The wet weather is being welcomed after the driest start to the rainy season in 60 years.

California state in the United States prepares for another round of heavy rains, following flooding across its central parts last week.

Heavy downpours in central California led to the closure of roads and schools, and homes were flooded. A major highway in Monterey County was impassable, with water more than a metre deep.

Los Angeles and San Diego received about 25mm of rain, which triggered flooding of some streets and freeways. Even heavier rain fell over the mountains, with reports of rock and mudslides in southern areas of the state.

The next Pacific storm is moving into California this weekend, and is expected to bring several metres of snow to the Sierra mountain range, and the risk of flash flooding.

Unlike the last system, this one will bring the worst weather to the northern parts of the state, with as much as 145mm of rain accumulating throughout the weekend.

The National Weather Service has issued a flash flood watch for parts of northern California, with areas recently burned by wildfires particularly vulnerable.

Weekend travel plans could be affected, with winter storm warnings in effect across the Sierra mountains.

Up to the last week in November, parts of northern California were experiencing their driest start to the rainy season in 60 years.

Two days before Thanksgiving Day, San Francisco picked up significant rain in nine straight days, and Santa Rosa nearly cleared its seasonal deficit in the same duration.

Despite the threat of flooding, more rain in the forecast bodes well for California’s water supply. As the rainy season gets under way, most reservoir levels across the state are running higher than average for early December.

The Sierra snowpack is also running well above average for this time of year, according to the California-Nevada River Forecast Center.

Accumulated snow in the winter months will produce good snowmelt in the spring and summer. The California Department of Water Resources says about 30 percent of the state’s water supply comes from snowmelt.