

918 

WWUS20 KWNS 261752

SEL5

SPC WW 261752

IAZ000-MNZ000-SDZ000-270100-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 415

NWS STORM PREDICTION CENTER NORMAN OK

1250 PM CDT SAT JUN 26 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       NORTHWESTERN IOWA

       SOUTHWESTERN MINNESOTA

       SOUTHEASTERN SOUTH DAKOTA



EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 1250 PM UNTIL

800 PM CDT.



TORNADOES...HAIL TO 4 INCHES IN DIAMETER...THUNDERSTORM WIND

GUSTS TO 90 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE

AREAS.



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 70 STATUTE

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

MITCHELL SOUTH DAKOTA TO 45 MILES EAST SOUTHEAST OF MANKATO

MINNESOTA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU5).



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...ELEVATED SUPERCELL WAS LOCATED IN SERN SD EAST OF

HURON. THIS STORM IS EXPECTED TO CONTINUE TRACKING EWD ALONG E-W

ORIENTED WARM FRONT AND EVENTUALLY BECOME SURFACE BASED. ONCE THIS

STORM IS ABLE TO TAP INTO THE BOUNDARY LAYER...ENVIRONMENTAL

CONDITIONS WILL BE VERY FAVORABLE FOR THIS STORM TO PRODUCE VERY

LARGE HAIL ...DAMAGING WINDS AS WELL AS TORNADOES. LATER THIS

AFTERNOON...OTHER SUPERCELLS ARE EXPECTED TO DEVELOP NEAR THE WARM

FRONT AND EAST OF SURFACE LOW IN SERN SD...WITH VERY LARGE

HAIL...WIND DAMAGE AND A FEW TORNADOES ALSO LIKELY.



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

SURFACE AND ALOFT TO 4 INCHES. EXTREME TURBULENCE AND SURFACE

WIND GUSTS TO 80 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO

600. MEAN STORM MOTION VECTOR 28020.





...IMY

