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WWUS20 KWNS 301834

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SPC WW 301834

MNZ000-SDZ000-310200-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 704

NWS STORM PREDICTION CENTER NORMAN OK

130 PM CDT SAT JUL 30 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       CENTRAL AND SOUTHERN MINNESOTA

       EASTERN SOUTH DAKOTA



EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 130 PM UNTIL

900 PM CDT.



HAIL TO 2.5 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 55

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 40 MILES WEST

SOUTHWEST OF WATERTOWN SOUTH DAKOTA TO 20 MILES SOUTHEAST OF

MINNEAPOLIS MINNESOTA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE

THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU4).



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...CONTINUE...WW 703...



DISCUSSION...AN INCIPIENT SUPERCELL APPEARS TO BE EVOLVING NEAR VVV

WITH ADDITIONAL STORM DEVELOPMENT ANTICIPATED THIS AFTERNOON ALONG

OUTFLOW BOUNDARY EXTENDING FROM N OF ABR-N OF MSP.  MODIFICATION OF

12Z ABR/MPX SOUNDINGS FOR CURRENT SURFACE CONDITIONS INDICATES THAT

CAP IS NOW QUITE WEAK WITH MLCAPE UPWARDS OF 3000-4000 J/KG.  AREA

VADS AND WOOD LAKE MN PROFILER SHOW THAT LOW-LEVEL WIND FIELD IS

RATHER WEAK...BUT SUFFICIENT DEEP-LAYER SHEAR DOES EXIST TO SUPPORT

SUPERCELL STRUCTURES.  WHILE A TORNADO IS POSSIBLE...IT DOES APPEAR

THAT VERY LARGE HAIL AND DAMAGING WINDS WILL BE THE PRIMARY HAZARDS.

STORMS MAY TEND TO MERGE AND EVOLVE INTO AN MCS LATE THIS AFTERNOON

INTO EVENING WITH A CONTINUE THREAT FOR DAMAGING WINDS AND HAIL.



AVIATION...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 600. MEAN STORM

MOTION VECTOR 30015.





...MEAD

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