MIAMI, Florida (AP) -- Tropical Storm Stan made landfall in Mexico's Yucatan Peninsula early Sunday with 45 mph sustained winds, but forecasters predicted it would weaken to a tropical depression as it moves over the region.

A tropical storm warning was in effect for the eastern coast of the Yucatan from Chetumal north to Cabo Catoche, forecasters said.

At 5 a.m. EDT, the center of the storm was about 40 miles south of Tulum, Mexico, and about 75 miles south-southwest of Cozumel, the National Hurricane Center in Miami said.

Stan, the 18th named storm of the Atlantic hurricane season, was moving to the west-northwest near 6 mph.

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

Forecasters predicted the storm could restrengthen to a tropical storm after moving over the Yucatan region and re-entering the warm waters of the Gulf of Mexico on Monday.

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

At 5 a.m., the depression was about 715 miles west of the Cape Verde Islands and was moving toward the north-northwest near 8 mph. Maximum sustained winds were near 35 mph.

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 November 30.