

647 

WWUS20 KWNS 252211

SEL8

SPC WW 252211

KSZ000-NEZ000-260400-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 218

NWS STORM PREDICTION CENTER NORMAN OK

510 PM CDT SAT MAY 25 2013



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

  WESTERN KANSAS

  EXTREME SOUTHWEST NEBRASKA



* EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 510 PM UNTIL

  1100 PM CDT.



* PRIMARY THREATS INCLUDE...

  A FEW DAMAGING WIND GUSTS TO 70 MPH POSSIBLE

  A FEW LARGE HAIL EVENTS TO 1.5 INCHES IN DIAMETER POSSIBLE



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 50

STATUTE MILES EAST AND WEST OF A LINE FROM 30 MILES WEST

NORTHWEST OF MCCOOK NEBRASKA TO 10 MILES WEST SOUTHWEST OF

LIBERAL KANSAS.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8).



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 217...



DISCUSSION...HIGH-BASED STORMS FORMING ALONG THE DRYLINE WILL SPREAD

SLOWLY EWD THROUGH THIS EVENING...WITH LARGE HAIL THE PRIMARY RISK

IN AN ENVIRONMENT OF MODERATE INSTABILITY/STEEP LAPSE RATES...AND

EFFECTIVE BULK SHEAR OF 25-30 KT.  LATER THIS EVENING...STORM

MERGERS COULD LEAD TO SOME UPSCALE GROWTH INTO ONE OR MORE

CLUSTERS...WITH AN ATTENDANT RISK FOR STRONG/DAMAGING OUTFLOW WINDS

BEFORE THE BOUNDARY LAYER STABILIZES TONIGHT.



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

TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

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

MOTION VECTOR 27020.





...THOMPSON

