Officials with the National Weather Service are predicting rain toward the end of the week in the Bay Area.
Rain could move into the area Thursday night and spread south from the North Bay on Friday.
This is the rainy season's first atmospheric river, which is region in the atmosphere responsible for bringing water vapor from the tropics.
Weather officials said that it's important to prepare for the rain by changing windshield wipers, checking tires, fixing leaks at home and finishing outdoor projects.
The rain will mean slick roads, decreased visibility, ponding on roads and gusty winds in the area's hills and mountains and along the immediate coast.
Weather officials are confident that the rain is coming but are less sure of its timing and the amount.