SPC AC 211250

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0650 AM CST Sat Dec 21 2024

   Valid 211300Z - 221200Z

   ...NO SEVERE THUNDERSTORM AREAS FORECAST...

   ...SUMMARY...
   Isolated thunderstorms are possible this morning into early
   afternoon across parts of coastal Oregon and northern California.

   ...Coastal OR/northern CA...
   A potent mid to upper-level shortwave trough will move ashore the
   northern CA/OR coast and continue northeastward into the southern
   Canadian Rockies/northern Rockies vicinity through late tonight. 
   Weak thunderstorm activity embedded within a warm-air advection rain
   shield will continue moving into the coastal range mountains this
   morning before outrunning the inland penetration of scant
   instability.  The corridor of thunderstorms will probably shift
   north along the coast into OR by midday into the early afternoon in
   association with the mid-level cold pocket encroaching on the OR
   coast.  Elsewhere, quiescent weather or stable conditions will
   preclude thunderstorm development over the remainder of the
   contiguous United States.

   ..Smith/Goss.. 12/21/2024

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