Alert archive / Iowa / Tornado Watches in 2015
Tornado Watch 156
The Storm Prediction Center issued this tornado watch at May 10, 2015, 10:46 AM CDT for 4 states. It was in force for 8 hr.
The area
The outline as issued.
The facts
- Issued
- May 10, 2015, 10:46 AM CDT (15:46 UTC)
- Expired
- May 10, 2015, 7:04 PM CDT
- In force
- 8 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 75 counties
Adair County, IA, Audubon County, IA, Buena Vista County, IA, Calhoun County, IA, Carroll County, IA, Cass County, IA, Cherokee County, IA, Clay County, IA, Crawford County, IA, Dickinson County, IA, Emmet County, IA, Greene County, IA, Guthrie County, IA, Harrison County, IA, Ida County, IA, Lyon County, IA, Monona County, IA, O'Brien County, IA, Osceola County, IA, Palo Alto County, IA, Plymouth County, IA, Pocahontas County, IA, Pottawattamie County, IA, Sac County, IA, Shelby County, IA, Sioux County, IA, Woodbury County, IA, Cottonwood County, MN, Jackson County, MN, Lincoln County, MN, Lyon County, MN, Murray County, MN, Nobles County, MN, Pipestone County, MN, Rock County, MN, Antelope County, NE, Burt County, NE, Butler County, NE, Cedar County, NE, Colfax County, NE, Cuming County, NE, Dakota County, NE, Dixon County, NE, Dodge County, NE, Douglas County, NE, Knox County, NE, Madison County, NE, Pierce County, NE, Platte County, NE, Sarpy County, NE, Saunders County, NE, Stanton County, NE, Thurston County, NE, Washington County, NE, Wayne County, NE, Aurora County, SD, Bon Homme County, SD, Brookings County, SD, Clay County, SD, Davison County, SD, Douglas County, SD, Hanson County, SD, Hutchinson County, SD, Jerauld County, SD, Kingsbury County, SD, Lake County, SD, Lincoln County, SD, McCook County, SD, Miner County, SD, Minnehaha County, SD, Moody County, SD, Sanborn County, SD, Turner County, SD, Union County, SD, Yankton County, SD
The radar
The Sioux Falls radar (KFSD), 49 km from the middle of the area, began a volume at 15:48 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
- 60%
- One or more EF2 to EF5 tornadoes
- 20%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 5%
- Ten or more severe hail reports
- 60%
- One or more hailstones of 2 inches or more
- 10%
- Six or more combined severe hail and wind reports
- 95%
Warnings issued inside it
18 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 10, 10:55 AM CDT | Tornado Warning | FSD | Davison, Douglas, Hutchinson | 35 min |
| May 10, 11:23 AM CDT | Tornado Warning | FSD | Davison, Hanson, Hutchinson | 37 min |
| May 10, 11:55 AM CDT | Tornado Warning | FSD | Davison, Hanson, Sanborn | 35 min |
| May 10, 12:27 PM CDT | Severe Thunderstorm Warning | FSD | Davison, Hanson, Miner, Sanborn | 33 min |
| May 10, 12:28 PM CDT | Tornado Warning | FSD | Davison, Hanson, Miner, Sanborn | 32 min |
| May 10, 1:34 PM CDT | Severe Thunderstorm Warning | OAX | Harrison, Pottawattamie | 41 min |
| May 10, 1:34 PM CDT | Severe Thunderstorm Warning | OAX | Cedar, Wayne | 26 min |
| May 10, 1:40 PM CDT | Severe Thunderstorm Warning | FSD | Dixon | 35 min |
| May 10, 1:53 PM CDT | Severe Thunderstorm Warning | OAX | Harrison, Monona | 37 min |
| May 10, 1:57 PM CDT | Severe Thunderstorm Warning | FSD | Hutchinson, McCook, Turner | 33 min |
| May 10, 2:02 PM CDT | Severe Thunderstorm Warning | FSD | Dixon | 28 min |
| May 10, 2:31 PM CDT | Severe Thunderstorm Warning | OAX | Monona | 29 min |
| May 10, 2:51 PM CDT | Tornado Warning | FSD | Sioux | 24 min |
| May 10, 3:15 PM CDT | Severe Thunderstorm Warning | FSD | Plymouth | 30 min |
| May 10, 3:27 PM CDT | Severe Thunderstorm Warning | FSD | Lyon, Sioux | 33 min |
| May 10, 3:51 PM CDT | Severe Thunderstorm Warning | FSD | Lyon | 24 min |
| May 10, 4:34 PM CDT | Flash Flood Warning | FSD | Lyon | 4 hr |
| May 10, 4:56 PM CDT | Severe Thunderstorm Warning | FSD | Beadle, Sanborn | 34 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, 3.8 hours before the alert went out and 207 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
- 460 J/kg
- Mixed-layer CIN
- -103 J/kg
- Mixed-layer LCL
- 625 m above ground
- 0-6 km bulk shear
- 42 kt
- 0-1 km storm-relative helicity
- 158 m²/s²
- 0-3 km storm-relative helicity
- 186 m²/s²
- Significant tornado parameter
- 0.3
- Supercell composite
- 0.9
The text
As transmitted, in the capitals the NWS used until 2016.
