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WWUS20 KWNS 062351

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URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 354

NWS STORM PREDICTION CENTER NORMAN OK

550 PM MDT WED JUN 6 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       EASTERN MONTANA

       SOUTHERN AND CENTRAL NORTH DAKOTA

       NORTHWEST SOUTH DAKOTA



EFFECTIVE THIS WEDNESDAY AFTERNOON AND THURSDAY MORNING FROM 550

PM UNTIL 100 AM MDT.



TORNADOES...HAIL TO 2 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 160 STATUTE

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

LEMMON SOUTH DAKOTA TO 30 MILES WEST NORTHWEST OF GARRISON NORTH

DAKOTA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED

WATCH OUTLINE UPDATE (WOUS64 KWNS WOU4).



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...THIS TORNADO WATCH REPLACES TORNADO

WATCH NUMBER 352. WATCH NUMBER 352 WILL NOT BE IN EFFECT AFTER

550 PM MDT. CONTINUE...WW 353...



DISCUSSION...EXISTING QUASI-LINEAR MCS OVER SE MT/WRN SD EXPECTED TO

CONTINUE GENERALLY NEWD THROUGH MID/LATE EVENING...WITH ADDITIONAL

STORMS POSSIBLY FORMING INVOF BACK-DOOR FRONT IN ERN MT...AND ALONG

INVERTED TROUGH IN CNTRL ND.  COMBINATION OF MOIST LOW LEVEL NE/E

FLOW...BACKED AT A CONSIDERABLE ANGLE TO MODERATE SLY MID/UPR LEVEL

WINDS...WILL MAINTAIN ENVIRONMENT SUPPORTIVE OF LOW LEVEL STORM

ROTATION DESPITE QUASI-LINEAR LARGER SCALE STORM MODE.  ACTIVITY

LIKELY WILL EVOLVE INTO ONE OR TWO LOOSELY ORGANIZED MCSS LATER THIS

EVENING...WITH MAIN SVR THREATS THEN BEING WIND/HAIL.



AVIATION...TORNADOES AND 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 24025.





...CORFIDI

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