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066 

WWUS20 KWNS 042358

SEL5

SPC WW 042358

MTZ000-050700-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 355

NWS STORM PREDICTION CENTER NORMAN OK

550 PM MDT MON JUN 4 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       NORTH CENTRAL MONTANA



EFFECTIVE THIS MONDAY AFTERNOON AND TUESDAY MORNING FROM 550 PM

UNTIL 100 AM MDT.



TORNADOES...HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND

GUSTS TO 75 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE

AREAS.



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 110 STATUTE

MILES EAST AND WEST OF A LINE FROM 45 MILES NORTHWEST OF HAVRE

MONTANA TO 55 MILES SOUTH OF GREAT FALLS MONTANA.  FOR A COMPLETE

DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE

(WOUS64 KWNS WOU5).



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 352...WW 353...WW 354...



DISCUSSION...SUPERCELLS MENTIONED IN SVR WW 354 ARE EXPECTED TO

STRENGTHEN AND DEVELOP LWR BASES AS THEY ENCOUNTER INCREASINGLY

MOIST LOW LVL ESELY FLOW ACROSS N CNTRL MT.  GREAT FALLS MT VWP

SAMPLES THE 25 KT ELY CURRENT VERY WELL.  WITH THE LOW LVL ELY FLOW

LIKELY TO STRENGTHEN AS THE CA/ORE UPR TROUGH ASSUMES MORE OF A

NEGATIVE TILT/ACCELERATES NNEWD...AND AS TEMP-DEW POINT SPREADS

DECREASE LATER THIS EVE...ENVIRONMENT WILL BECOME MORE FAVORABLE FOR

LOW LVL MESOCYCLONES/POSSIBLE TORNADOES.  A CONDITIONAL RISK WILL

EXIST FOR ONE OR TWO STRONG TORNADOES.



AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL

SURFACE AND ALOFT TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE

WIND GUSTS TO 65 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO

500. MEAN STORM MOTION VECTOR 21035.





...CORFIDI

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