Weather conditions over the islands are extremely unstable, thanks to an upper level trough just southwest of the state. The disturbance will keep the threat of locally heavy rain and thunderstorms for parts of the state into Friday, with a flash flood watch remaining posted for all islands except the Big Island.
There’s still uncertainty in the short-term forecast, but Kauai and Oahu will have the highest chance of seeing heavy showers and thunderstorms Thursday night into Friday as the trough and the area of increased moisture moves westward. However, there will be enough instability for another day of isolated afternoon thunderstorms on the Kona side of the Big Island.
As we head into the weekend, we should have slow improvement, with showers becoming more focused on windward and mauka areas. High clouds will linger over much of the state Saturday and diminish Sunday, with more sunshine and drier conditions by Monday.
In surf, the current northwest swell will decline over the next few days, but some overhead sets are still possible in the morning for north shores. Surf along east shores will increase into next week due to strong trade winds developing upstream. Small background swells are expected for south shores.