Tropical Storm Odile may become a hurricane tomorrow as it stays off Mexico’s west coast, while tropical depressions formed in both the Atlantic and Pacific, the U.S. National Hurricane Center said.

Odile, with top winds of 50 miles (80 kilometers) per hour, is in the Pacific 235 miles south of Manzanillo, Mexico, where a tropical storm watch is in effect, the hurricane center said in an advisory at 11 a.m. New York time.

“Additional strengthening is forecast in the next 48 hours and Odile is expected to become ahurricane on Friday,” the Miami-based center said.

Odile is the 15th named storm of the eastern Pacific hurricane season, which ends on Nov. 30. Forecast models show the storm becoming a Category 3 hurricane whose center is expected to remain at sea through the weekend.

A Category 3 storm is considered a major hurricane and is in the center of the five-step Saffir-Simpson scale. Odile’s winds of at least 39 mph now reach 70 miles from its core.

The tropical storm watch extends from Manzanillo to Lazaro Cardenas, Mexico, where high winds and heavy surf and rip currents are possible during the next two days.

Farther west, a tropical depression has developed 775 miles southwest of the southern tip of Baja California, the center said in a special advisory at 11:30 a.m. New York time.

It is may strengthen into Tropical Storm Polo later today. Current forecasts call for it to remain well out to sea and away from land.

In the Atlantic, a tropical depression that may become Tropical Storm Edouard today was 870 miles west of the Cape Verde Islands with top winds of 35 mph. It may become a Category 1 hurricane and isn’t expected to threaten land.

–With assistance from Ann Koh in Singapore and Rupert Rowling in London.