Surf is expected to rise to 30 to 40 feet Wednesday, prompting the National Weather Service to a high surf warning from midnight tonight until 6 a.m. Thursday for north- and west-facing shores of Oahu, Kauai County and Molokai and north shores of Maui.

A high surf advisory is posted for west shores of Hawaii island.

Forecasters said a large northwest swell will bring warning-level surf of 20 to 25 feet early Wednesday, rising to 30 to 40 feet by the afternoon.

The surf is expected to slowy trend down below advisory level as early as Thursday night.

“Only highly-experienced persons should enter the water,” the weather service said. “Inexperienced persons should remain off beaches and adjacent beachfront areas. Large breaking surf, significant shorebreak and dangerous currents make entering the water very hazardous. Anyone entering the water could face significant injury or death.”

A weak cold front moving over the islands tonight and Wednesday could also bring scattered showers to the North Shore.

Forecasters are calling for an increased chance of showers, especially for north-facing slopes.

Lows are expected to be in the 60s tonight as north winds keep temperatures cool.

Tradewinds are expected to return Thursday and Friday, but winds will likely become light and variable again this weekend.