Here is how a lot rain is forecast to fall within the San Francisco Bay Space on Saturday

The San Francisco Bay Area was soaked in sunshine on Friday afternoon, but forecasters say much-needed rain is on the way Saturday.

A weak weather system is expected to arrive tomorrow morning and deliver light, widespread rain into the afternoon, the National Weather Service said.

“The moisture tap with this system is greater and limiting rainfall potential,” the weather service said in its forecast.

A tenth to a quarter of an inch is forecast for areas across the Bay Area, Roger Gass, a meteorologist with the weather service said.

“There is always the possibility that some locations will see less than a tenth of an inch, especially in the three inland valley locations, and some spots could see a little more than a quarter of an inch,” Gass said. “It’s not much, but we’ll take what we can get.”

Cold air aloft in the atmosphere on Saturday could cause short spurts of moderate rainfall and even hail, and there’s a 10% chance of thunderstorms, the weather service said.

“The system does have a little bit of oomph to it,” Gass said. “There’s some instability that could cause an isolated thunderstorm, but the possibility remains very low.”

Showers will subside quickly by Saturday evening and dry conditions are expected overnight, but “there will be a nip in the air,” the weather service said. Widespread 40s are forecast overnight with some inland locations even getting into the 30s.

Temperatures are expected to rebound on Sunday and Monday marks the start of an early season heat wave with high pressure building over the eastern Pacific Ocean.

The weather service is forecasting temperatures in the mid-to-high 70s for inland valleys and mid-60s for coastal areas on Monday.

Tuesday and Wednesday will likely be the hottest days of the week, with more locations breaking into the 80s.

“Either of those days could be the peak of the warming for this event,” Gass said.