

495 

WWUS20 KWNS 301930

SEL2

SPC WW 301930

NEZ000-SDZ000-310400-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 452

NWS STORM PREDICTION CENTER NORMAN OK

130 PM MDT TUE JUL 30 2013



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

  NORTH-CENTRAL AND WESTERN NEBRASKA

  WESTERN AND CENTRAL SOUTH DAKOTA



* EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 130 PM UNTIL

  1000 PM MDT.



* PRIMARY THREATS INCLUDE...

  SEVERAL VERY LARGE HAIL EVENTS TO 2.5 INCHES IN DIAMETER

    POSSIBLE

  SEVERAL DAMAGING WIND GUSTS TO 70 MPH POSSIBLE

  A FEW TORNADOES POSSIBLE



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 85

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

NORTHEAST OF BUFFALO SOUTH DAKOTA TO 35 MILES SOUTHEAST OF MULLEN

NEBRASKA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU2).



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.



&&



DISCUSSION...TSTMS ARE EXPECTED TO INCREASE IN COVERAGE AND

INTENSITY THIS AFTERNOON FROM THE VICINITY OF A COLD FRONT OVER NWRN

SD SWD ALONG A LEE TROUGH INTO WRN AND N-CNTRL PARTS OF NEB.

HERE...A MODERATELY UNSTABLE AIR MASS COINCIDES WITH A KINEMATIC

ENVIRONMENT FEATURING A VERTICALLY VEERING WIND PROFILE WITH

DEEP-LAYER SHEAR RANGING FROM 45-55 KT ACROSS SD TO 30-35 KT ACROSS

NEB.  AS SUCH...THE POTENTIAL WILL EXIST FOR SUPERCELLS CAPABLE OF

VERY LARGE HAIL AND PERHAPS A TORNADO OR TWO /NAMELY OVER WRN SD/.

STORMS MAY COALESCE INTO SEWD-MOVING CLUSTERS BY THIS EVENING WITH A

CONTINUED RISK FOR LARGE HAIL AND DAMAGING WINDS.



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

TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM

MOTION VECTOR 30020.





...MEAD

