

000 

WWUS20 KWNS 110556

SEL7

SPC WW 110556

MNZ000-SDZ000-111300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 507

NWS STORM PREDICTION CENTER NORMAN OK

1255 AM CDT WED JUN 11 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       EXTREME WEST CENTRAL MINNESOTA

       CENTRAL AND NORTHEAST SOUTH DAKOTA



EFFECTIVE THIS WEDNESDAY MORNING FROM 1255 AM UNTIL 800 AM CDT.



HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70

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 75 MILES NORTH

NORTHWEST OF PHILIP SOUTH DAKOTA TO 35 MILES NORTH NORTHEAST OF

BROOKINGS SOUTH DAKOTA.  FOR A COMPLETE DEPICTION OF THE WATCH

SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU7).



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...THIS SEVERE THUNDERSTORM WATCH REPLACES

TORNADO WATCH NUMBER 506. WATCH NUMBER 506 WILL NOT BE IN EFFECT

AFTER 1255 AM CDT.



DISCUSSION...ELEVATED THUNDERSTORMS WILL LIKELY PERSIST THROUGH THE

NIGHT AND DEVELOP BOTH EWD AND SEWD AS LOW-LEVEL MOISTENING AND WAA

OCCURS ON THE NOSE OF A 60-70 KT LLJ ACROSS THE CENTRAL PLAINS.

ELEVATED CAPE ON THE ORDER OF 2000 J/KG AND STRONG VERTICAL SHEAR

WILL SUPPORT BOTH SUPERCELL AND BOW STRUCTURES CAPABLE OF PRODUCING

LARGE HAIL.  ADDITIONALLY...DESPITE THE STABLE NEAR-SURFACE

LAYER...STRONG DOWNDRAFTS OF MID LEVEL ORIGIN COULD REACH THE

SURFACE WITH AN ACCOMPANYING THREAT FOR DAMAGING WINDS.



AVIATION...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 27025.





...THOMPSON

