

572 

WWUS20 KWNS 061923

SEL4

SPC WW 061923

SDZ000-070200-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 444

NWS STORM PREDICTION CENTER NORMAN OK

225 PM CDT TUE JUL 6 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       A LARGE PART OF SOUTH CENTRAL AND SOUTHEAST SOUTH DAKOTA



EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 225 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 80 STATUTE

MILES EAST AND WEST OF A LINE FROM 55 MILES SOUTH OF CHAMBERLAIN

SOUTH DAKOTA TO 20 MILES NORTHWEST OF HURON 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.



DISCUSSION...A RATHER FOCUSED AREA OF CONCERN FOR SUPERCELL

DEVELOPMENT IS ACROSS SCENTRAL SD WHERE BOTH SHEAR AND INSTABILITY

ARE MAXIMIZED.  THUNDERSTORMS EXPECTED TO FORM QUICKLY WRN PORTION

OF WATCH AREA WHERE SURFACE CONVERGENCE IS GREATEST AND QUICKLY

BECOME SEVERE.  STORMS WILL LIKELY BECOME SUPERCELLS WITH POTENTIAL

FOR LARGE HAIL AND AT LEAST AN ISOLATED TORNADO AS THEY MOVE EWD

ACROSS THE WATCH AREA.



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

550. MEAN STORM MOTION VECTOR 26025.





...HALES

