WUWT contributor Dr. Ryan Maue writes on his Twitter feed:
Can't ask for better setup for enormous rainfall totals over NorCal & now linto Bay Area in 5+ days
Looking at the model output below, I tend to agree, if the pattern holds. It sets up Northern California for the perfect orographic lifting enhancement in the Sierra Nevada mountain range that will not only provide a bounty of liquid precipitation, but a significant boost to the well below normal California snowpack.
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Most or northern California will get some benefit from this "super soaker" storm:

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The Quantitative Precipitation Forecasts show some parts of Northern Calfornia getting as much as 20″, along with many mountain areas getting 5″ or more.

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How much will be snow? That's anyone's guess at this time, it depends entirely on how much air and moisture is advected into the low pressure system to collide with colder air.

We'll know more as we get closer to the event.

Graphics courtesy of Dr. Ryan Maue and WeatherBell.com