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Forecast Discussion - Convective Outlook

   SPC AC 160545

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1145 PM CST Tue Jan 15 2019

   Valid 161200Z - 171200Z


   Isolated thunderstorms are likely late Wednesday across parts of
   northern and central California. Gusty winds may accompany this


   00z short-range model guidance is in general agreement that a strong
   short-wave trough will approach the northern CA coast by 17/06z with
   substantial height falls expected to spread inland during the
   overnight hours. Large-scale forcing for ascent will likely
   encourage weak elevated convection ahead of the front during the
   early evening but this activity should struggle to attain heights
   necessary for lightning. However, significant mid-level cooling will
   aid destabilization as lapse rates steepen just ahead of a
   pronounced surface front that should move onshore around 06z.
   Forecast soundings along the northern CA coast suggest near-surface
   based buoyancy will evolve along the front which will likely result
   in one or more strongly-forced bands of convection. Very strong
   southwesterly flow is forecast just off the surface and there is
   some concern strong winds may mix to the surface with the frontal
   convection. NAM forecast sounding at SFO at 17/06z exhibits SBCAPE
   on the order of 300 J/kg with 50kt southwesterly flow at 1k feet
   AGL. At this time will not introduce MRGL for gusty winds but if
   sufficient instability can materialize a few strong storms may be
   possible with the frontal convection.

   ..Darrow/Leitman.. 01/16/2019