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759 

WWUS20 KWNS 312024

SEL9

SPC WW 312024

MTZ000-WYZ000-010300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 199

NWS STORM PREDICTION CENTER NORMAN OK

220 PM MDT SAT MAY 31 2014



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

  EASTERN MONTANA

  A SMALL PART OF NORTH CENTRAL WYOMING



* EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 220 PM UNTIL

  900 PM MDT.



* PRIMARY THREATS INCLUDE...

  SCATTERED LARGE HAIL AND ISOLATED VERY LARGE HAIL EVENTS TO 2

    INCHES IN DIAMETER POSSIBLE

  SCATTERED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE

  A TORNADO OR TWO POSSIBLE



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 90

STATUTE MILES EAST AND WEST OF A LINE FROM 50 MILES NORTH

NORTHEAST OF GLASGOW MONTANA TO 70 MILES WEST SOUTHWEST OF

BROADUS MONTANA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU9).



PRECAUTIONARY/PREPAREDNESS ACTIONS...



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.



&&



DISCUSSION...STORMS ARE INCREASING AHEAD OF A CONVECTIVELY-INDUCED

CYCLONIC CIRCULATION OVER ERN MT.  THE AIR MASS IS MOIST AND

MODERATELY UNSTABLE IN ADVANCE OF THE CONVECTION WITH SURFACE DEW

POINTS IN THE MID/UPPER 50S AND MLCAPE AROUND 1500 J/KG.  SELY LOW

LEVEL WINDS VEER WITH HEIGHT...AND ALTHOUGH SPEEDS ARE MODEST AT

THIS TIME...SOME STRENGTHENING OF THE FLOW AND ATTENDANT VERTICAL

SHEAR IS EXPECTED TO OCCUR LATER THIS AFTERNOON AND EVENING

PROMOTING SEVERE STORM DEVELOPMENT.  OTHER STRONG-SEVERE STORMS ARE

EXPECTED TO SPREAD NEWD FROM NWRN WY THROUGH THE EVENING HOURS.



AVIATION...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 23025.





...WEISS

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