Alert archive / Iowa / Severe Thunderstorm Watches in 2017
Severe Thunderstorm Watch 219
The Storm Prediction Center issued this severe thunderstorm watch at May 15, 2017, 11:54 PM CDT for 4 states. It was in force for 3 hr.
The area
The outline as issued.
The facts
- Issued
- May 15, 2017, 11:54 PM CDT (04:54 UTC)
- Expired
- May 16, 2017, 3:17 AM CDT
- In force
- 3 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 23 counties
Cherokee County, IA, Clay County, IA, Dickinson County, IA, Lyon County, IA, O'Brien County, IA, Osceola County, IA, Plymouth County, IA, Sioux County, IA, Woodbury County, IA, Cottonwood County, MN, Jackson County, MN, Nobles County, MN, Rock County, MN, Dakota County, NE, Dixon County, NE, Bon Homme County, SD, Clay County, SD, Hutchinson County, SD, Lincoln County, SD, Minnehaha County, SD, Turner County, SD, Union County, SD, Yankton County, SD
The radar
The Sioux Falls radar (KFSD), 34 km from the middle of the area, began a volume at 04:54 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
- 5%
- One or more EF2 to EF5 tornadoes
- 2%
- Ten or more severe wind reports
- 20%
- One or more gusts of 65 knots or more
- 5%
- Ten or more severe hail reports
- 30%
- One or more hailstones of 2 inches or more
- 30%
- Six or more combined severe hail and wind reports
- 60%
Warnings issued inside it
1 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 16, 1:59 AM CDT | Severe Thunderstorm Warning | FSD | Murray, Nobles | 27 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 00:00Z, 4.9 hours before the alert went out and 220 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
- 1237 J/kg
- Mixed-layer CIN
- -105 J/kg
- Mixed-layer LCL
- 2394 m above ground
- 0-6 km bulk shear
- 41 kt
- 0-1 km storm-relative helicity
- 78 m²/s²
- 0-3 km storm-relative helicity
- 246 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 3.4
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 15, 7:19 PM CDT | Mesoscale Discussion | SPC | Allamakee, Black Hawk, Bremer, Buchanan, Butler, Cerro Gordo and 26 more | 56 min |
| May 15, 8:50 PM CDT | Mesoscale Discussion | SPC | Clay, Dickinson, Emmet, Kossuth, Mitchell, Osceola and 3 more | 115 min |
| May 15, 9:48 PM CDT | Severe Thunderstorm Watch | SPC | Allamakee, Howard, Mitchell, Winneshiek | 5 hr |
| May 16, 2:13 AM CDT | Mesoscale Discussion | SPC | Buena Vista, Cherokee, Clay, Dickinson, Emmet, Hancock and 12 more | 92 min |
| May 16, 3:58 PM CDT | Mesoscale Discussion | SPC | Adams, Audubon, Buena Vista, Calhoun, Carroll, Cass and 23 more | 2 hr |
| May 16, 4:57 PM CDT | Severe Thunderstorm Watch | SPC | Adair, Adams, Audubon, Buena Vista, Calhoun, Carroll and 23 more | 7 hr |
| May 16, 3:32 PM CDT | Mesoscale Discussion | SPC | Anoka, Blue Earth, Brown, Carver, Chisago, Dakota and 28 more | 88 min |
| May 16, 4:08 PM CDT | Severe Thunderstorm Watch | SPC | Anoka, Blue Earth, Brown, Carver, Chisago, Dakota and 16 more | 4 hr |
| May 15, 7:34 PM CDT | Mesoscale Discussion | SPC | Banner, Box Butte, Dawes, Morrill, Scotts Bluff, Sheridan and 1 more | 56 min |
| May 15, 7:41 PM CDT | Mesoscale Discussion | SPC | Burt, Butler, Colfax, Cuming, Dodge, Madison and 9 more | 3 hr |
| May 15, 10:53 PM CDT | Mesoscale Discussion | SPC | Banner, Box Butte, Dawes, Morrill, Scotts Bluff, Sheridan and 1 more | 67 min |
| May 16, 2:16 PM CDT | Mesoscale Discussion | SPC | Banner, Cheyenne, Kimball, Scotts Bluff, Sioux | 119 min |
| May 16, 5:47 PM CDT | Mesoscale Discussion | SPC | Arthur, Blaine, Box Butte, Brown, Chase, Cherry and 21 more | 88 min |
Nearby
Severe Thunderstorm Watches in Iowa, 2017Severe Thunderstorm Watches in South Dakota, 2017Severe Thunderstorm Watches in Minnesota, 2017Every severe thunderstorm watch in 2017
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.