Alert archive / Minnesota / Tornado Watches in 2009
Tornado Watch 677
The Storm Prediction Center issued this tornado watch at Aug 8, 2009, 12:47 PM CDT for Lyon County, Osceola County, Iowa; 29 counties in Minnesota; 20 counties in South Dakota. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 8, 2009, 12:47 PM CDT (17:47 UTC)
- Expired
- Aug 8, 2009, 5:56 PM CDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 3 in
- Strongest gust expected
- 70 kt
All 51 counties
Lyon County, IA, Osceola County, IA, Big Stone County, MN, Brown County, MN, Chippewa County, MN, Cottonwood County, MN, Douglas County, MN, Jackson County, MN, Kandiyohi County, MN, Lac qui Parle County, MN, Lincoln County, MN, Lyon County, MN, Martin County, MN, McLeod County, MN, Meeker County, MN, Murray County, MN, Nicollet County, MN, Nobles County, MN, Pipestone County, MN, Pope County, MN, Redwood County, MN, Renville County, MN, Rock County, MN, Sibley County, MN, Stearns County, MN, Stevens County, MN, Swift County, MN, Todd County, MN, Traverse County, MN, Watonwan County, MN, Yellow Medicine County, MN, Bon Homme County, SD, Brookings County, SD, Clay County, SD, Codington County, SD, Davison County, SD, Deuel County, SD, Grant County, SD, Hamlin County, SD, Hanson County, SD, Hutchinson County, SD, Kingsbury County, SD, Lake County, SD, Lincoln County, SD, McCook County, SD, Miner County, SD, Minnehaha County, SD, Moody County, SD, Turner County, SD, Union County, SD, Yankton County, SD
The radar
The Sioux Falls radar (KFSD), 110 km from the middle of the area, began a volume at 17:49 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
- 30%
- Ten or more severe wind reports
- 50%
- One or more gusts of 65 knots or more
- 50%
- Ten or more severe hail reports
- 80%
- One or more hailstones of 2 inches or more
- 60%
- Six or more combined severe hail and wind reports
- 95%
Warnings issued inside it
12 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 8, 1:12 PM CDT | Tornado Warning | FSD | Hanson, Hutchinson, McCook | 33 min |
| Aug 8, 1:15 PM CDT | Tornado Warning | FSD | Hanson, McCook, Miner | 30 min |
| Aug 8, 1:42 PM CDT | Tornado Warning | FSD | McCook, Minnehaha | 33 min |
| Aug 8, 1:55 PM CDT | Severe Thunderstorm Warning | FSD | Bon Homme, Charles Mix, Gregory, Hutchinson, Yankton | 50 min |
| Aug 8, 1:59 PM CDT | Tornado Warning | FSD | McCook, Minnehaha | 16 min |
| Aug 8, 2:12 PM CDT | Tornado Warning | FSD | Lake, McCook, Minnehaha, Moody | 33 min |
| Aug 8, 2:25 PM CDT | Severe Thunderstorm Warning | FSD | Pipestone | 35 min |
| Aug 8, 2:43 PM CDT | Severe Thunderstorm Warning | FSD | Bon Homme, Hutchinson, Turner, Yankton | 30 min |
| Aug 8, 2:47 PM CDT | Tornado Warning | FSD | Bon Homme, Yankton | 23 min |
| Aug 8, 3:15 PM CDT | Severe Thunderstorm Warning | FSD | Lincoln, Lyon, Murray, Pipestone | 30 min |
| Aug 8, 3:42 PM CDT | Severe Thunderstorm Warning | FSD | Lyon, Murray | 23 min |
| Aug 8, 3:46 PM CDT | Severe Thunderstorm Warning | MPX | Brown, Redwood | 28 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
Aberdeen, SD (KABR), launched 12:00Z, 5.8 hours before the alert went out and 168 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
- 3 J/kg
- Mixed-layer CIN
- -564 J/kg
- Mixed-layer LCL
- 1478 m above ground
- 0-6 km bulk shear
- 44 kt
- 0-1 km storm-relative helicity
- -219 m²/s²
- 0-3 km storm-relative helicity
- -319 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 7, 8:58 PM CDT | Mesoscale Discussion | SPC | Black Hawk, Boone, Bremer, Buchanan, Buena Vista, Butler and 35 more | 92 min |
| Aug 7, 10:14 PM CDT | Severe Thunderstorm Watch | SPC | Black Hawk, Boone, Bremer, Buena Vista, Butler, Calhoun and 27 more | 6 hr |
| Aug 8, 1:29 AM CDT | Mesoscale Discussion | SPC | Allamakee, Benton, Black Hawk, Boone, Bremer, Buchanan and 37 more | 2 hr |
| Aug 8, 12:16 PM CDT | Mesoscale Discussion | SPC | Dickinson, Emmet, Lyon, Osceola | 29 min |
| Aug 8, 3:27 PM CDT | Mesoscale Discussion | SPC | Dickinson, Lyon, Osceola | 33 min |
| Aug 8, 9:29 AM CDT | Mesoscale Discussion | SPC | Anoka, Brown, Carver, Dakota, Goodhue, Hennepin and 12 more | 91 min |
| Aug 8, 2:17 PM CDT | Mesoscale Discussion | SPC | Wilkin | 58 min |
| Aug 8, 3:46 PM CDT | Tornado Watch | SPC | Anoka, Benton, Blue Earth, Carver, Chisago, Dakota and 24 more | 8 hr |
| Aug 8, 5:36 PM CDT | Mesoscale Discussion | SPC | Anoka, Benton, Blue Earth, Brown, Carver, Chisago and 26 more | 84 min |
| Aug 7, 8:29 PM CDT | Mesoscale Discussion | SPC | Buffalo, Haakon, Hughes, Hyde, Jackson, Jones and 3 more | 91 min |
| Aug 7, 8:57 PM CDT | Severe Thunderstorm Watch | SPC | Brule, Buffalo, Charles Mix, Gregory, Hand, Hughes and 8 more | 5 hr |
| Aug 7, 9:53 PM CDT | Mesoscale Discussion | SPC | Butte, Harding, Lawrence, Meade, Pennington, Perkins | 97 min |
| Aug 7, 11:22 PM CDT | Mesoscale Discussion | SPC | Buffalo, Hughes, Hyde, Jones, Lyman, Mellette and 2 more | 83 min |
| Aug 8, 3:18 AM CDT | Mesoscale Discussion | SPC | Bennett, Butte, Custer, Fall River, Haakon, Jackson and 6 more | 117 min |
| Aug 8, 10:52 AM CDT | Mesoscale Discussion | SPC | Aurora, Beadle, Bennett, Brookings, Brown, Brule and 36 more | 23 min |
| Aug 8, 11:15 AM CDT | Severe Thunderstorm Watch | SPC | Aurora, Beadle, Bon Homme, Brookings, Brown, Brule and 31 more | 4 hr |
Nearby
Tornado Watches in Minnesota, 2009Tornado Watches in South Dakota, 2009Tornado Watches in Iowa, 2009Every tornado watch in 2009
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.