm Warning	DMX	Hamilton, Webster	54 min
Jun 6, 4:04 PM CDT	Severe Thunderstorm Warning	OAX	Harrison, Monona	41 min
Jun 6, 4:06 PM CDT	Severe Thunderstorm Warning	GID	Merrick, Nance, Polk	39 min
Jun 6, 4:15 PM CDT	Severe Thunderstorm Warning	DMX	Boone, Hamilton, Story, Webster	45 min
Jun 6, 4:22 PM CDT	Severe Thunderstorm Warning	DMX	Calhoun, Carroll, Greene	38 min
Jun 6, 4:33 PM CDT	Tornado Warning	OAX	Burt	27 min
Jun 6, 4:34 PM CDT	Severe Thunderstorm Warning	DMX	Black Hawk, Grundy, Tama	41 min
Jun 6, 4:40 PM CDT	Severe Thunderstorm Warning	DMX	Boone, Greene, Hamilton, Story	50 min
Jun 6, 4:47 PM CDT	Severe Thunderstorm Warning	DMX	Hardin, Marshall, Story	43 min
Jun 6, 4:56 PM CDT	Tornado Warning	OAX	Burt	34 min
Jun 6, 4:59 PM CDT	Severe Thunderstorm Warning	DMX	Carroll, Crawford, Greene	46 min
Jun 6, 5:00 PM CDT	Severe Thunderstorm Warning	DMX	Hamilton, Story	48 min
Jun 6, 5:14 PM CDT	Severe Thunderstorm Warning	DMX	Tama	61 min
Jun 6, 5:19 PM CDT	Severe Thunderstorm Warning	DMX	Jasper, Polk, Story	41 min
Jun 6, 5:22 PM CDT	Severe Thunderstorm Warning	OAX	Boone	38 min
Jun 6, 5:25 PM CDT	Severe Thunderstorm Warning	DMX	Boone, Dallas, Polk	35 min
Jun 6, 5:27 PM CDT	Severe Thunderstorm Warning	OAX	Burt, Cuming, Thurston	48 min
Jun 6, 5:28 PM CDT	Severe Thunderstorm Warning	DMX	Grundy, Hardin, Marshall, Story, Tama	47 min
Jun 6, 5:31 PM CDT	Severe Thunderstorm Warning	OAX	Madison, Platte	29 min
Jun 6, 5:36 PM CDT	Severe Thunderstorm Warning	DMX	Polk	39 min
Jun 6, 5:39 PM CDT	Severe Thunderstorm Warning	DMX	Dallas, Greene, Guthrie	66 min
Jun 6, 5:43 PM CDT	Severe Thunderstorm Warning	DMX	Carroll, Crawford	47 min
Jun 6, 5:47 PM CDT	Severe Thunderstorm Warning	DMX	Marshall, Tama	58 min
Jun 6, 5:57 PM CDT	Severe Thunderstorm Warning	DMX	Boone, Dallas, Greene, Guthrie, Polk	63 min
Jun 6, 5:59 PM CDT	Severe Thunderstorm Warning	OAX	Burt, Cuming, Dodge, Washington	46 min
Jun 6, 6:00 PM CDT	Severe Thunderstorm Warning	OAX	Antelope, Boone, Madison, Platte	45 min
Jun 6, 6:03 PM CDT	Severe Thunderstorm Warning	OAX	Cuming, Stanton	42 min
Jun 6, 6:07 PM CDT	Severe Thunderstorm Warning	DMX	Polk	53 min
Jun 6, 6:08 PM CDT	Severe Thunderstorm Warning	DMX	Jasper, Marshall, Poweshiek, Tama	37 min
Jun 6, 6:19 PM CDT	Flash Flood Warning	OAX	Burt, Cuming	4 hr
Jun 6, 6:26 PM CDT	Severe Thunderstorm Warning	OAX	Colfax, Cuming, Dodge, Stanton	34 min
Jun 6, 6:29 PM CDT	Severe Thunderstorm Warning	DMX	Audubon, Carroll, Crawford	36 min
Jun 6, 6:35 PM CDT	Severe Thunderstorm Warning	OAX	Boone, Platte	25 min
Jun 6, 6:39 PM CDT	Severe Thunderstorm Warning	DMX	Dallas, Madison, Polk, Warren	81 min
Jun 6, 6:43 PM CDT	Severe Thunderstorm Warning	DMX	Jasper, Mahaska, Marion, Poweshiek	62 min
Jun 6, 6:45 PM CDT	Severe Thunderstorm Warning	OAX	Colfax, Cuming, Dodge, Stanton	30 min
Jun 6, 6:57 PM CDT	Severe Thunderstorm Warning	OAX	Colfax, Madison, Platte, Stanton	48 min
Jun 6, 7:11 PM CDT	Flash Flood Warning	OAX	Cuming, Dodge	4 hr
Jun 6, 7:15 PM CDT	Severe Thunderstorm Warning	DMX	Lucas, Mahaska, Marion, Monroe, Wapello, Warren	60 min
Jun 6, 7:22 PM CDT	Severe Thunderstorm Warning	OAX	Cuming, Madison, Pierce, Stanton, Wayne	38 min
