Tropical Storm Erick likely to grow into hurricane en route toward Hawaii

July 29 (Reuters) - Tropical Storm Erick in the eastern Pacific is likely to grow into a hurricane soon, possibly reaching Category 3 strength by Tuesday as it churns closer toward Hawaii, but it is expected to begin weakening later in the week, forecasters said on Monday.

The latest advisory from the U.S. National Hurricane Center put Erick's center at about 1,200 miles (1,945 km) east-southeast of Hawaii's Big Island, the easternmost edge of the U.S. archipelago state, still too far away to pose any threat to land.

Packing maximum sustained winds near 70 miles per hour (110 kph), Erick was poised to reach hurricane strength imminently, and could grow by Tuesday into a major hurricane, defined as a Category 3 on the five-step Saffir-Simpson wind scale, according to the latest forecast.

Erick would be the third hurricane in the eastern Pacific this season.

"A weakening trend is expected to begin later in the week," the hurricane center advisory said.

A tropical storm becomes classified as a Category 1 hurricane when its top sustained winds reach 74 mph (119 kph). Sustained wind speeds of at least 111 mph (178 kph) make it a Category 3.

The weather system is expected to weaken back into a tropical storm by the time it makes its closest approach to Hawaii, with Erick forecast to skirt south of the Big Island on Friday morning. Forecasts call for a higher chance of gale-force winds from the storm on the Big Island later this week.

Another tropical storm, dubbed Flossie, was trailing Erick farther out in the eastern Pacific. (Reporting by Steve Gorman in Los Angeles; Editing by Sandra Maler)