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822 

WWUS20 KWNS 270054

SEL2

SPC WW 270054

NEZ000-270800-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 562

NWS STORM PREDICTION CENTER NORMAN OK

655 PM MDT SUN JUN 26 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHWEST NEBRASKA



EFFECTIVE THIS SUNDAY NIGHT AND MONDAY MORNING FROM 655 PM UNTIL

200 AM MDT.



HAIL TO 2.5 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 65

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 85 MILES WEST OF

MULLEN NEBRASKA TO 45 MILES EAST OF MULLEN NEBRASKA.  FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU2).



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...THIS SEVERE THUNDERSTORM WATCH REPLACES

SEVERE THUNDERSTORM WATCH NUMBER 557. WATCH NUMBER 557 WILL NOT

BE IN EFFECT AFTER 655 PM MDT. CONTINUE...WW 555...WW 556...WW

559...WW 560...WW 561...



DISCUSSION...SCATTERED SEVERE STORMS WILL CONTINUE TO DEVELOP AHEAD

OF A COLD FRONT IN NW NEB...AND IN ADVANCE OF A SHORTWAVE TROUGH

EJECTING EWD ACROSS WY.  THE STORMS WILL BE MAINTAINED ALONG THE

COOL SIDE OF AN OUTFLOW BOUNDARY FROM EARLIER STORMS IN CENTRAL

NEB...WHERE  THE 00Z LBF SOUNDING STILL SHOWS MODERATE INSTABILITY

JUST ABOVE THE SURFACE TO THE N OF THE OUTFLOW BOUNDARY.  DEEP-LAYER

VERTICAL SHEAR REMAINS FAVORABLE FOR SUPERCELLS...WITH LARGE HAIL

AND DAMAGING WINDS THE MAIN SEVERE THREATS.



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 500. MEAN STORM

MOTION VECTOR 29025.





...THOMPSON

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