Alert archive / Iowa / Severe Thunderstorm Watches in 2011

Severe Thunderstorm Watch 559

June 26, 201146 counties in Iowa; 32 counties in Nebraska

The Storm Prediction Center issued this severe thunderstorm watch at Jun 26, 2011, 4:56 PM CDT for 46 counties in Iowa; 32 counties in Nebraska. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued: Jun 26, 2011, 4:56 PM CDT (21:56 UTC)
Expired: Jun 27, 2011, 12:00 AM CDT
In force: 7 hr
Issued by: the Storm Prediction Center
Largest hail expected: 3 in
Strongest gust expected: 70 kt

All 78 counties

Adair County, IA, Adams County, IA, Appanoose County, IA, Audubon County, IA, Black Hawk 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, 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, 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, Antelope County, NE, Boone County, NE, Burt County, NE, Butler County, NE, Cass County, NE, Cedar County, NE, Colfax County, NE, Cuming County, NE, Dodge County, NE, Douglas County, NE, Greeley County, NE, Hamilton County, NE, Howard County, NE, Knox County, NE, Lancaster County, NE, Madison County, NE, Merrick County, NE, Nance County, NE, Otoe County, NE, Pierce County, NE, Platte County, NE, Polk County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE, Sherman County, NE, Stanton County, NE, Thurston County, NE, Valley County, NE, Washington County, NE, Wayne County, NE, York County, NE

