Hurricane Lester and Tropical Storm Madeline both picked up strength in the Pacific on Saturday, the US National Hurricane Center said, with both possibly heading towards Hawaii.

The center of Lester -- which became a hurricane late Friday -- was located some 595 miles (960 kilometers) southwest of the southern tip of Baja California, the NHC said in its 0900 GMT bulletin.

Lester is packing maximum sustained winds of 85 miles (140 kilometers) per hour, but there are no coastal watches or warnings because it is moving west into the Pacific at a speed of 12 miles (19 kilometers) per hour.

"This motion is expected to continue with an increase in forward speed during the next couple of days," the Miami-based NHC said.

Lester's hurricane-force winds extend up to 25 miles (35 kilometers) from its center, and tropical-force winds extend outward up to 90 miles (150 kilometers).

Late Friday the Hurricane Center announced the formation of Tropical Storm Madeline, also in the Pacific -- a storm that could become a hurricane and strike Hawaii.

At 0900 Saturday, Madeline's center was located about 1,160 miles (1,865 kilometers) east-southeast of Hilo, Hawaii, and moving towards the west-northwest at a speed of 10 miles (17 kilometers) per hour.

The storm currently packs maximum sustained winds of 50 miles (85 kilometers) per hour, but could gain strength and become a hurricane by late Sunday or Monday.

- Target Hawaii? -

According to the NHC's five-day forecast cone, Madeline's center could reach just north the Island of Hawaii -- the largest island in the archipelago -- by late Wednesday.

And on its current path Hurricane Lester is also heading towards the Hawaii Islands.

The temperature of the ocean in that part of the Pacific is warm enough to sustain these kinds of storms, said Norman Hui at the National Weather Service forecast office in Honolulu, Hawaii.

Madeline is forecast to come "very close to the island of Hawaii," Hui told AFP.

And if Lester "continues on its current path it might reach Hawaii," he said.

Storm forecasts are usually accurate for the first 48 hours, but there is greater uncertainty after the third day.

Lester, for example, would not reach Hawaii until the end of next week, and it "will probably change course" before that, Hui said.