Incoming Storm System, 12/15/18

From NOAA Forecast Discussion - button up!
(new editing format by WP is resulting in formatting issues. 
I hate when wp decides to change what works for something that doesn’t)
”Unlike previous storm system this one will have plenty of moisture to work with. 
Latest TPW imagery puts values of 1-1.5" or 150-200% percent of normal. 
Simply put there is moisture to work with. 
Atmospheric River guidance has been rather consistent 
for several days now indicating IVT over 500 kg/m/s, 
which would fall into the moderate category 
and be one of the stronger ARs of the 2018 season. 

Once the upper level TROUGH arrives Sunday afternoon it will 
help to push the FRONT through the region. 
Additionally, the upper level TROUGH will increase upper level support and increase overall INSTABILITY.
Model guidance shows rather decent surface and mid- level INSTABILITY Sunday afternoon through early Monday. 
Decided to add a 15-20% CHC of thunderstorms with the FROPA. 
It should be noted that the Storm Prediction Center 
has a large portion of CA in a general mention 
of thunder Sunday into Monday. 
Given the landfalling AR and convective potential 
there could be a brief period of moderate to heavy rainfall 
leading to minor flooding/ponding on roads and urban areas.  
A more showery regime will set up late Sunday night over northern areas behind the FRONT and then slowly spread S and E Monday afternoon. 
Rainfall totals tonight through Monday will be greatest over the North Bay and coastal mountains 1-3" - locally 3+" North Bay Peaks and Santa Lucias.” 
Repeat: Locally, over 3” in the Santa Lucias.