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WWUS20 KWNS 212331

SEL0

SPC WW 212331

NEZ000-SDZ000-220600-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 340

NWS STORM PREDICTION CENTER NORMAN OK

630 PM CDT FRI JUN 21 2013



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

  WEST CENTRAL NEBRASKA

  SOUTHERN SOUTH DAKOTA



* EFFECTIVE THIS FRIDAY NIGHT AND SATURDAY MORNING FROM 630 PM

  UNTIL 100 AM CDT.



* PRIMARY THREATS INCLUDE...

  SEVERAL DAMAGING WIND GUSTS WITH A FEW SIGNIFICANT GUSTS TO 75

    MPH POSSIBLE

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

    INCHES IN DIAMETER POSSIBLE



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 50

STATUTE MILES EAST AND WEST OF A LINE FROM 65 MILES NORTH

NORTHWEST OF VALENTINE NEBRASKA TO 35 MILES SOUTHWEST OF NORTH

PLATTE NEBRASKA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).



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 336...WW 337...WW

338...WW 339...



DISCUSSION...SEVERAL CLUSTERS OF SEVERE STORMS ARE ONGOING FROM NW

NEB EXTENDING SWD TO NEAR THE CO-NEB STATE-LINE. THIS ACTIVITY WILL

LIKELY PERSIST AND MAINTAIN A SEVERE THREAT THROUGH THIS EVENING. A

MODERATELY UNSTABLE AIRMASS ALONG WITH 45 TO 55 KT OF DEEP LAYER

SHEAR AND STEEP MID-LEVEL LAPSE RATES WILL MAKE WIND DAMAGE AND

LARGE HAIL POSSIBLE WITH THE STRONGER UPDRAFTS.



AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 65

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM

MOTION VECTOR 21030.





...BROYLES

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