Heavy rains over the leeward areas of most of the main Hawaiian Islands will most likely continue until temperatures drop later in the afternoon, a National Weather Service forecaster said.

"It's a little bit unusual for this time of year," said Robert Ballard, lead forecaster. "It's just a combination of the light trade winds and the daytime heating. It's happening on most of leeward sides of the islands, but it will settle down when we lose the heat."

A flood advisory was issued by the National Weather Service until 3:15 p.m. for southwestern O'ahu because of isolated showers that developed over the Wai'anae slopes and portions of Leeward O'ahu, just west of Kapolei.

The isolated showers — heavy downpours — are mostly stationary, slowly drifting west and aren't expected to reach east to Honolulu.

Ballard said a rain gauge in Lualualei recorded a 1/2-inch of rain over a two-hour time period this afternoon and 1/4-inch of rain was recorded at Poamoho in 15 minutes.

"Makakilo looks like it got the brunt of it with 1 to 2 inches," Ballard said.

The National Weather Service is urging people to stay away from streams, drainage ditches and low-lying areas. There is a potential for ponding from the rainfall and runoff, which could also cause hazardous driving conditions. Visibility is also reduced and the wet weather could affect braking.

The advisory may be extended if rains persist.