

000 

WWUS20 KWNS 012135

SEL3

SPC WW 012135

IAZ000-MNZ000-SDZ000-020400-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 243

NWS STORM PREDICTION CENTER NORMAN OK

435 PM CDT THU MAY 1 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       PARTS OF NORTHWEST IOWA

       PARTS OF SOUTHWESTERN MINNESOTA

       LARGE PART OF SOUTHEASTERN SOUTH DAKOTA



EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 435 PM UNTIL

1100 PM CDT.



TORNADOES...HAIL TO 2 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 WEST SOUTHWEST OF

HURON SOUTH DAKOTA TO 35 MILES EAST SOUTHEAST OF SPENCER 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.



DISCUSSION...STRONG SELY FLOW E OF DEEP SFC LOW JUST S OF

YKN...RESULTING IN AN INCREASINGLY MOIST/UNSTABLE AIR MASS MOVING

NWWD THRU WATCH AREA.  THUNDERSTORMS WILL DEVELOP VICINITY COLD

FRONT THAT IS MOVING EWD THRU ERN NEB AND MOVE NWD THRU THE WATCH

AREA.  STRONG VEERING SHEAR PROFILES SUPPORT SUPERCELLS INCLUDING

TORNADOES AND LARGE HAIL.



AVIATION...TORNADOES AND 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 19025.





...HALES

