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419 

WWUS20 KWNS 142233

SEL4

SPC WW 142233

NDZ000-SDZ000-150600-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 644

NWS STORM PREDICTION CENTER NORMAN OK

435 PM MDT THU JUL 14 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       SOUTHERN NORTH DAKOTA

       NORTHERN SOUTH DAKOTA



EFFECTIVE THIS THURSDAY AFTERNOON FROM 435 PM UNTIL MIDNIGHT MDT.



TORNADOES...HAIL TO 3 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 70 STATUTE

MILES NORTH AND SOUTH OF A LINE FROM 40 MILES NORTHWEST OF

BUFFALO SOUTH DAKOTA TO 85 MILES EAST NORTHEAST OF MOBRIDGE SOUTH

DAKOTA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED

WATCH OUTLINE UPDATE (WOUS64 KWNS WOU4).



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 642...WW 643...



DISCUSSION...THUNDERSTORMS ARE EXPECTED TO RAPIDLY DEVELOP OVER

NORTHWEST ND/SOUTHWEST SD AND TRACK EASTWARD ALONG A WARM FRONT

ACROSS THE WATCH AREA THIS EVENING.  VERY HIGH CAPE AND AMPLE LOW

LEVEL MOISTURE...COUPLED WITH VEERING LOW LEVEL AND MODERATELY

STRONG MID LEVEL WINDS...WILL PROMOTE A RISK OF SPLITTING SUPERCELLS

CAPABLE OF VERY LARGE HAIL AND ISOLATED TORNADOES.



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

550. MEAN STORM MOTION VECTOR 28030.





...HART

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