Small-craft advisories are in effect for the Kaiwi Channel, windward and leeward waters around O'ahu, and waters around Kaua'i, Maui and the Big Island.

The National Weather Service has posted the small-craft advisories through 4 a.m. tomorrow, expecting that a high-pressure system northeast of the Islands will build southward. Strong trade winds are expected to affect all coastal waters today and tonight.

The small-craft advisories also include Kaua'i northwest, windward and leeward waters and the Kaua'i Channel; Maui County windward and leeward waters; and all Big Island waters.

A small-craft advisory is issued when winds speeds are expected to reach 25 to 33 knots and/or seas are greater than 10 feet, creating hazardous conditions for small vessels.