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721 

WWUS20 KWNS 252101

SEL2

SPC WW 252101

SDZ000-260400-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 452

NWS STORM PREDICTION CENTER NORMAN OK

400 PM CDT SAT JUL 25 2015



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* TORNADO WATCH FOR PORTIONS OF

  CENTRAL AND NORTHERN SOUTH DAKOTA



* EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 400 PM UNTIL

  1100 PM CDT.



* PRIMARY THREATS INCLUDE...

  A COUPLE TORNADOES POSSIBLE

  SCATTERED LARGE HAIL AND ISOLATED VERY LARGE HAIL EVENTS TO 3

    INCHES IN DIAMETER POSSIBLE

  ISOLATED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE



SUMMARY...EXPECT DISCRETE STORMS/SUPERCELLS TO CONTINUE TO DEVELOP

ACROSS THE WATCH AREA THROUGH THE EVENING. ACTIVITY WILL BE

SUPPORTED BY STRONG TO LOCALLY EXTREME INSTABILITY AND THE PRESENCE

OF WEAK BACKGROUND ASCENT FOCUSED ALONG THERMAL TROUGH AND WEAK

SURFACE LOW SITUATED ACROSS CENTRAL SD. MAGNITUDE OF INSTABILITY AND

DEEP SHEAR WILL BE MORE THAN ADEQUATE FOR SUPERCELLS. TORNADO THREAT

MAY EVOLVE FROM DISCRETE CELLS NEAR A NARROW AXIS OF BACKED

LOW-LEVEL FLOW LEFT IN THE WAKE OF STORM COMPLEX EARLIER IN THE DAY.

LOWER LFC NEAR THIS WEAK BOUNDARY WILL ALSO SUPPORT THE CHANCE FOR

STRONGER MID TO LOW LEVEL ROTATION TO REACH THE SURFACE.



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 70 STATUTE

MILES NORTH AND SOUTH OF A LINE FROM 50 MILES NORTHWEST OF PIERRE

SOUTH DAKOTA TO 40 MILES NORTH NORTHEAST OF HURON SOUTH DAKOTA.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU2).



PRECAUTIONARY/PREPAREDNESS ACTIONS...



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 451...



AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL

SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE

WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO

500. MEAN STORM MOTION VECTOR 26020.





...CARBIN

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