Tornado Watch 435

Issued

Jun 16, 2009, 4:16 PM CDT (21:16 UTC)

Expired

Jun 16, 2009, 11:00 PM CDT

In force

7 hr

Issued by

the Storm Prediction Center

Largest hail expected

2 in

Strongest gust expected

60 kt

Counties Aurora County, SD, Beadle County, SD, Bon Homme County, SD, Brule County, SD, Charles Mix County, SD, Clay County, SD, Davison County, SD, Douglas County, SD, Gregory County, SD, Hanson County, SD, Hutchinson County, SD, Jerauld County, SD, Kingsbury County, SD, McCook County, SD, Miner County, SD, Sanborn County, SD, Turner County, SD, Union County, SD, Yankton County, SD

The Sioux Falls radar (KFSD), 147 km from the middle of the area, began a volume at 21:17 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.

Two or more tornadoes

60%

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

30%

Six or more combined severe hail and wind reports

70%

• Mesoscale Discussion 1164Jun 16, 5:39 PM CDT
• Mesoscale Discussion 1167Jun 16, 8:47 PM CDT

031 
WWUS20 KWNS 162117
SEL5  
SPC WW 162117
SDZ000-170200-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 435
NWS STORM PREDICTION CENTER NORMAN OK
420 PM CDT TUE JUN 16 2009

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF 

       SOUTHEAST SOUTH DAKOTA

EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 420 PM UNTIL
900 PM CDT.

TORNADOES...HAIL TO 2 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 EAST AND WEST OF A LINE FROM 20 MILES NORTH NORTHWEST OF
HURON SOUTH DAKOTA TO 50 MILES SOUTH OF MITCHELL SOUTH DAKOTA. 
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU5).

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 433...WW 434...

DISCUSSION...SUPERCELLS WILL CONTINUE TO MOVE/DEVELOP SSEWD ALONG A
STALLED BAROCLINIC ZONE ACROSS SE SD...ALONG THE SERN PERIPHERY OF A
MID LEVEL LOW NEAR THE ND/SD BORDER.  DEEP LAYER AND LOW-LEVEL SHEAR
ARE SUFFICIENT FOR SUPERCELLS ALONG THE INSTABILITY AXIS NEAR AND E
OF THE BOUNDARY...WHILE LOW-LEVEL VERTICAL VORTICITY IS ALSO
MAXIMIZED ALONG THE WIND SHIFT.  A FEW TORNADOES...LARGE HAIL...AND
ISOLATED DOWNBURST WINDS WILL BE POSSIBLE FOR THE NEXT FEW HOURS.

AVIATION...TORNADOES AND 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
500. MEAN STORM MOTION VECTOR 32015.


...THOMPSON

Tornado Watches in South Dakota, 2009Every tornado watch in 2009

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.