Tropical Flow of Moisture Delivers Huge Quantities of Water to California

While El Niño disappointed California last year, La Niña – a weak one – is delivering huge quantities of water this season and the height of it may be this week.

At least four feet of snow will fall on the Sierras by the weekend and a lot of rain will be falling elsewhere. The moisture is coming in so fast and furiously that there will be a significant flooding threat for the next couple of weeks.

First off, the snow that has fallen is already impressive:

And, add to that through Sunday with an additional 60"+ as shown here in the yellow shades:

Weather5280 Models: GFS Snowfall 10:1 Ratio

That's just snowfall for the week. There's also a lot of rain to fall. Consider just this upcoming weekend for areas near Sacramento.

The rate at which the moisture is falling, more than 2-inches per hour in some cases in the mountains, is a serious threat to travel and will become a flooding risk throughout the weekend and for the next week at least.

Considering all water, rain and snow, here is the total precipitation that may fall through Sunday evening:

Weather5280 Models: GFS Precipitation
Yes, that's showing us 3 to 5 inches off the mountains and nearing 20 inches on the mountains.

This will tremendously improve the drought situation across northern California which sits near extreme levels toward central and southern regions.

UNL Drought Monitor

Snowpack in the Sierras, to date, has been below average. This week's flow of plentiful tropical moisture will boost those averages.

Further, with snowfall chances continuing the snow totals from now to mid-January may well surpass 100". Rain chances, albeit not as intensely, will continue through the next two weeks also. Some of the lower country will close in on 5 to 10 inches of rainfall.

Southern California won't have these huge precipitation totals, but even far southern counties of the state may see upwards of an inch of moisture through the mid-month.