Updated

The hurricane season's 20th tropical depression formed in the western Caribbean Sea on Saturday, prompting the Mexican government to issue tropical storm warnings for the Yucatan Peninsula (search), forecasters said.

At 11 a.m. EDT, the depression was located about 125 miles east-southeast of Tulum, Mexico, and about 110 miles southeast of Cozumel, the National Hurricane Center (search) in Miami said. The system had sustained winds of 30 mph, and was moving to the west-northwest near 6 mph.

The storm could become a named tropical storm, with winds above 39 mph, before it makes its expected landfall on the eastern Yucatan later Saturday or Sunday.

Rainfall accumulations from 5 to 10 inches over the Yucatan and northern Belize were expected, forecasters said.

A tropical storm warning was issued in the Yucatan from Punta Gruesa north to Cabo Catoche, while a tropical storm watch was issued from Cabo Catoche west to Campeche. A warning means that storm conditions were expected within 24 hours, while a watch means they are expected within 36 hours.

Meanwhile, tropical depression 19 remained no threat to land as it organized far out in the Atlantic.

At 11 a.m., the depression was about 665 miles west of the Cape Verde Islands and was moving toward the north-northwest near 7 mph. Maximum sustained winds were near 35 mph, and the depression could become a tropical storm later Saturday or Sunday.

Either depression would be named Tropical Storm Stan (search) if it strengthens into the 18th named system of the season. The 19th named storm of the season would be named Tammy.

This is the fourth-busiest Atlantic hurricane season since record-keeping started in 1851. The record for tropical storms in one year is 21, set in 1933. The hurricane season ends Nov. 30.