High winds downed a utility pole in Kakaako and knocked out power in Alewa Heights, Ewa Beach and Hawaii Kai on Sunday as an unstable weather system continued to prove disruptive in the skies and on the ground.

The fallen pole cut service to about 100 customers and prompted police to close Kawaiahao Street between Ward Avenue and Cummins Street starting at about 12:30 p.m. Hawaiian Electric Co. spokesman Darren Pai said repair work was expected to continue overnight.

High winds were also blamed for an earlier power failure in Alewa Heights that affected 600 customers. Areas of Ewa Beach and Hawaii Kai also lost electricity on Sunday although it was unclear how many homes and businesses were affected.

Honolulu Fire Department personnel responded to a call in Wahiawa involving a roof that had blown off a carport around 12:50 p.m. Sunday. HFD spokesman Capt. Terry Seelig said the roof was apparently older and had been in moderate disrepair prior to the incident.

HFD personnel helped clean up the debris and secure the carport area.

The National Weather Service issued a flash flood watch for all islands though 6 a.m. today due to a "moist and unstable atmosphere" that is expected to cause locally heavy showers and thunderstorms across the state. In addition, the weather service issued or extended wind advisories for Lanai, Oahu and the summits and upper slopes of Mount Haleakala on Maui through 6 a.m. Monday.

The weather service predicted heavy rain would focus on windward coasts and mountain slopes, but warned that heavy runoff could also occur in streams leeward of the mountains. It cautioned people to stay away from streams, drainage ditches and low-lying areas prone to flooding.

The state Department of Health’s Clean Water Branch issued a brown-water advisory on Sunday for Maui and Hawaii island due to heavy rain. The public is advised to stay out of floodwaters and storm water runoff due to possible overflowing cesspools or sewer manholes, pesticides, animal fecal matter, dead animals, pathogens, chemicals and associated flood debris.

People are further advised to stay out of coastal waters that are brown or cloudy.

On Sunday, health officials cautioned people to stay out of Waolani Stream in Nuuanu after 500 gallons of waste water spilled into the stream through a storm drain. The spill was halted, but people are still advised to stay away until warning signs are removed.