Jun 6, 7:32 PM CDT	Severe Thunderstorm Warning	OAX	Butler, Colfax, Dodge, Platte, Saunders	43 min
Jun 6, 7:45 PM CDT	Severe Thunderstorm Warning	DMX	Adair, Audubon, Cass, Guthrie	60 min
Jun 6, 7:46 PM CDT	Severe Thunderstorm Warning	OAX	Platte	29 min
Jun 6, 7:56 PM CDT	Severe Thunderstorm Warning	OAX	Butler, Saunders	49 min
Jun 6, 7:59 PM CDT	Severe Thunderstorm Warning	OAX	Monona	46 min
Jun 6, 8:11 PM CDT	Severe Thunderstorm Warning	GID	Merrick, Nance, Polk	49 min
Jun 6, 8:18 PM CDT	Severe Thunderstorm Warning	DMX	Appanoose, Davis, Wapello	29 min
Jun 6, 8:41 PM CDT	Severe Thunderstorm Warning	OAX	Butler, Lancaster, Saunders, Seward	34 min
Jun 6, 8:46 PM CDT	Severe Thunderstorm Warning	OAX	Boone, Platte	29 min
Jun 6, 8:55 PM CDT	Severe Thunderstorm Warning	DMX	Adair, Adams, Cass, Union	50 min
Jun 6, 9:18 PM CDT	Severe Thunderstorm Warning	GID	Merrick, Nance	42 min
Jun 6, 9:21 PM CDT	Severe Thunderstorm Warning	GID	Greeley	39 min
Jun 6, 9:28 PM CDT	Flash Flood Warning	OAX	Boone, Platte	3 hr
Jun 6, 9:30 PM CDT	Severe Thunderstorm Warning	OAX	Boone	30 min
Jun 6, 9:39 PM CDT	Severe Thunderstorm Warning	OAX	Pottawattamie	14 min
Jun 6, 9:53 PM CDT	Severe Thunderstorm Warning	DMX	Dallas, Polk	22 min
Jun 6, 9:56 PM CDT	Severe Thunderstorm Warning	DMX	Adair, Audubon, Cass, Guthrie	28 min
Jun 6, 10:06 PM CDT	Severe Thunderstorm Warning	GID	Nance	22 min
Jun 6, 10:07 PM CDT	Severe Thunderstorm Warning	OAX	Mills, Pottawattamie	23 min
Jun 6, 10:18 PM CDT	Severe Thunderstorm Warning	OAX	Cass, Sarpy	27 min
Jun 6, 10:22 PM CDT	Severe Thunderstorm Warning	OAX	Mills, Pottawattamie	23 min
Jun 6, 10:41 PM CDT	Flash Flood Warning	GID	Merrick, Nance	6 hr
Jun 6, 11:13 PM CDT	Severe Thunderstorm Warning	OAX	Fremont	32 min
Jun 6, 11:21 PM CDT	Severe Thunderstorm Warning	EAX	Atchison	39 min
Jun 6, 11:24 PM CDT	Severe Thunderstorm Warning	OAX	Fremont	36 min
Jun 6, 11:54 PM CDT	Severe Thunderstorm Warning	EAX	Atchison, Holt	51 min
Jun 6, 11:57 PM CDT	Severe Thunderstorm Warning	OAX	Johnson, Nemaha, Pawnee, Richardson	33 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 8.4 hours before the alert went out and 9 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: 2519 J/kg
Mixed-layer CIN: -119 J/kg
Mixed-layer LCL: 1071 m above ground
0-6 km bulk shear: 8 kt
0-1 km storm-relative helicity: 66 m²/s²
0-3 km storm-relative helicity: 88 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 6, 2:22 PM CDT	Mesoscale Discussion	SPC	Adair, Adams, Audubon, Boone, Buena Vista, Calhoun and 32 more	113 min
Jun 6, 6:20 PM CDT	Mesoscale Discussion	SPC	Adair, Adams, Audubon, Benton, Boone, Calhoun and 35 more	85 min
Jun 6, 3:49 PM CDT	Mesoscale Discussion	SPC	Arthur, Chase, Cheyenne, Deuel, Dundy, Frontier and 13 more	86 min
Jun 6, 5:46 PM CDT	Severe Thunderstorm Watch	SPC	Arthur, Banner, Box Butte, Chase, Cherry, Cheyenne and 19 more	8 hr

Nearby

Severe Thunderstorm Watches in Iowa, 2018 Severe Thunderstorm Watches in Nebraska, 2018 Severe Thunderstorm Watches in Missouri, 2018 Every severe thunderstorm watch 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.