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466 

WWUS20 KWNS 301957

SEL5

SPC WW 301957

NEZ000-SDZ000-WYZ000-310300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 505

NWS STORM PREDICTION CENTER NORMAN OK

155 PM MDT FRI AUG 30 2013



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

  NORTHWEST NEBRASKA AND THE NEBRASKA PANHANDLE

  WESTERN SOUTH DAKOTA

  PARTS OF FAR EASTERN WYOMING



* EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 155 PM UNTIL

  900 PM MDT.



* PRIMARY THREATS INCLUDE...

  SEVERAL LARGE HAIL EVENTS WITH A FEW VERY LARGE HAIL EVENTS TO 2

    INCHES IN DIAMETER POSSIBLE

  SEVERAL DAMAGING WIND GUSTS TO 70 MPH POSSIBLE



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 90

STATUTE MILES EAST AND WEST OF A LINE FROM 45 MILES EAST

NORTHEAST OF BUFFALO SOUTH DAKOTA TO 10 MILES EAST OF SIDNEY

NEBRASKA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU5).



PRECAUTIONARY/PREPAREDNESS ACTIONS...



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...CONTINUE...WW 504...



DISCUSSION...AN ISOLATED THUNDERSTORM HAS DEVELOPED OVER THE BLACK

HILLS THIS AFTERNOON...AS MODERATE AIRMASS DESTABILIZATION

CONTINUES.  ADDITIONALLY...VISIBLE SATELLITE IMAGERY SHOWS AN

INCREASE IN THE LOW-LEVEL CU FIELD BOTH NORTH AND SOUTH OF THE BLACK

HILLS OVER THE PAST HALF HOUR -- AND THUS EXPECT AN INCREASE IN

STORM COVERAGE TO OCCUR IN THE NEXT 1-2 HOURS.  CONVECTION IS ALSO

INCREASING ACROSS FAR EASTERN PORTIONS OF WY -- AND WITH MODERATE

/25 TO 35 KT/ WESTERLY MID-LEVEL FLOW ATOP LOW-LEVEL SOUTHEASTERLIES

YIELDING SHEAR SUPPORTIVE OF ORGANIZED/SEVERE STORMS...THREAT FOR

LARGE HAIL AND LOCALLY DAMAGING WINDS IS EVIDENT OVER THE NEXT

SEVERAL 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 29025.





...GOSS

