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886 

WWUS20 KWNS 302348

SEL6

SPC WW 302348

MNZ000-SDZ000-310700-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 636

NWS STORM PREDICTION CENTER NORMAN OK

645 PM CDT MON AUG 30 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       SOUTHWEST MINNESOTA

       EASTERN SOUTH DAKOTA



EFFECTIVE THIS MONDAY NIGHT AND TUESDAY MORNING FROM 645 PM UNTIL

200 AM CDT.



TORNADOES...HAIL TO 1.5 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 55 STATUTE

MILES EAST AND WEST OF A LINE FROM 55 MILES SOUTH OF MITCHELL

SOUTH DAKOTA TO 40 MILES NORTHEAST OF ORTONVILLE MINNESOTA.  FOR

A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU6).



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.



OTHER WATCH INFORMATION...CONTINUE...WW 633...WW 634...WW 635...



DISCUSSION...INTENSE TSTMS ARE EXPECTED TO CONTINUE TO MOVE/DEVELOP

NNEWD ACROSS AREA TONIGHT IN ADVANCE OF MIDLEVEL VORTICITY

MAXIMUM/JET STREAK LIFTING THROUGH CNTRL NEB.  AMBIENT INFLOW AIR

MASS REMAINS QUITE MOIST AND UNSTABLE WITH DEWPOINTS OF AROUND 70 F

AND MLCAPE OF 1000-1500 J/KG.  AND WHILE CONVECTIVE MODE WILL REMAIN

LARGELY LINEAR...THE PRESENCE OF A 50-60 KT SLY LLJ AND RESULTANT

300-400 M2/S2 EFFECTIVE SRH SUGGEST THE THREAT FOR EMBEDDED

SUPERCELL STRUCTURES WITH A RISK FOR A COUPLE TORNADOES.



AVIATION...TORNADOES AND 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

500. MEAN STORM MOTION VECTOR 22040.





...MEAD

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