Heavy rains hit part of the Hawaiian islands Sunday, prompting a flood advisory on Hawaii island and Oahu  and flooding in Kalihi.

A storm-related power outage occurred in Waiakamilo for about 30 minutes, ending at 5:10 p.m., Hawaiian Electric said.

The rain made for tricky driving conditions on the H-1 freeway, where water ponded in the westbound lanes near the Liliha Street underpass. Many surface streets also were covered by several inches of water.

"At 4:57 p.m., radar showed that most of the heavy rain on Oahu was diminishing, but showers and ponded water are still being reported on roadways in Honolulu, mainly in the Kalihi and Iwilei areas," forecasters said as they extended the Oahu advisory from 5:15 p.m. "Stream levels remain elevated, thus the flood advisory is extended until ponding and stream levels subside."

By this evening, the muggy, rainy weather is expected to be west of Oahu.

The tradewinds will gradually strengthen later in the week, and may be locally breezy by next weekend, according to the National Weather Service.

Weather Service meteorologist Ian Morrison said this winter promises to be a wet one.

"We’re getting into the winter … rainy season," Morrison said.

The atmosphere will become more stable early next week as the trough aloft moves away to the northeast, the weather service said. 

A high building northeast of the area will bring light tradewinds Monday.

In Hawaii County, a flood advisory was issued for Keauhou, Kealakekua, Holualoa and Captain Cook, with heavy rain near Milolii, about 29 miles south of Kailua-Kona.

Weather officials today were warning Hawaii island people not to cross fast flowing or rising water in motor vehicles and to avoid camping or hiking near streams and low-lying areas.