Kauai and Niihau are under a flash flood watch, but a flood advisory has been canceled for Oahu.
The flash flood watch is in effect through 6 a.m. Tuesday as a cold front approaching from the north carries the possibility of heavy rain and thunderstorms.
The National Weather Service issued the watch at 6 a.m. Sunday.
Heavy or persistent rains will cause streams to rise even in areas where rain is not occuring, the agency warned. Heavy rain will also create slick roadways and reduce visibility, making driving hazardous, the weather service said on its website.
The agency warned against camping or hiking near streams.
The potential for thunderstorms on Kauai is particularly strong tonight.
Moderate to heavy showers over Oahu this morning had prompted forecasters to extend the flood advisory for Oahu to 7:30 a.m., but it has since been canceled.
Meanwhile, the weather service issued a high wind advisory for Mauna Kea and Moana Loa, forcasting southwest winds of 25 to 35 mph and gusts of more than 50 mph. That advisory also remains in effect through 6 a.m. Tuesday.
The strongest winds are expected to today.