Alert archive / North Dakota / Tornado Watches in 2011
Tornado Watch 493
The Storm Prediction Center issued this tornado watch at Jun 17, 2011, 5:34 PM CDT for Big Stone County, Traverse County, Wilkin County, Minnesota; 10 counties in North Dakota; 7 counties in South Dakota. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- Jun 17, 2011, 5:34 PM CDT (22:34 UTC)
- Expired
- Jun 17, 2011, 10:32 PM CDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
Counties Big Stone County, MN, Traverse County, MN, Wilkin County, MN, Barnes County, ND, Cass County, ND, Foster County, ND, Griggs County, ND, Ransom County, ND, Richland County, ND, Sargent County, ND, Steele County, ND, Stutsman County, ND, Traill County, ND, Codington County, SD, Day County, SD, Deuel County, SD, Grant County, SD, Hamlin County, SD, Marshall County, SD, Roberts County, SD
The radar
The Aberdeen radar (KABR), 91 km from the middle of the area, began a volume at 22:37 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
- 20%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 30%
- One or more hailstones of 2 inches or more
- 10%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
8 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 17, 5:49 PM CDT | Tornado Warning | FGF | Sargent | 41 min |
| Jun 17, 5:55 PM CDT | Tornado Warning | FGF | Ransom, Sargent | 50 min |
| Jun 17, 6:11 PM CDT | Severe Thunderstorm Warning | ABR | Marshall, Roberts | 49 min |
| Jun 17, 6:14 PM CDT | Tornado Warning | FGF | Barnes, Ransom | 34 min |
| Jun 17, 6:27 PM CDT | Tornado Warning | FGF | Sargent | 33 min |
| Jun 17, 6:28 PM CDT | Tornado Warning | ABR | Marshall, Roberts | 32 min |
| Jun 17, 6:56 PM CDT | Severe Thunderstorm Warning | ABR | Roberts | 49 min |
| Jun 17, 7:39 PM CDT | Severe Thunderstorm Warning | ABR | Big Stone, Traverse | 51 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, 10.6 hours before the alert went out and 132 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
- 35 J/kg
- Mixed-layer CIN
- -177 J/kg
- Mixed-layer LCL
- 665 m above ground
- 0-6 km bulk shear
- 35 kt
- 0-1 km storm-relative helicity
- 87 m²/s²
- 0-3 km storm-relative helicity
- 106 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
939
WWUS20 KWNS 172238
SEL3
SPC WW 172238
MNZ000-NDZ000-SDZ000-180600-
URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 493
NWS STORM PREDICTION CENTER NORMAN OK
535 PM CDT FRI JUN 17 2011
THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF
WESTERN MINNESOTA
EASTERN NORTH DAKOTA
NORTHEAST SOUTH DAKOTA
EFFECTIVE THIS FRIDAY AFTERNOON AND SATURDAY MORNING FROM 535 PM
UNTIL 100 AM CDT.
TORNADOES...HAIL TO 1.5 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 40 STATUTE
MILES EAST AND WEST OF A LINE FROM 25 MILES SOUTHEAST OF
WATERTOWN SOUTH DAKOTA TO 70 MILES NORTHWEST OF FARGO NORTH
DAKOTA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED
WATCH OUTLINE UPDATE (WOUS64 KWNS WOU3).
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 490...WW 491...WW 492...
DISCUSSION...TSTMS FORMING ALONG/JUST AHEAD OF WEAK COLD FRONT IN
ERN PORTIONS OF THE DAKOTAS EXPECTED TO CONTINUE MOVING NEWD AS
REGION COMES UNDER INCREASING ASCENT ASSOCIATED WITH SHORTWAVE
IMPULSE ROTATING NE INTO WRN ND. COMBINATION OF LOW LVL VEERING
WIND PROFILES /WITH MODERATE SHEAR MAGNITUDES/...RELATIVELY MOIST
LOW TO MID LVL ENVIRONMENT...AND THE PROSPECT FOR ADDITIONAL SFC
HEATING/SEMI DISCRETE STORM DEVELOPMENT SUGGEST THE POTENTIAL FOR
TORNADOES... IN ADDITION TO HAIL AND PERHAPS LOCALLY DMG WIND.
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
500. MEAN STORM MOTION VECTOR 22025.
...CORFIDISPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 17, 4:51 PM CDT | Mesoscale Discussion | SPC | Big Stone, Chippewa, Clay, Grant, Lac qui Parle, Pope and 4 more | 84 min |
| Jun 17, 6:44 PM CDT | Mesoscale Discussion | SPC | Jackson, Nobles, Rock | 91 min |
| Jun 16, 8:26 PM CDT | Mesoscale Discussion | SPC | Charles Mix, Gregory, Lyman, Mellette, Todd, Tripp | 64 min |
Nearby
Tornado Watches in North Dakota, 2011Tornado Watches in South Dakota, 2011Tornado Watches in Minnesota, 2011Every tornado watch in 2011
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.