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WWUS20 KWNS 050446

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URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 599

NWS STORM PREDICTION CENTER NORMAN OK

1140 PM CDT MON JUL 4 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR



       A SMALL PART OF WEST CENTRAL MINNESOTA

       PARTS OF CENTRAL AND EASTERN SOUTH DAKOTA



EFFECTIVE THIS MONDAY NIGHT AND TUESDAY MORNING FROM 1140 PM

UNTIL 600 AM CDT.



HAIL TO 1.5 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 85

STATUTE MILES EAST AND WEST OF A LINE FROM 60 MILES SOUTH

SOUTHEAST OF CHAMBERLAIN SOUTH DAKOTA TO 35 MILES NORTH NORTHEAST

OF ABERDEEN SOUTH DAKOTA.  FOR A COMPLETE DEPICTION OF THE WATCH

SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU9).



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 597...WW 598...



DISCUSSION...RESERVOIR OF STRONG INSTABILITY OVER CNTRL AND ERN SD

/PER 00Z ABR RAOB/ EXPECTED TO LARGELY BE OVERTURNED LATER

TNGT/EARLY TUE AS LOW LVL UPLIFT CONTINUES BOTH ALONG SEWD MOVING

COLD FRONT IN NRN PART OF WW...AND ALONG OUTFLOW

BOUNDARIES/CONFLUENCE AXES IN WRN PART OF WW.  AREA IS ON NW FRINGE

OF UPR RIDGE AND WILL BE GLANCED BY A UPR IMPULSE NOW IN WY.  LARGE

SCALE ASCENT ALSO WILL BE PROVIDED BY MODERATE LOW LVL WAA.  THESE

FORCES SHOULD OFFSET DIURNALLY INCREASING CINH TO SUPPORT SOME

THREAT FOR DMGG WIND AND HAIL AS THE STORMS FURTHER EVOLVE INTO ONE

OR MORE SE- TO SSE-MOVING COMPLEXES TUE MORNING.



AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM

MOTION VECTOR 30020.





...CORFIDI

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