

000 

WWUS20 KWNS 100312

SEL8

SPC WW 100312

IAZ000-NEZ000-SDZ000-101000-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 578

NWS STORM PREDICTION CENTER NORMAN OK

1015 PM CDT THU AUG 9 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       WESTERN IOWA

       EASTERN NEBRASKA

       EXTREME SOUTHEAST SOUTH DAKOTA



EFFECTIVE THIS THURSDAY NIGHT AND FRIDAY MORNING FROM 1015 PM

UNTIL 500 AM CDT.



HAIL TO 1.5 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 70

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 15 MILES NORTH

NORTHWEST OF NORFOLK NEBRASKA TO 25 MILES SOUTH SOUTHEAST OF

DENISON IOWA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8).



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 576...WW 577...



DISCUSSION...BOW ECHO COMPLEX CONTINUES TO ORGANIZE OVER NORTHEAST

NEB.  THESE STORMS ARE EXPECTED TO TRACK EAST-SOUTHEASTWARD AT

AROUND 30 KNOTS TOWARD THE OMA AREA AND INTO WESTERN IA AFTER

MIDNIGHT.  VERY UNSTABLE AIR MASS AND FAVORABLE MID/UPPER FLOW WILL

SUPPORT A RISK OF DAMAGING WINDS FOR ANOTHER FEW HOURS.



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

TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM

MOTION VECTOR 28030.





...HART

