

000 

WWUS20 KWNS 042245

SEL3

SPC WW 042245

NEZ000-050400-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 563

NWS STORM PREDICTION CENTER NORMAN OK

545 PM CDT SAT AUG 4 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       CENTRAL NEBRASKA



EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 545 PM UNTIL

1100 PM CDT.



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 50

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 30 MILES SOUTH

SOUTHWEST OF NORTH PLATTE NEBRASKA TO 55 MILES EAST OF BURWELL

NEBRASKA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU3).



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 562...



DISCUSSION...INTENSE THUNDERSTORMS EXPECTED TO CONTINUE/DEVELOP

INVOF SURFACE COLD FRONT SAGGING SWD INTO CENTRAL NEB THIS EVENING.

AIR MASS IS VERY UNSTABLE AND MODERATELY SHEARED.  DESPITE WARM AIR

ALOFT...DEGREE OF INSTABILITY...LOW LEVEL CONVERGENCE AND SUFFICIENT

SHEAR FOR ROTATING UPDRAFTS ALL FAVOR THREATS OF LARGE HAIL/DAMAGING

WINDS WITH THE STRONGER STORMS.



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 600. MEAN STORM

MOTION VECTOR 33015.





...EVANS

