The National Weather Service has issued a Flood Advisory until 1 a.m. for the south half of Oahu.
Forecasters said at 10 p.m., radar showed heavy rain near Waipahu. Another heavy shower was seen northeast of Pearl Harbor, while another line of showers moved toward the south shore of Oahu east of Pearl Harbor. The showers will produce large amounts of rain individually, and more when they merge.
Persons in the advisory area should avoid streams, drainage ditches and other low-lying areas prone to flooding. The heavy rain may make driving hazardous due to reduced visibility, ponding on the roadway and poor braking.
The advisory may be extended if the heavy rain persists.
Forecasters also warned that a thunderstorm north of Pearl Harbor had intense lightning and the possibility of hail. Do not stay in the open nor seek shelter under trees when lightning threatens. Move indoors when a thunderstorm approaches.
A Flash Flood Watch is also in effect for all Hawaiian islands until 6 p.m. Monday.