A flash flood watch remains in effect for all of the Hawaiian islands through this afternoon, the National Weather Service says.

Unstable atmospheric conditions are combining with a southeast flow, bringing in lots of moisture to pave the way for conditions that could lead to flash flooding, weather officials said.

Residents and visitors are warned to avoid camping or hiking near streams and low-lying areas.

A surface ridge will remain over the islands through Sunday, bringing light southeast winds, muggy conditions and volcanic haze. A trough aloft will allow for a slight chance of thunderstorms through Sunday. 

The atmosphere will become more stable early next week as the trough aloft moves away to the northeast, the weather service says. A high building northeast of the area will bring light trade winds Monday and locally breezy trades by late next week.

The flood advisory for Maui was upgraded into a flash flood warning until 2:45 a.m.

The weather service said radar was showing heavy rain at Kipahula and Hamoa.

Hana and Kaupo were included in the advisory.

The weather service urged people on Maui to stay away from streams, drainage ditches and other low-lying areas probe to flooding.

The weather service also has issued a flood advisory for Hawaii island until at least 2:15 a.m.

At 11:06 p.m., radar showed heavy rain near Pahoa. The advisory includes Mountain View, Keaau, Kapoho, Hawaiian Paradise Park, Hawaiian Beaches and Glenwood.