

000 

WWUS20 KWNS 051556

SEL3

SPC WW 051556

IAZ000-MNZ000-NEZ000-SDZ000-060000-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 233

NWS STORM PREDICTION CENTER NORMAN OK

1055 AM CDT SAT MAY 5 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       NORTHWEST IOWA

       SOUTHWEST CORNER OF MINNESOTA

       PARTS OF NORTHEAST NEBRASKA

       PARTS OF SOUTHEAST AND SOUTH CENTRAL SOUTH DAKOTA



EFFECTIVE THIS SATURDAY MORNING AND EVENING FROM 1055 AM UNTIL

700 PM CDT.



TORNADOES...HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND

GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE

AREAS.



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 60 STATUTE

MILES NORTH AND SOUTH OF A LINE FROM 45 MILES NORTH NORTHWEST OF

AINSWORTH NEBRASKA TO 55 MILES NORTH OF DENISON IOWA.  FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU3).



REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR

TORNADOES AND 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.



OTHER WATCH INFORMATION...CONTINUE...WW 232...



DISCUSSION...THUNDERSTORMS DEVELOPING ON WARM FRONT LIFTING NWD

THROUGH THE WATCH THIS AFTERNOON.  VERY STRONG DEEP LAYER SHEAR

COUPLED WITH INCREASING INSTABILITY SUPPORTS STORMS BECOMING MORE

SURFACE BASED THIS AFTERNOON.  SUPERCELLS WILL CONTINUE TO DEVELOP

AND WITH SHEAR AND CAPE AVAILABLE LARGE HAIL WILL BE COMMON WITH

INCREASING THREAT OF TORNADOES DURING THE AFTERNOON.



AVIATION...TORNADOES AND 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

550. MEAN STORM MOTION VECTOR 23035.





...HALES

