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URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 662

NWS STORM PREDICTION CENTER NORMAN OK

955 PM CDT TUE SEP 14 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       CENTRAL AND EASTERN SOUTH DAKOTA



EFFECTIVE THIS TUESDAY NIGHT AND WEDNESDAY MORNING FROM 955 PM

UNTIL 500 AM CDT.



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 95

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 30 MILES NORTHWEST

OF PHILIP SOUTH DAKOTA TO 35 MILES EAST NORTHEAST OF HURON SOUTH

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

WATCH OUTLINE UPDATE (WOUS64 KWNS WOU2).



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.



OTHER WATCH INFORMATION...THIS SEVERE THUNDERSTORM WATCH REPLACES

TORNADO WATCH NUMBER 660. WATCH NUMBER 660 WILL NOT BE IN EFFECT

AFTER 955 PM CDT. CONTINUE...WW 661...



DISCUSSION...SLIGHTLY ELEVATED TSTMS/POSSIBLE SUPERCELLS EXPECTED TO

INCREASE IN COVERAGE AND STRENGTH THROUGH EARLY WED AS SLY LLJ/WAA

INCREASE AHEAD OF WY/CO UPR IMPULSE.  MODERATELY STRONG

UNIDIRECTIONAL CLOUD LAYER SHEAR AND DEEP EML SUGGEST POTENTIAL FOR

SVR HAIL AND POSSIBLY LOCALLY DMGG WIND...ESPECIALLY DURING EARLY

STAGES OF STORM DEVELOPMENT.



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 27030.





...CORFIDI

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