ABC7 Meteorologist Mike Nicco says some parts of the Bay Area will get over an inch of rain by Friday. That's the most rain in a single day for the Bay Area since March 12.
WATCH: Your complete Bay Area AccuWeather forecast
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.
For the latest weather information, download the ABC7 Weather App and enable push alerts to get breaking updates as they happen.
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.
1st significant series of storms on the way to our neighborhoods. They rank a 2 & 1 on our Storm Impact Scale. Some hints so you're ready. pic.twitter.com/oct4YobdZt— Mike Nicco (@MikeNiccoABC7) October 10, 2016