Heavy rain and mountain snow forecast for northern and central parts, with river and urban flooding likely in Los Angeles

After prolonged heavy rainfall and devastating flooding across the Pacific north-west in the past few weeks, further flood watches have been issued across California through this week.

With 50-75mm (2-3in) of rainfall already reported across northern California this weekend, a series of atmospheric rivers will continue to bring periods of heavy rain and mountain snow across the northern and central parts of the state, with flood watches extending until Friday.

Cumulative rainfall totals are expected to widely exceed 50mm (2in) across a vast swathe of California by Boxing Day, but with totals around 200-300mm (8-12in) possible for the north-western corner of California and western-facing slopes of the northern Sierra Nevada mountains.

Los Angeles could receive 100-150mm (4-6in) of rainfall between Christmas Eve and Christmas Day, which could make it one of the wettest Christmases on record for the city. River and urban flooding are likely – particularly where there is run-off from high ground – with additional risks of mudslides and rockslides in mountain and foothill areas.