MESOSCALE DISCUSSION 1317
   NWS STORM PREDICTION CENTER NORMAN OK
   1204 PM CDT FRI JUN 29 2007
   
   AREAS AFFECTED...PARTS OF WRN MT
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 291704Z - 291830Z
   
   TRENDS ARE BEING MONITORED FOR AN INCREASING SEVERE THREAT AND THE
   POSSIBILITY OF A WW.
   
   A VIGOROUS UPPER TROUGH CONTINUES TO PROGRESS INTO THE PACIFIC
   NORTHWEST COAST...WITH DIFLUENT/DIVERGENT DOWNSTREAM FLOW
   OVERSPREADING THE NORTHERN INTERMOUNTAIN REGION/NORTHERN ROCKIES. 
   AND...IT APPEARS THAT A ZONE OF STRONGER FORCING WILL SHIFT ACROSS
   THE MOUNTAINS OF WESTERN MONTANA BETWEEN NOW AND 18-20Z.  AS THIS
   OCCURS...CONVECTIVE DEVELOPMENT IS EXPECTED TO INITIATE/INTENSIFY
   ALONG THE HIGHER TERRAIN...BEFORE DEVELOPING NORTHEASTWARD TOWARD
   SOUTHERN ALBERTA/SASKATCHEWAN...AS SOUTHWESTERLY MID-LEVEL FLOW
   STRENGTHENS IN EXCESS OF 50 KTS.  DEEP LAYER SHEAR WILL BECOME
   INCREASINGLY SUPPORTIVE OF SUPERCELLS...PARTICULARLY TO THE
   NORTHWEST OF GREAT FALLS...ACROSS THE CHOTEAU/CUT BANK AREAS...
   WHERE LATEST RUC GUIDANCE INDICATES THE ENVIRONMENT IS ALREADY
   BECOMING MODERATELY UNSTABLE.  LARGE HAIL WILL LIKELY ACCOMPANY
   ACTIVITY...WITH A RISK FOR DAMAGING WIND GUSTS...POSSIBLY AN
   ISOLATED TORNADO.
   
   ..KERR.. 06/29/2007
   
   
   ATTN...WFO...TFX...MSO...
   
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