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WWUS20 KWNS 132223

SEL4

SPC WW 132223

COZ000-KSZ000-NEZ000-SDZ000-140500-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 474

NWS STORM PREDICTION CENTER NORMAN OK

425 PM MDT MON JUN 13 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHEAST COLORADO

       NORTHWEST KANSAS

       WESTERN NEBRASKA

       SOUTHWEST SOUTH DAKOTA `



EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 425 PM UNTIL

1100 PM MDT.



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 60

STATUTE MILES EAST AND WEST OF A LINE FROM 110 MILES NORTH

NORTHEAST OF ALLIANCE NEBRASKA TO 35 MILES SOUTHEAST OF LIMON

COLORADO.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU4).



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 473...



DISCUSSION...SCATTERED THUNDERSTORMS ARE FORMING OVER SOUTHEAST WY

AND EASTERN CO.  THESE STORMS ARE EXPECTED TO SPREAD EASTWARD ACROSS

THE WATCH AREA THROUGH THE EVENING...WHILE OTHER STORMS FORM IN THE

MOIST/UNSTABLE AIR MASS OVER WESTERN NEB.  DEEP LAYER EFFECTIVE

SHEAR IS STRONG...SUGGESTIVE OF A RISK OF SUPERCELLS CAPABLE OF

LARGE HAIL AND DAMAGING WINDS.



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.





...HART

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