Alert archive / South Dakota / Severe Thunderstorm Watches in 2012
Severe Thunderstorm Watch 397
The Storm Prediction Center issued this severe thunderstorm watch at Jun 15, 2012, 5:14 PM CDT for 4 counties in Nebraska; 21 counties in South Dakota. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Jun 15, 2012, 5:14 PM CDT (22:14 UTC)
- Expired
- Jun 15, 2012, 11:21 PM CDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 25 counties
Brown County, NE, Cherry County, NE, Keya Paha County, NE, Sheridan County, NE, Bennett County, SD, Buffalo County, SD, Corson County, SD, Dewey County, SD, Edmunds County, SD, Faulk County, SD, Haakon County, SD, Hand County, SD, Hughes County, SD, Hyde County, SD, Jackson County, SD, Jones County, SD, Lyman County, SD, Mellette County, SD, Potter County, SD, Stanley County, SD, Sully County, SD, Todd County, SD, Tripp County, SD, Walworth County, SD, Ziebach County, SD
The radar
The Rapid City radar (KUDX), 147 km from the middle of the area, began a volume at 22:14 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
- 20%
- One or more EF2 to EF5 tornadoes
- 5%
- Ten or more severe wind reports
- 50%
- One or more gusts of 65 knots or more
- 40%
- Ten or more severe hail reports
- 40%
- One or more hailstones of 2 inches or more
- 30%
- Six or more combined severe hail and wind reports
- 80%
Warnings issued inside it
3 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 15, 5:18 PM CDT | Severe Thunderstorm Warning | UNR | Haakon, Meade, Pennington, Ziebach | 57 min |
| Jun 15, 6:09 PM CDT | Severe Thunderstorm Warning | UNR | Haakon | 40 min |
| Jun 15, 7:05 PM CDT | Severe Thunderstorm Warning | UNR | Ziebach | 23 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
Rapid City, SD (KUNR), launched 12:00Z, 10.2 hours before the alert went out and 152 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1967 m above ground
- 0-6 km bulk shear
- 37 kt
- 0-1 km storm-relative helicity
- 26 m²/s²
- 0-3 km storm-relative helicity
- 277 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
The text
As transmitted, in the capitals the NWS used until 2016.
154
WWUS20 KWNS 152216
SEL7
SPC WW 152216
NEZ000-SDZ000-160600-
URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 397
NWS STORM PREDICTION CENTER NORMAN OK
515 PM CDT FRI JUN 15 2012
THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
NORTHERN NEBRASKA
CENTRAL SOUTH DAKOTA
EFFECTIVE THIS FRIDAY AFTERNOON AND SATURDAY MORNING FROM 515 PM
UNTIL 100 AM CDT.
HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.
THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 55
STATUTE MILES EAST AND WEST OF A LINE FROM 25 MILES NORTH
NORTHWEST OF MOBRIDGE SOUTH DAKOTA TO 60 MILES SOUTH SOUTHWEST OF
VALENTINE NEBRASKA. FOR A COMPLETE DEPICTION OF THE WATCH SEE
THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU7).
REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR 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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.
OTHER WATCH INFORMATION...CONTINUE...WW 395...WW 396...
DISCUSSION...STORMS DEVELOPING WITHIN LEE-SIDE/THERMAL LOW AND
DEVELOPING WARN FRONT ACROSS SD SHOULD CONTINUE TO SPREAD EAST ALONG
THE NEB/SD BORDER AND ALSO INTO AREAS OF CENTRAL SD THROUGH THE
EVENING HOURS. REGION LIES WITHIN/BENEATH MID LEVEL JET STREAK THAT
IS PROVIDING DEEP SHEAR SUPPORTIVE OF STORM ORGANIZATION AND
PERSISTENCE. IN ADDITION TO LARGE HAIL WITH INITIAL CELLULAR
DEVELOPMENT...STORM MERGERS AND SOME UPSCALE GROWTH WITHIN THE
DEEP-LAYER WLY FLOW REGIME...AND INCREASE IN NOCTURNAL LLJ...COULD
CONTRIBUTE TO MCS DEVELOPMENT WITH AN INCREASING CHANCE FOR MORE
NUMEROUS SEVERE OR NEAR SEVERE WIND EVENTS WITH TIME.
AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450. MEAN STORM
MOTION VECTOR 27015.
...CARBINSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 15, 1:54 PM CDT | Mesoscale Discussion | SPC | Banner, Box Butte, Cheyenne, Dawes, Deuel, Kimball and 3 more | 96 min |
| Jun 15, 2:35 PM CDT | Severe Thunderstorm Watch | SPC | Banner, Box Butte, Cheyenne, Dawes, Kimball, Morrill and 2 more | 7 hr |
| Jun 15, 4:59 PM CDT | Mesoscale Discussion | SPC | Cherry, Sheridan | 91 min |
Nearby
Severe Thunderstorm Watches in South Dakota, 2012Severe Thunderstorm Watches in Nebraska, 2012Every severe thunderstorm watch in 2012
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.