Alert archive / South Dakota / Tornado Watches in 2008
Tornado Watch 770
The Storm Prediction Center issued this tornado watch at Jul 28, 2008, 10:15 PM CDT for Big Stone County, Traverse County, Minnesota; 14 counties in South Dakota. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 28, 2008, 10:15 PM CDT (03:15 UTC)
- Expired
- Jul 29, 2008, 2:40 AM CDT
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2.5 in
- Strongest gust expected
- 60 kt
Counties Big Stone County, MN, Traverse County, MN, Brown County, SD, Clark County, SD, Codington County, SD, Day County, SD, Deuel County, SD, Edmunds County, SD, Faulk County, SD, Grant County, SD, Hamlin County, SD, Hand County, SD, Marshall County, SD, McPherson County, SD, Roberts County, SD, Spink County, SD
The radar
The Aberdeen radar (KABR), 21 km from the middle of the area, began a volume at 03:15 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
- 40%
- One or more EF2 to EF5 tornadoes
- 20%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 40%
- Ten or more severe hail reports
- 60%
- One or more hailstones of 2 inches or more
- 40%
- Six or more combined severe hail and wind reports
- 80%
Warnings issued inside it
5 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 28, 10:38 PM CDT | Severe Thunderstorm Warning | ABR | Brown | 67 min |
| Jul 28, 10:43 PM CDT | Severe Thunderstorm Warning | ABR | Brown, McPherson | 62 min |
| Jul 28, 11:31 PM CDT | Severe Thunderstorm Warning | ABR | Codington, Deuel, Grant | 33 min |
| Jul 28, 11:41 PM CDT | Severe Thunderstorm Warning | ABR | Brown, Day, Marshall | 52 min |
| Jul 29, 12:08 AM CDT | Severe Thunderstorm Warning | ABR | Brown, Clark, Day, Spink | 31 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 00:00Z, 3.3 hours before the alert went out and 44 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
- 4093 J/kg
- Mixed-layer CIN
- -2 J/kg
- Mixed-layer LCL
- 826 m above ground
- 0-6 km bulk shear
- 44 kt
- 0-1 km storm-relative helicity
- 100 m²/s²
- 0-3 km storm-relative helicity
- 360 m²/s²
- Significant tornado parameter
- 4.8
- Supercell composite
- 26.1
The text
As transmitted, in the capitals the NWS used until 2016.
000
WWUS20 KWNS 290314
SEL0
SPC WW 290314
MNZ000-SDZ000-290900-
URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 770
NWS STORM PREDICTION CENTER NORMAN OK
1010 PM CDT MON JUL 28 2008
THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF
WESTERN MINNESOTA
NORTHEASTERN SOUTH DAKOTA
EFFECTIVE THIS MONDAY NIGHT AND TUESDAY MORNING FROM 1010 PM
UNTIL 400 AM CDT.
TORNADOES...HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.
THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 55 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 60 MILES WEST SOUTHWEST OF
ABERDEEN SOUTH DAKOTA TO 40 MILES EAST NORTHEAST OF WATERTOWN
SOUTH DAKOTA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).
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 767...WW 768...WW 769...
DISCUSSION...STORMS ARE EXPECTED TO CONTINUE DEVELOPING WITHIN ZONE
OF LOW LEVEL WARM ADVECTION AND WITHIN AREA OF STRONG INSTABILITY
OVER NERN SD NEXT SEVERAL HOURS. STRONG INSTABILITY WITH MLCAPE TO
4000 J/KG AND BULK SHEAR AROUND 45 KT WILL SUPPORT ORGANIZED STORMS
INCLUDING SUPERCELLS WITH VERY LARGE HAIL AND DAMAGING WIND
POSSIBLE. THE 0-1 KM HODOGRAPHS SIZE WILL INCREASE AS THE LOW LEVEL
JET STRENGTHENS WITH A WINDOW OF OPPORTUNITY FOR ISOLATED TORNADOES
BEFORE THE BOUNDARY LAYER DECOUPLES.
AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
600. MEAN STORM MOTION VECTOR 32025.
...DIAL/HARTSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 28, 7:09 PM CDT | Mesoscale Discussion | SPC | Big Stone | 111 min |
| Jul 28, 7:09 PM CDT | Mesoscale Discussion | SPC | Big Stone | 2 hr |
| Jul 28, 9:55 PM CDT | Severe Thunderstorm Watch | SPC | Becker, Clay, Grant, Kittson, Mahnomen, Marshall and 6 more | 6 hr |
| Jul 29, 12:36 AM CDT | Mesoscale Discussion | SPC | Aitkin, Becker, Beltrami, Benton, Big Stone, Cass and 32 more | 84 min |
| Jul 29, 12:56 AM CDT | Severe Thunderstorm Watch | SPC | Aitkin, Beltrami, Benton, Cass, Chippewa, Clearwater and 24 more | 5 hr |
| Jul 29, 3:13 AM CDT | Severe Thunderstorm Watch | SPC | Carlton, Chisago, Isanti, Pine, Saint Louis | 3 hr |
| Jul 29, 2:51 PM CDT | Mesoscale Discussion | SPC | Winona | 84 min |
| Jul 28, 8:47 PM CDT | Mesoscale Discussion | SPC | Aurora, Beadle, Brule, Buffalo, Campbell, Charles Mix and 28 more | 88 min |
Nearby
Tornado Watches in South Dakota, 2008Tornado Watches in Minnesota, 2008Every tornado watch in 2008
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.