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 is possible. * WHERE...A portion of northern California, including the following areas, the Sacramento Valley, northern San Joaquin Valley, Delta region, Sierra Nevada and adjacent foothills, and Coastal Range. * WHEN...From Saturday afternoon through next 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, but do anticipate enhanced runoff in/below scars. - http://www.weather.gov/safety/flood