KINGSTON, Jamaica (AP) — Jamaicans on Tuesday braced for sheets of rain, violent winds and a powerful storm surge as strengthening Tropical Storm Sandy churned south of the Caribbean country's southern coast.

The U.S. National Hurricane Center in Miami said Sandy is expected to become a hurricane as it nears Jamaica on Wednesday. The late season storm is expected to travel from south to north over the island.

One weather model shows a slight possibility of Sandy combining with another weather feature to form a major New England storm system early next week.

Early Tuesday, the storm's outer bands were already drenching parts of the Caribbean country with intermittent showers. Skies were largely overcast over Hispaniola, the Caribbean island shared by Haiti and the Dominican Republic.

Jamaica's government issued a hurricane warning on Tuesday morning. It has urged people in flood-prone areas to be on alert and advised fishermen on outlying cays to return to the mainland.

Cuba issued a hurricane watch for the several provinces, including Guantanamo in the extreme east, where authorities at the U.S. military base were trying to condense an agenda for military commission hearings under way there because of Sandy's approach.

Hurricane conditions were possible in eastern Cuba by Wednesday night, according to U.S. forecasters.

Sandy was expected to dump at least 10 inches (25 centimeters) of rainfall in Jamaica, especially over central and eastern parts of the island, according to the country's meteorological service. Flash flooding and landslides are likely, Jamaican forecasters said.

Residents in some low-lying areas of Kingston, Jamaica's capital in the island's south, were bracing for the worst.

"Everybody's worried about it here, I can tell you. This storm is no small thing," said Philip Salmon, a laborer who lives alone in a concrete shack in a shantytown perched along a gully, where impoverished people live illegally due to a lack of affordable housing.

On Tuesday, Salmon and some of his neighbors in the Sandy Park settlement just below the U.S. Embassy were trying to secure more sheet metal to place on their roofs, as well as rocks to hold it down.

Sandy's maximum sustained winds early Tuesday were near 50 mph (85 kph). It was moving north-northeast at about 5 mph (7 kph) and its center was located about 300 miles (480 kilometers) south-southwest of Jamaica late Tuesday morning.

Sandy on Monday became the 18th named storm of this year's busy Atlantic season, which officially ends Nov. 30.

Meanwhile, a tropical depression in the Atlantic was expected to become a tropical storm later Tuesday. It does not pose any threat to land.

The depression's maximum sustained winds are near 35 mph (55 kph). The depression is centered about 915 miles (1,470 kilometers) northeast of the Leeward Islands and is moving north-northeast near 15 mph (24 kph).