Weather forecasters have sounded an early warning for what could shape up to be a very wet weekend as the remnants of former Tropical Storm Howard move over the state.

The National Weather Service issued a flash flood watch for all islands from Sunday morning through Monday afternoon as some storms could produce heavy rain and thunderstorms.

On Oahu there’s a 90 percent chance of precipitation Sunday with possible rainfall amounts of 1 to 2 inches.

“We do not expect the same level of rainfall as we did with Tropical Storm Darby, but with the ground still saturated from that event, heavy rains could still lead to flooding, road closures and possible utility outages,” said Honolulu Mayor Kirk Caldwell in a statement Friday.

A high-surf advisory is in effect from noon today through 6 a.m. Sunday, forecasters reported.

A surface low associated with Howard will build today, producing advisory-level surf across Hawaii island and Maui County by morning and on Oahu and Kauai by afternoon.

Swells of 6 to 9 feet are expected to build along east-facing shores Saturday afternoon and peak Saturday night.

As Howard’s remnants pass over the islands Sunday, elevated surf could persist along east shores of Oahu and Kauai.

The Department of Environmental Services and Department of Design and Construction will be monitoring sewer flows throughout the storm, while Oahu Transit Services is prepared to move Handi-Vans and buses from their overnight storage lot in the event of heavy rain.

Another system, Tropical Storm Ivette, could bring more muggy conditions and rain as early as Wednesday.

As of 5 p.m. Friday, Howard was about 550 miles east-northeast of Hilo while Ivette was about 1,510 miles east-southeast of Hilo.

Ivette’s winds increased to 60 mph as the storm moved west at 13 mph late Friday morning. Ivette could still strengthen slightly but is no longer expected to become a hurricane.