

000 

WWUS20 KWNS 142057

SEL7

SPC WW 142057

NEZ000-150300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 597

NWS STORM PREDICTION CENTER NORMAN OK

400 PM CDT TUE AUG 14 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTH CENTRAL AND NORTHEAST NEBRASKA



EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 400 PM UNTIL

1000 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 65

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 75 MILES WEST OF

MULLEN NEBRASKA TO 65 MILES EAST SOUTHEAST OF ONEILL NEBRASKA.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU7).



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...WIDELY SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP

ALONG A BAROCLINIC ZONE ACROSS CENTRAL NEB WHERE THE LOW LEVELS HAVE

DESTABILIZED AND THE CAP IS GRADUALLY WEAKENING.  STRONG INSTABILITY

IS PRESENT ALONG AND N OF THE BOUNDARY...WHERE LOW-LEVEL ELY FLOW

BENEATH MODEST MID LEVEL WLY FLOW WILL PROMOTE STORMS WITH SOME

SUPERCELL STRUCTURE.  LARGE HAIL AND DAMAGING WINDS WILL BE THE MAIN

SEVERE THREATS.



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 29020.





...THOMPSON

