What you need to know about storm heading to Bay Area this weekend

SAN FRANCISCO (KGO) -- An early season, and strong storm by September standards, arrives late Saturday night.

TIMELINE: Here's when much-needed rainfall arrives in Bay Area this weekend

ABC7 News Meteorologist Mike Nicco says to expect a steadier rain across our coastal mountains and Marin County while waves of showers rain elsewhere. Some showers could produce lightning and downpours.

The bulk of our wet weather falls Sunday. Nicco suggests it is a good idea to have an alternative plan if your activities take you outside.

Monday features scattered showers and a slight chance of thunderstorms. An isolated shower and thunderstorm could develop Tuesday as the storm exits.

LIVE: Track real-time temps, rain and more around Bay Area

Rainfall estimates are still hard to gauge this far in advance. Medium range forecast models range from .25" to near 2.5".

High-resolution models come into range Friday. Nicco says that hopefully, their guidance is more consistent.

Expect more updates as we get closer.

Watch the latest AccuWeather forecast and take a look at recent weather stories and videos.