National Weather Service forecasters are watching an area of thunderstorms south of the state that could develop into a tropical cyclone and is expected to bring rain to the islands, especially Hawaii island, this weekend.

“Weather conditions may worsen as we head into Saturday night,” the weather service said.

The rains could be heavy over Hawaii island and Maui, with possible thunderstorms Saturday night and Sunday.

Oahu is also expected to get some rains from clouds blown in by the tradewinds.

Satellite images showed high clouds associated with the low-pressure system moving over the Big Island today.

The developing system is about 600 miles south-southeast of Honolulu and has nearly a 100 percent chance of intensifying into a tropical depression. Forecasters were predicting that could occur overnight.

Forecasters expect the current sunny, breezy tradewind weather to continue until Saturday night, when tropical moisture from the system is expected to move over the Big Island.

The wet weather is expected to continue for several days.

“The rest of the forecast will depend on what happens with the tropical cyclone,” forecasters said.

“There’s still a lot of question marks,” said Matt Foster, a meteorologist with the Honolulu office of the National Weather Service.

The system is expected to move northeast and pass east of the Big Island Wednesday night or Thursday. But there are a lot of variables and it’s not clear how strong or what its exact path will be.

“It’s certainly within the realm of possibility that it could hit the Big Island or Maui,” Foster said.

The Central Pacific Hurricane Center is also watching another area of low pressure that has a 70 percent chance of developing into a tropical cyclone over the next two days. That system is about 1,075 miles southwest of Honolulu, but is expected to move away from the islands and should not affect the weather in the main islands.

If either system in the Central Pacific reaches tropical storm strength, it will be given the Hawaiian name of Oho, which means hair of the head, leaves of plants or fronds of ferns, according to the “Hawaiian Dictionary” compiled by Mary Pukui and Samuel Elbert. It also means “to sprout.”

If both systems intensify into tropical storms, the second system to develop will be given the name Pali, which means “cliff.”

In the East Pacific, a low-pressure system about 1,250 miles southwest of Baja California has a 30 percent chance of developing into a tropical cyclone over the next five days. It’s too soon to say if it will have any effect on Hawaii’s weather.

So far this hurricane season, which began June 1 and ends Nov. 30, the Central Pacific has seen a record-tying 11 tropical cyclones. The record was set in 1992 and reached again in 1994.