The radar

The Omaha radar (KOAX), 42 km from the middle of the area, began a volume at 21:58 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: 20%
One or more EF2 to EF5 tornadoes: 5%
Ten or more severe wind reports: 60%
One or more gusts of 65 knots or more: 50%
Ten or more severe hail reports: 90%
One or more hailstones of 2 inches or more: 80%
Six or more combined severe hail and wind reports: 95%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
Jun 26, 4:57 PM CDT	Flash Flood Warning	DMX	Adair, Adams, Madison, Union	6 hr
Jun 26, 5:11 PM CDT	Severe Thunderstorm Warning	OAX	Mills, Montgomery, Pottawattamie	30 min
Jun 26, 5:33 PM CDT	Severe Thunderstorm Warning	GID	Greeley, Howard, Nance, Sherman, Valley	42 min
Jun 26, 5:39 PM CDT	Severe Thunderstorm Warning	OAX	Antelope, Boone	51 min
Jun 26, 5:40 PM CDT	Flash Flood Warning	DMX	Clarke, Lucas	6 hr
Jun 26, 5:46 PM CDT	Severe Thunderstorm Warning	OAX	Antelope, Knox, Pierce	44 min
Jun 26, 5:47 PM CDT	Severe Thunderstorm Warning	DMX	Lucas, Monroe	43 min
Jun 26, 5:56 PM CDT	Severe Thunderstorm Warning	OAX	Colfax, Cuming, Dodge	49 min
Jun 26, 6:07 PM CDT	Severe Thunderstorm Warning	DMX	Adair, Madison	38 min
Jun 26, 6:12 PM CDT	Severe Thunderstorm Warning	OAX	Boone, Madison, Platte, Stanton	48 min
Jun 26, 6:13 PM CDT	Severe Thunderstorm Warning	GID	Greeley, Howard, Merrick, Nance	62 min
Jun 26, 6:20 PM CDT	Severe Thunderstorm Warning	DMX	Appanoose	40 min
Jun 26, 6:28 PM CDT	Severe Thunderstorm Warning	OAX	Cedar, Madison, Pierce, Stanton, Wayne	47 min
Jun 26, 6:33 PM CDT	Severe Thunderstorm Warning	DMX	Monroe	42 min
Jun 26, 6:37 PM CDT	Severe Thunderstorm Warning	OAX	Colfax, Cuming, Dodge, Madison, Platte, Stanton	38 min
Jun 26, 6:54 PM CDT	Severe Thunderstorm Warning	DMX	Davis, Wapello	51 min
Jun 26, 7:02 PM CDT	Severe Thunderstorm Warning	DMX	Appanoose	28 min
Jun 26, 7:08 PM CDT	Severe Thunderstorm Warning	OAX	Burt, Colfax, Cuming, Dodge, Thurston, Washington and 1 more	52 min
Jun 26, 7:12 PM CDT	Severe Thunderstorm Warning	OAX	Butler, Colfax, Dodge, Platte, Saunders	48 min
Jun 26, 7:19 PM CDT	Severe Thunderstorm Warning	DMX	Sac	18 min
Jun 26, 7:22 PM CDT	Severe Thunderstorm Warning	OAX	Monona	53 min
Jun 26, 7:31 PM CDT	Severe Thunderstorm Warning	OAX	Butler, Lancaster, Seward	44 min
Jun 26, 7:33 PM CDT	Severe Thunderstorm Warning	OAX	Harrison, Monona, Pottawattamie, Shelby	42 min
Jun 26, 7:44 PM CDT	Severe Thunderstorm Warning	OAX	Butler, Dodge, Lancaster, Saunders	36 min
Jun 26, 7:45 PM CDT	Severe Thunderstorm Warning	DMX	Carroll, Crawford, Sac	60 min
Jun 26, 7:54 PM CDT	Tornado Warning	OAX	Harrison, Monona	23 min
Jun 26, 7:55 PM CDT	Tornado Warning	OAX	Butler, Seward	23 min
Jun 26, 8:06 PM CDT	Severe Thunderstorm Warning	OAX	Cass, Dodge, Douglas, Lancaster, Sarpy, Saunders and 1 more	39 min
Jun 26, 8:07 PM CDT	Severe Thunderstorm Warning	OAX	Harrison, Monona, Pottawattamie, Shelby	38 min
Jun 26, 8:09 PM CDT	Flash Flood Warning	DMX	Appanoose, Davis	6 hr
Jun 26, 8:15 PM CDT	Severe Thunderstorm Warning	OAX	Gage, Lancaster, Saline, Seward	34 min
Jun 26, 8:21 PM CDT	Severe Thunderstorm Warning	DMX	Calhoun, Carroll, Sac	54 min
Jun 26, 8:22 PM CDT	Severe Thunderstorm Warning	OAX	Mills, Pottawattamie	38 min
Jun 26, 8:23 PM CDT	Severe Thunderstorm Warning	DMX	Adair, Audubon, Cass, Guthrie	67 min
Jun 26, 8:33 PM CDT	Severe Thunderstorm Warning	OAX	Mills, Pottawattamie	42 min
Jun 26, 8:41 PM CDT	Severe Thunderstorm Warning	OAX	Mills, Montgomery, Pottawattamie, Shelby	49 min
Jun 26, 8:41 PM CDT	Severe Thunderstorm Warning	OAX	Gage, Jefferson, Johnson, Lancaster, Otoe, Saline	64 min
Jun 26, 8:47 PM CDT	Severe Thunderstorm Warning	DMX	Calhoun, Greene, Webster	58 min
Jun 26, 8:50 PM CDT	Tornado Warning	DMX	Carroll, Greene	40 min
Jun 26, 8:53 PM CDT	Severe Thunderstorm Warning	OAX	Fremont, Mills, Montgomery	52 min
Jun 26, 9:07 PM CDT	Severe Thunderstorm Warning	DMX	Adair, Dallas, Madison	38 min
Jun 26, 9:20 PM CDT	Severe Thunderstorm Warning	DMX	Boone, Hamilton, Story, Webster	25 min
Jun 26, 9:31 PM CDT	Severe Thunderstorm Warning	OAX	Fremont, Mills, Montgomery, Page	44 min
Jun 26, 9:34 PM CDT	Severe Thunderstorm Warning	DMX	Jasper, Madison, Marion, Polk, Story, Warren	41 min
Jun 26, 9:43 PM CDT	Severe Thunderstorm Warning	DMX	Boone, Hamilton, Hardin, Story	47 min
Jun 26, 9:47 PM CDT	Severe Thunderstorm Warning	OAX	Johnson, Nemaha, Otoe, Richardson	43 min
Jun 26, 9:56 PM CDT	Severe Thunderstorm Warning	DMX	Adams, Clarke, Decatur, Lucas, Ringgold, Taylor and 1 more	64 min
Jun 26, 10:06 PM CDT	Severe Thunderstorm Warning	DMX	Grundy, Hardin, Marshall, Tama	54 min
Jun 26, 10:08 PM CDT	Severe Thunderstorm Warning	DMX	Jasper, Mahaska, Marion, Poweshiek, Warren	67 min
Jun 26, 10:29 PM CDT	Severe Thunderstorm Warning	DMX	Appanoose	46 min
Jun 26, 10:42 PM CDT	Flash Flood Warning	DMX	Warren	2 hr
Jun 26, 10:44 PM CDT	Severe Thunderstorm Warning	DMX	Appanoose, Decatur, Lucas, Monroe, Ringgold, Wapello and 1 more	46 min
Jun 26, 11:16 PM CDT	Severe Thunderstorm Warning	DMX	Appanoose, Davis	44 min
Jun 26, 11:30 PM CDT	Severe Thunderstorm Warning	GID	Greeley, Valley	45 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, 9.9 hours before the alert went out and 42 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: 859 m above ground
0-6 km bulk shear: 47 kt
0-1 km storm-relative helicity: 26 m²/s²
0-3 km storm-relative helicity: 38 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 26, 6:16 AM CDT	Mesoscale Discussion	SPC	Audubon, Cass, Cherokee, Crawford, Fremont, Harrison and 10 more	59 min
Jun 26, 3:09 PM CDT	Mesoscale Discussion	SPC	Fremont, Mills, Montgomery, Page, Pottawattamie	2 hr
Jun 26, 6:22 PM CDT	Mesoscale Discussion	SPC	Des Moines, Henry, Jefferson, Lee, Van Buren	83 min
Jun 25, 8:14 PM CDT	Severe Thunderstorm Watch	SPC	Brown, Cherry, Keya Paha, Rock, Sheridan	6 hr
Jun 25, 11:27 PM CDT	Mesoscale Discussion	SPC	Brown, Cherry, Keya Paha	63 min
Jun 26, 6:08 AM CDT	Mesoscale Discussion	SPC	Cherry, Keya Paha	97 min
Jun 26, 10:44 AM CDT	Mesoscale Discussion	SPC	Brown, Cherry, Grant, Hooker, Keya Paha, Sheridan and 1 more	2 hr
Jun 26, 1:03 PM CDT	Severe Thunderstorm Watch	SPC	Blaine, Boyd, Brown, Cherry, Garfield, Grant and 8 more	7 hr
Jun 26, 2:30 PM CDT	Mesoscale Discussion	SPC	Antelope, Banner, Blaine, Boone, Box Butte, Boyd and 22 more	2 hr

Nearby

Severe Thunderstorm Watches in Iowa, 2011 Severe Thunderstorm Watches in Nebraska, 2011 Every severe thunderstorm watch 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.