SPC AC 040535

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1135 PM CST Sat Dec 03 2022

   Valid 041200Z - 051200Z

   ...NO SEVERE THUNDERSTORM AREAS FORECAST...

   ...SUMMARY...
   Isolated thunderstorms are probable across parts of northwest
   California and the far southern Oregon coast through tonight.
   Sporadic lightning flashes are also possible across the Desert
   Southwest this afternoon.

   ...Synopsis...
   Latest water-vapor imagery depicts a broad upper ridge over the Gulf
   of Mexico/southern CONUS with an upper low off the northern
   California coast. This regime is expected to evolve slowly over the
   next 24 hours as the upper wave gradually moves onshore. As this
   occurs, cold temperatures aloft will overspread deep Pacific
   moisture sampled by 00 UTC soundings along the West Coast. This
   thermodynamic regime is already supporting sporadic lightning
   flashes off the CA coast under the low, and will likely maintain
   adequate buoyancy for thunderstorms through tonight across northwest
   CA and perhaps the far southern OR coast. Despite the shallow nature
   of the convection, strong speed shear within the CAPE-bearing layer
   may support weakly organized cells capable of sub-severe hail this
   afternoon; however, the potential for intense, severe convection
   appears low.

   Across the Desert Southwest, a persistent stream of Pacific moisture
   from Baja California will maintain nearly saturated profiles across
   southern AZ and southwest NM. Weak isentropic ascent combined with
   muted daytime heating and modest cooling aloft will likely yield
   sufficient buoyancy for sporadic lightning flashes this afternoon
   and early evening. Slim CAPE profiles and weak ascent will limit the
   overall intensity and longevity of convection.

   ..Moore/Guyer.. 12/04/2022

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