The National Weather Service is warning that “quite an active next several days” can be expected across the island chain — including the possibility of hail — as a strong storm system approaches and moves through the region.

Showers and thunderstorms are forecast for Sunday as kona winds from the southwest strengthen in advance of a strong cold front expected to move down the island chain from the northwest late Sunday night through Monday evening.

A high-wind watch will be in effect from 6 p.m. Sunday through 6 p.m. Monday for all islands due to strong and potentially damaging winds associated with the storm system. The National Weather Service said winds are expected to peak Sunday night and Monday, potentially at warning levels, with the strongest winds expected in windward locations.

Kona winds should increase to 15 to 25 mph Sunday afternoon and ramp up to 20 to 35 mph after midnight. Monday should be “very windy,” the service said, blowing from the southwest to west at 20 to 40 mph with gusts to 60 mph, with scattered thunderstorms and locally heavy rainfall possible.

Behind the cold front, breezy to locally windy conditions are expected to continue through Tuesday before easing off. Light to at times moderate kona winds will then prevail Wednesday through Friday, with light to moderate trades to return for the weekend, according to forecasters.

The powerful low sending the cold front over the islands is forecast to produce a series of extra-large northwest swells with surf heights of 10 to 14 feet Sunday on Oahu’s north-facing shores and 7 to 10 feet on west-facing shores, with 1- to 3-foot waves on south-facing shores.

The NWS says that could be followed by a large west-northwest swell during the second half of next week.