

000 

WWUS20 KWNS 172153

SEL0

SPC WW 172153

NEZ000-SDZ000-180500-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 560

NWS STORM PREDICTION CENTER NORMAN OK

350 PM MDT TUE JUN 17 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       WESTERN AND NORTH-CENTRAL NEBRASKA

       SOUTH-CENTRAL SOUTH DAKOTA



EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 350 PM UNTIL

1100 PM MDT.



HAIL TO 3 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 80

MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 60

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 25 MILES NORTHWEST

OF SCOTTSBLUFF NEBRASKA TO 35 MILES SOUTHEAST OF ONEILL NEBRASKA.

 FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU0).



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 557...WW 558...WW 559...



DISCUSSION...CLUSTER OF INTENSE CONVECTION ALONG WEAK WARM FRONTAL

BOUNDARY MAY CONTINUE TO DEVELOP SOUTH ALONG STRONG INSTABILITY

GRADIENT SITUATED GENERALLY N-S ACROSS NORTH-CENTRAL NEB THIS

EVENING. COUPLED WITH INCREASING NW-FLOW ALOFT THIS

CONVECTION...CURRENTLY EXHIBITING SUPERCELLULAR CHARACTERISTICS WITH

THE THREAT FOR VERY LARGE HAIL... MAY EVOLVE INTO A SMALL MCS WITH

DAMAGING THREAT INCREASING ACROSS PARTS OF NEB THROUGH THE EVENING.

ADDITIONALLY...LATEST HIGH-RES MODELS DEPICT ANOTHER MCS POSSIBLY

DEVELOPING FROM HIGH-BASED STORMS INITIATING ERN WY/WRN NEB. THIS

ACTIVITY WOULD ALSO PRODUCE LARGE HAIL AND DAMAGING WINDS AS IT

BECOMES INCREASINGLY ORGANIZED WITHIN CORRIDOR OF STRONGER

INSTABILITY ACROSS NEB PNHDL LATER TONIGHT.



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

TO 3 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70

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

MOTION VECTOR 34025.





...CARBIN

