Old Man Atmospheric River

He just keeps rollin' along (from Dr. Greg Forbes):

A long plume of moisture is headed into California as I write this on Friday December 17 and threatens to bring up to a foot of rain on foothills and possibly up to 15 feet of snow at high altitudes by the middle of next week. Please monitor updates in the forecasts on The Weather Channel and on Weather.Com.

A generic name for this plume of moisture is "atmospheric river", as shown on the satellite image below from Friday afternoon . It's a "fire hose" of atmospheric moisture. This one is oriented almost west-to-east. Had it been heading more northeastward from near Hawaii I would have called it a "pineapple express." Still, it is loaded with moisture. With it possibly blasting California through Wednesday, the precipitation will add up. [...]

The prolonged and at times heavy rain will accumulate and lead to threats of flooding and mudslides that increase with time, especially on the west and south-facing California foothills. At high altitudes in the mountains, many feet of snow will fall and winds may gust over 70 mph, giving whiteout conditions and possibly avalanches. A summary of the potential impacts is shown below.

This is a dangerous weather situation. Pay close attention to the weather conditions. Stay safe!

Looks like we have a 60%+ percent chance of rain every day until Wednesday. Northern California will get several more days after that. You'll be able to recognize Californians by the moss growing on their north side. That and the hillsides that fill their bonus rooms.