Windward and mauka showers are expected to pick up on Oahu and Kauai today as Monday’s breezy tradewinds back off to moderate levels, according to the National Weather Service.

At the same time, the large north-northwest swell that was pounding Hawaii’s shores with up to 25-foot waves Monday is expected to taper off today and shift out of the north. Forecasters said they expect to downgrade the high-surf warning that was in effect Monday to advisory levels today.

But there is also the potential for a sizable northwest swell building Thursday and continuing through the weekend, officials said.

In addition to an increase in windward and mauka showers over the next couple of days, look for a return of more typical tradewind weather through the end of the workweek, forecasters said.

Weather officials said longer-range guidance shows another weakening cold front approaching the islands from the north Thursday and Friday and producing more wet weather by the weekend, mainly over the eastern and southeastern slopes of the Big Island and near Kauai and Oahu as the front moves across the island chain.

Cold air moving in with the front this week will cause wind directions to change from an easterly to a more southerly direction by Friday, resulting in possible showers in the eastern and southeastern parts of the Big Island as early as Friday.

As for the surf, forecasters said east-facing shores will be increasingly exposed to a north swell wrap Tuesday through Thursday, making surf heights swell a bit higher.

A small south swell is expected to gradually decline today, leaving mainly background swell for south- facing shores thereafter.

A small-craft advisory was expected to remain in effect through today for coastal waters exposed to the north-northwest swell, mainly in windward and northern waters. As it transitions to northerly and gradually diminishes today and Wednesday, the swell has the potential to cause moderate harbor surges in Hilo and Kahului, forecasters said.