Heavy showers and possible thunderstorms are in the forecast for the state through Sunday and bad weather is expected to linger through the early part of next week, the National Weather Service said.

The wet weather is predicted to sweep through Kaua'i tomorrow and then move to O'ahu Saturday and to Maui County Saturday and Sunday, said lead forecaster Bob Farrell.

Farrell warned a flash flood watch for Kaua'i and O'ahu could be posted this weekend depending how bad the rain gets.

A low-pressure system forming northwest of the Hawaiian Islands is causing a kona storm and the rainy weather, Farrell said.

"It looks like we'll have a wet Easter," said forecaster Sam Houston.

Houston said the storm would likely increase surf conditions on north and northwest facing shores, with wave faces 15 feet or higher, but said the waves could be messy as the storm passes through.

Runoff from streams and rivers will likely make surrounding ocean waters murky again on Kaua'i so beachgoers should be careful, Farrell said.

"Rain washes things into the water," Farrell said. "I think that's what happened last weekend on Kaua'i."