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000 

WWUS20 KWNS 162214

SEL1

SPC WW 162214

MTZ000-WYZ000-170700-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 401

NWS STORM PREDICTION CENTER NORMAN OK

410 PM MDT SAT JUN 16 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       EASTERN MONTANA

       NORTHEAST WYOMING



EFFECTIVE THIS SATURDAY AFTERNOON AND SUNDAY MORNING FROM 410 PM

UNTIL 100 AM MDT.



TORNADOES...HAIL TO 2.5 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 85 STATUTE

MILES EAST AND WEST OF A LINE FROM 25 MILES NORTH OF GLASGOW

MONTANA TO 65 MILES SOUTH SOUTHWEST OF MOORCROFT WYOMING.  FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU1).



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 400...



DISCUSSION...A STRONG MID LEVEL TROUGH AND ASSOCIATED SURFACE LOW

WILL MOVE EWD TO ERN MT BY TONIGHT...WITH CONVECTION LIKELY TO

INCREASE IN COVERAGE/INTENSITY WHILE SPREADING EWD FROM CENTRAL INTO

ERN MT LATE THIS EVENING INTO TONIGHT.  THE PRIMARY CONVECTIVE

CLUSTER WILL BE PRECEDED BY THE ISOLATED SUPERCELL MOVING ALONG THE

WARM FRONT IN NE MT...AND THE POTENTIAL FOR SUPERCELL DEVELOPMENT

NEAR AND IMMEDIATELY E OF THE BIGHORNS IN WY.  A GRADUAL INCREASE IN

LOW-LEVEL MOISTURE BENEATH STEEP MID LEVEL LAPSE RATES...AND STRONG

DEEP LAYER SHEAR...WILL SUPPORT SUPERCELLS CAPABLE OF PRODUCING

LARGE HAIL AND A FEW TORNADOES.  THE THREAT FOR DAMAGING WINDS MAY

INCREASE TONIGHT IN CONJUNCTION WITH STORM MERGERS AND THE

POSSIBILITY OF BOW ECHO FORMATION.



AVIATION...TORNADOES AND 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

500. MEAN STORM MOTION VECTOR 27025.





...THOMPSON

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