A series of warm atmospheric rivers will bring moderate to heavy
rain to the Valley, foothills, and mountains the week of Christmas.
The prolonged period of rain will bring the risk of flooding to the
Sacramento Valley, northern San Joaquin Valley, northern Sierra
Nevada and adjacent foothills, as well as the Coastal Range.

* WHAT...Flooding caused by excessive rainfall continues to be
possible.

* WHERE...A portion of northern California, including the following
areas, Carquinez Strait and Delta, Sacramento Valley, Motherlode,
Mountains Southwestern Shasta County to Western Colusa County,
Northeast Foothills, Northern San Joaquin Valley, and Shasta Lake
Area / Northern Shasta County.

* WHEN...Through Friday afternoon.

* IMPACTS...Excessive runoff will result in rises along area rivers,
creeks, streams. Small streams and creeks may rise out of their
banks. Flooding may occur in low-lying, poor drainage, and urban
areas. Mudslides and rockslides may occur in mountain and foothill
areas.

* ADDITIONAL DETAILS...
- Periods of moderate to heavy rain are forecast the week of
Christmas. Debris flows are not expected over recent burn
scars in northern California, but do anticipate enhanced
runoff in/below scars.
- http://www.weather.gov/safety/flood
                                            

* WHAT...Heavy snow expected. Total snow accumulations of 1 to 3
feet above 4500 feet, with locally higher amounts at peaks. Up to
1 foot between 3500 to 4500 feet. Wind gusts up to 60 mph.

* WHERE...Burney Basin / Eastern Shasta County, Mountains
Southwestern Shasta County to Western Colusa County, and Shasta
Lake Area / Northern Shasta County Counties.

* WHEN...Until 10 PM PST Friday.

* IMPACTS...Dangerous travel conditions with chain controls and road
closures. Localized tree damage, power outages, and low visibility
due to the combination of heavy wet snow and strong winds.

* ADDITIONAL DETAILS...Snow levels will be above 4500 feet today,
then drop to 3500 feet by tonight. Snowfall rates up to an inch
per hour at times.