739 WWUS20 KWNS 101545 SEL6 SPC WW 101545 IAZ000-MNZ000-NEZ000-SDZ000-110200- URGENT - IMMEDIATE BROADCAST REQUESTED TORNADO WATCH NUMBER 156 NWS STORM PREDICTION CENTER NORMAN OK 1045 AM CDT SUN MAY 10 2015 THE NWS STORM PREDICTION CENTER HAS ISSUED A * TORNADO WATCH FOR PORTIONS OF WESTERN IOWA SOUTHWEST MINNESOTA EASTERN NEBRASKA SOUTHEASTERN SOUTH DAKOTA * EFFECTIVE THIS SUNDAY MORNING AND EVENING FROM 1045 AM UNTIL 900 PM CDT. * PRIMARY THREATS INCLUDE... A FEW TORNADOES LIKELY SCATTERED LARGE HAIL EVENTS TO 1.5 INCHES IN DIAMETER LIKELY ISOLATED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE SUMMARY...SCATTERED SUPERCELLS AND SHORT LINES OF SUSTAINED STORMS WITH A THREAT FOR HAIL...LOCALLY DAMAGING WIND...AND A FEW TORNADOES EXPECTED OVER WATCH AREA THROUGH EARLY TONIGHT. THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 80 STATUTE MILES EAST AND WEST OF A LINE FROM 10 MILES NORTH NORTHWEST OF BROOKINGS SOUTH DAKOTA TO 5 MILES SOUTH SOUTHWEST OF OMAHA NEBRASKA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU6). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE WARNINGS. && OTHER WATCH INFORMATION...CONTINUE...WW 154...WW 155... AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450. MEAN STORM MOTION VECTOR 21040. ...CORFIDI
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 10, 10:24 AM CDT | Mesoscale Discussion | SPC | Audubon, Buena Vista, Calhoun, Carroll, Cherokee, Clay and 16 more | 3 hr |
| May 10, 11:52 AM CDT | Mesoscale Discussion | SPC | Adams, Decatur, Fremont, Page, Ringgold, Taylor | 2 hr |
| May 10, 1:47 PM CDT | Severe Thunderstorm Watch | SPC | Adams, Fremont, Mills, Montgomery, Page, Ringgold and 2 more | 8 hr |
| May 10, 2:43 PM CDT | Mesoscale Discussion | SPC | Adams, Audubon, Buena Vista, Cass, Cherokee, Crawford and 11 more | 92 min |
| May 10, 3:13 PM CDT | Mesoscale Discussion | SPC | Page | 92 min |
| May 10, 5:17 PM CDT | Mesoscale Discussion | SPC | Cedar, Clinton, Des Moines, Henry, Iowa, Jackson and 9 more | 88 min |
Nearby
Tornado Watches in Iowa, 2015Tornado Watches in Nebraska, 2015Tornado Watches in South Dakota, 2015Every tornado 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.