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000 

WWUS20 KWNS 052133

SEL6

SPC WW 052133

IAZ000-MNZ000-NEZ000-SDZ000-060400-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 236

NWS STORM PREDICTION CENTER NORMAN OK

435 PM CDT SAT MAY 5 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       SMALL PART OF NORTHWEST IOWA

       SMALL PART OF SOUTHWEST MINNESOTA

       PARTS OF NORTHERN NEBRASKA

       MUCH OF CENTRAL AND EASTERN SOUTH DAKOTA



EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 435 PM UNTIL

1100 PM CDT.



...THIS IS A PARTICULARLY DANGEROUS SITUATION...



DESTRUCTIVE TORNADOES...LARGE HAIL TO 2.5 INCHES IN DIAMETER...

THUNDERSTORM WIND GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE

POSSIBLE IN THESE AREAS.



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 130 STATUTE

MILES NORTH AND SOUTH OF A LINE FROM 5 MILES SOUTH OF PHILIP

SOUTH DAKOTA TO 50 MILES EAST NORTHEAST OF SIOUX FALLS SOUTH

DAKOTA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED

WATCH OUTLINE UPDATE (WOUS64 KWNS WOU6).



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...THIS TORNADO WATCH REPLACES TORNADO

WATCH NUMBER 233. WATCH NUMBER 233 WILL NOT BE IN EFFECT AFTER

435 PM CDT. CONTINUE...WW 232...WW 234...WW 235...



DISCUSSION...WARM FRONT CONTINUES NWD THRU SD WITH A VERY STRONG AND

INCREASINGLY UNSTABLE AIRMASS SHIFTING NWD AS WELL.  TORNADIC

SUPERCELLS EXPECTED TO DEVELOP NWD ACROSS THE WATCH WITH POTENTIAL

FOR STRONG TORNADOES GIVEN THE SHEAR/INSTABILITY IN PLACE.



AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL

SURFACE AND ALOFT TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE

WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO

550. MEAN STORM MOTION VECTOR 21035.





...HALES

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