An upper-level low is expected to produce locally heavy showers with a possibility of thundershowers as it passes across state over the next two days, the National Weather Service reported.

A low, also called a cold-core cyclone, is a cyclone aloft that has an associated pool of cold air and occurs at a high altitude.

Water vapor imagery indicates that the low is centered about 350 miles east-northeast of Hawaii island and has been drifting slowly westward.

According to NWS, the threat of heavy rainfall and possible thunderstorms will likely begin over Hawaii island between Sunday and Monday and will reach the middle of the island chain by Monday evening.

Rainfall is most likely over windward and mauka areas.

Meanwhile, a high-pressure system north of the state is expected to keep tradewinds blowing through the early part of the week.