

492 

WWUS20 KWNS 192104

SEL8

SPC WW 192104

MTZ000-200400-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 328

NWS STORM PREDICTION CENTER NORMAN OK

305 PM MDT WED JUN 19 2013



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

  CENTRAL AND NORTH CENTRAL MONTANA



* EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 305 PM

  UNTIL 1000 PM MDT.



* PRIMARY THREATS INCLUDE...

  SEVERAL LARGE HAIL EVENTS WITH A FEW VERY LARGE HAIL EVENTS TO 2

    INCHES IN DIAMETER POSSIBLE

  SEVERAL DAMAGING WIND GUSTS TO 70 MPH POSSIBLE

  A FEW TORNADOES POSSIBLE



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 90

STATUTE MILES EAST AND WEST OF A LINE FROM 40 MILES NORTHEAST OF

CUT BANK MONTANA TO 60 MILES WEST SOUTHWEST OF LEWISTOWN MONTANA.

 FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU8).



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 327...



DISCUSSION...CONVECTION WILL INCREASE IN COVERAGE/INTENSITY THROUGH

THE AFTERNOON AS SURFACE HEATING CONTINUES ALONG AND E OF A STALLED

FRONT...AND IN ADVANCE OF A MIDLEVEL TROUGH ROTATING NNEWD FROM ID.

STEEP LAPSE RATES/MODERATE INSTABILITY AND MODERATELY STRONG

VERTICAL WIND SHEAR WILL SUPPORT SUPERCELLS THE NEXT FEW HOURS...AND

EVENTUAL GROWTH INTO CLUSTERS/LINE SEGMENTS LATER THIS EVENING.

LARGE HAIL AND DAMAGING WINDS WILL BE THE MAIN THREATS...THOUGH A

TORNADO OR TWO CANNOT BE RULED OUT IF A SUPERCELL IS ABLE TO REMAIN

DISCRETE AND MOVE ALONG THE STALLED FRONT.



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 19030.





...THOMPSON

