Here’s the NOAA Forecast. Take a look:
Looks as though there could be 6 inches of rain. That’s a bunch as the Lake Oroville Watershed is huge.
Lake Oroville's capacity (assuming a lake level of 850 ft. to start) is large enough that, at that time, an additional 10" of rain in the Lake Oroville "catchment basin" = emergency spillway should not be topped, but it might get dicey.
Now, note this excerpt from the current NWS forecast discussion (bold highlights are mine):
Discussion... Take this afternoon and evening to make final preparations ahead of the incoming storm with flooding, strong winds and heavy snow. If you were given less than 15 minutes to evacuate your home would you have everything you need and gas in your vehicle? If roadways are closed from flooding, downed trees, or mudslides, do you have enough supplies to last you several days? If there are widespread power outages that last more than a day would you be prepared? If you are stuck on a road, do you have supplies in your car?
Northern California has become very vulnerable after being hit continuously with storms since early January and we want all residents in our region to plan ahead and be prepared.
Another very wet pattern starts later tonight with precipitation lingering into Wednesday. However, the strongest storm will be Monday into Tuesday when we expect the greatest precipitation and strongest winds. An atmospheric river will bring another plume of intense moisture to the west coast. Models vary slightly on where this plume will hit directly, but we have good confidence that it will be somewhere in our CWA. Another concern is that this plume could stall for a period of time which would significantly increase flooding issues for wherever that stall occurs. Keep in mind that significant flooding can also occur outside of this intense moisture plume since soils are so saturated and there will be added stress to levees, rivers and streams. That`s why residents should stay tuned to social media, news and updates during the storm so they can act quickly if needed.
Specifics of the Monday-Tuesday storm: Precipitation amounts could range 1 to 3 inches in the valley with up to 10 inches along the Western Sierra Slopes. Remember that runoff from the mountains will eventually flow downstream and add impacts to the valley. Snow amounts will be heaviest above 6000 feet with a range of 2-5 feet of new snow but we could see up to a foot of snow down to 5500 feet. Snow levels will be near or slightly above Sierra pass levels on Monday, then lower below pass levels on Tuesday. Strong wind gusts in the valley and foothills are forecast to range 45-65 mph with stronger winds over mountains Monday afternoon into Monday night.
The last big rainmaker stalling, and lack of maintenance of the spillways @ Oroville, was most of what caused the 1st round of major problems...