

493 

WWUS20 KWNS 182037

SEL6

SPC WW 182037

MTZ000-190400-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 326

NWS STORM PREDICTION CENTER NORMAN OK

240 PM MDT TUE JUN 18 2013



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

  WEST CENTRAL AND NORTHWEST MONTANA



* EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 240 PM UNTIL

  1000 PM MDT.



* PRIMARY THREATS INCLUDE...

  SEVERAL DAMAGING WIND GUSTS TO 70 MPH POSSIBLE

  SEVERAL LARGE HAIL EVENTS TO 1.5 INCHES IN DIAMETER POSSIBLE



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 90

STATUTE MILES EAST AND WEST OF A LINE FROM 25 MILES NORTH OF CUT

BANK MONTANA TO 30 MILES SOUTH SOUTHWEST OF HELENA MONTANA.  FOR

A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU6).



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.



&&



OTHER WATCH INFORMATION...CONTINUE...WW 324...WW 325...



DISCUSSION...THUNDERSTORMS DEVELOPING OVER THE MOUNTAINS OF SW MT

WILL SPREAD NWD/NEWD THROUGH THE EVENING...WITH STRENGTHENING OF THE

STORMS EXPECTED AS THE STORMS ENCOUNTER STRONGER INSTABILITY AWAY

FROM THE MOUNTAINS.  A FEW ORGANIZED STORM CLUSTERS ARE

EXPECTED...ALONG WITH A COUPLE OF MORE DISCRETE SUPERCELLS...WITH

THE RISK FOR LARGE HAIL AND DAMAGING WINDS THROUGH THIS EVENING.



AVIATION...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 22025.





...THOMPSON

