Alert archive / Iowa / Severe Thunderstorm Watches in 2015
Severe Thunderstorm Watch 504
The Storm Prediction Center issued this severe thunderstorm watch at Sep 6, 2015, 6:02 PM CDT for 4 states. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Sep 6, 2015, 6:02 PM CDT (23:02 UTC)
- Expired
- Sep 7, 2015, 1:00 AM CDT
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 73 counties
Adair County, IA, Adams County, IA, Allamakee County, IA, Audubon County, IA, Black Hawk County, IA, Boone County, IA, Bremer County, IA, Butler County, IA, Calhoun County, IA, Carroll County, IA, Cass County, IA, Cerro Gordo County, IA, Chickasaw County, IA, Clarke County, IA, Crawford County, IA, Dallas County, IA, Fayette County, IA, Floyd County, IA, Franklin County, IA, Fremont 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, Jasper County, IA, Kossuth County, IA, Madison County, IA, Marshall County, IA, Mills County, IA, Mitchell County, IA, Montgomery County, IA, Page County, IA, Pocahontas County, IA, Polk County, IA, Pottawattamie County, IA, Ringgold County, IA, Sac County, IA, Shelby County, IA, Story County, IA, Tama County, IA, Taylor County, IA, Union County, IA, Warren County, IA, Webster County, IA, Winnebago County, IA, Winneshiek County, IA, Worth County, IA, Wright County, IA, Fillmore County, MN, Houston County, MN, Mower County, MN, Atchison County, MO, Holt County, MO, Nodaway County, MO, Worth County, MO, Cass County, NE, Douglas County, NE, Gage County, NE, Jefferson County, NE, Johnson County, NE, Lancaster County, NE, Nemaha County, NE, Otoe County, NE, Pawnee County, NE, Richardson County, NE, Saline County, NE, Sarpy County, NE, Saunders County, NE
The radar
The Des Moines radar (KDMX), 79 km from the middle of the area, began a volume at 23:04 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
- 40%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 60%
- One or more hailstones of 2 inches or more
- 30%
- Six or more combined severe hail and wind reports
- 80%
Warnings issued inside it
21 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 6, 6:05 PM CDT | Severe Thunderstorm Warning | DMX | Calhoun, Humboldt, Pocahontas | 40 min |
| Sep 6, 6:13 PM CDT | Severe Thunderstorm Warning | DMX | Hancock | 47 min |
| Sep 6, 6:25 PM CDT | Severe Thunderstorm Warning | DMX | Calhoun | 35 min |
| Sep 6, 6:30 PM CDT | Severe Thunderstorm Warning | OAX | Shelby | 45 min |
| Sep 6, 6:34 PM CDT | Severe Thunderstorm Warning | OAX | Cass, Lancaster, Sarpy, Saunders | 41 min |
| Sep 6, 6:44 PM CDT | Severe Thunderstorm Warning | OAX | Lancaster | 46 min |
| Sep 6, 6:52 PM CDT | Severe Thunderstorm Warning | DMX | Calhoun, Carroll, Greene | 53 min |
| Sep 6, 6:56 PM CDT | Severe Thunderstorm Warning | OAX | Douglas, Sarpy, Saunders | 49 min |
| Sep 6, 7:14 PM CDT | Severe Thunderstorm Warning | OAX | Cass, Lancaster, Otoe | 46 min |
| Sep 6, 7:19 PM CDT | Severe Thunderstorm Warning | DMX | Cerro Gordo | 26 min |
| Sep 6, 7:30 PM CDT | Severe Thunderstorm Warning | OAX | Gage, Lancaster, Saline | 30 min |
| Sep 6, 7:54 PM CDT | Severe Thunderstorm Warning | DMX | Boone, Greene, Hamilton, Webster | 30 min |
| Sep 6, 7:55 PM CDT | Flash Flood Warning | DMX | Calhoun, Carroll | 6 hr |
| Sep 6, 8:14 PM CDT | Flash Flood Warning | DMX | Boone, Carroll, Greene | 6 hr |
| Sep 6, 9:12 PM CDT | Flash Flood Warning | DMX | Audubon, Boone, Dallas, Greene, Guthrie | 6 hr |
| Sep 6, 9:12 PM CDT | Severe Thunderstorm Warning | DMX | Boone, Polk | 28 min |
| Sep 6, 9:18 PM CDT | Severe Thunderstorm Warning | DMX | Dallas, Guthrie | 27 min |
| Sep 6, 9:24 PM CDT | Severe Thunderstorm Warning | OAX | Cass | 51 min |
| Sep 6, 9:47 PM CDT | Severe Thunderstorm Warning | OAX | Otoe | 28 min |
| Sep 6, 10:00 PM CDT | Flash Flood Warning | DMX | Boone, Dallas | 6 hr |
| Sep 6, 10:05 PM CDT | Severe Thunderstorm Warning | OAX | Fremont | 40 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, 11.0 hours before the alert went out and 213 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.
- Mixed-layer CAPE
- 648 J/kg
- Mixed-layer CIN
- -347 J/kg
- Mixed-layer LCL
- 1274 m above ground
- 0-6 km bulk shear
- 32 kt
- 0-1 km storm-relative helicity
- 387 m²/s²
- 0-3 km storm-relative helicity
- 389 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 6, 2:31 PM CDT | Mesoscale Discussion | SPC | Dickinson, Lyon, O'Brien, Osceola, Sioux | 119 min |
| Sep 6, 5:12 PM CDT | Mesoscale Discussion | SPC | Allamakee, Chickasaw, Howard, Winneshiek | 2 hr |
| Sep 6, 5:26 PM CDT | Mesoscale Discussion | SPC | Audubon, Buena Vista, Calhoun, Carroll, Cass, Cherokee and 28 more | 94 min |
| Sep 5, 7:34 PM CDT | Mesoscale Discussion | SPC | Aitkin, Cass, Crow Wing, Douglas, Hubbard, Itasca and 6 more | 86 min |
| Sep 6, 3:42 PM CDT | Severe Thunderstorm Watch | SPC | Aitkin, Anoka, Benton, Carlton, Carver, Cass and 33 more | 6 hr |
| Sep 6, 6:29 PM CDT | Mesoscale Discussion | SPC | Aitkin, Anoka, Benton, Carlton, Carver, Chippewa and 24 more | 2 hr |
Nearby
Severe Thunderstorm Watches in Iowa, 2015Severe Thunderstorm Watches in Nebraska, 2015Severe Thunderstorm Watches in Missouri, 2015Every severe thunderstorm watch in 2015
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.