Oahu's usual breezy trade winds are set to continue today, with a gradual weakening expected by tomorrow. Windward and mauka regions will likely see showers as these winds persist, with a shift leading to fewer windward showers and an increased chance of afternoon interior showers through the later part of the week, according to the National Weather Service in Honolulu.
In an evolving weather scenario, a high pressure centered northeast of the state is maintaining the strong trade winds for now. These, coupled with a weak upper-level low contributing a touch of instability, means some areas will see brief but potentially heavy showers. With scattered showers moving in, the high-pressure system is expected to sustain these conditions through tonight, focusing precipitation mainly on windward slopes and coasts. Amid this, aviation alerts have been sounded for moderate turbulence below 8,000 feet over the leeward sides of the islands, likely to continue into the evening or longer.
Towards the middle of the week, a shift in winds is anticipated as a cold front stalls out northwest of the state. This will allow for the development of lighter southeast winds, which in turn permit land and sea breezes to kick up beginning Wednesday. By the weekend, these light winds could lead to either a land/sea breeze pattern with subdued diurnal convection or a hybrid sea breeze pattern. This could focus the showers over the western slopes of each island. Mariners take note: A Small Craft Advisory remains in effect until the early hours of Tuesday for specific areas due to the enduring trade winds.
A small northwest swell today and tonight will bring higher surf to north and west-facing shores, but it should ease by mid-week. Another swell is expected Thursday, possibly bringing advisory-level surf through Friday before calming down over the weekend. East shore surf will stay rough today due to trade winds, but should settle later in the week as winds die down. Southern shores will see small waves for now, with a chance of seasonal-size surf by the weekend.
