

666 

WWUS20 KWNS 100322

SEL6

SPC WW 100322

SDZ000-101000-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 366

NWS STORM PREDICTION CENTER NORMAN OK

925 PM MDT SAT JUN 9 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SOUTHWEST AND CENTRAL SOUTH DAKOTA



EFFECTIVE THIS SATURDAY NIGHT AND SUNDAY MORNING FROM 925 PM

UNTIL 400 AM MDT.



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 60

STATUTE MILES EAST AND WEST OF A LINE FROM 40 MILES NORTHWEST OF

ABERDEEN SOUTH DAKOTA TO 75 MILES SOUTH SOUTHWEST OF PHILIP SOUTH

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

WATCH OUTLINE UPDATE (WOUS64 KWNS WOU6).



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.



DISCUSSION...STORMS WILL CONTINUE TO INCREASE IN COVERAGE/INTENSITY

THE NEXT FEW HOURS AS A BAND OF LOW-MIDLEVEL FRONTOGENESIS INTERACTS

WITH THE RICHER MOISTURE/INSTABILITY ACROSS CENTRAL SD.  DEEP-LAYER

VERTICAL SHEAR WILL BE FAVORABLE FOR BOTH SUPERCELLS AND ORGANIZED

BOWING SEGMENTS...WITH AN ATTENDANT RISK FOR LARGE HAIL AND DAMAGING

WINDS THROUGH THE OVERNIGHT HOURS.



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 500. MEAN STORM

MOTION VECTOR 24030.





...THOMPSON

