Melissa becomes a hurricane and advances with force; Jamaica prepares for its arrival.

Tropical Storm Melissa has strengthened into a hurricane and is expected to reach at least Category 4 strength, the U.S. National Hurricane Center (NHC) reported Saturday.

The rapidly intensifying storm is expected to wreak havoc across the Caribbean, with catastrophic flooding, mudslides, and storm surges expected in Jamaica and southern Hispaniola through early next week, forcing authorities and residents to prepare.

Hurricane Melissa is located about 210 kilometers southeast of Kingston and about 400 kilometers southwest of Port-au-Prince, Haiti, the NHC said in its latest advisory.

Maximum sustained winds increased to near 150 kilometers per hour.

"I urge all my fellow citizens to be prepared," Jamaican Prime Minister Andrew Holness said during a press conference in Kingston, adding that "all of Jamaica will be affected" for several days.

Holness advised residents of low-lying areas like Port Royal in Kingston to evacuate, but did not issue a mandatory order.

Evan Thompson, senior director of the Jamaica Meteorological Service, said Melissa is expected to make landfall in Jamaica as a Category 4 storm on Tuesday and remain for five days. Category 4 hurricanes have sustained winds of 209 to 241 kilometers per hour.

"Today is really the last day to do what needs to be done outside," Thompson said.

The people of Jamaica rushed to secure supplies and protect their homes, while fishermen and vendors in Kingston raced to prepare their boats and sell their wares before the storm hit.

"When it moves slowly, it's the worst, because no one knows what's coming next," said Diane Thompson, a local herb vendor. "This morning I asked God to see if He can turn the storm back. Because no matter what happens, we can't control it."

The NHC said the storm is currently moving west at 6 kilometers per hour (3.7 mph) and is forecasting 15 to 30 inches (38 to 76 centimeters) of rain in Jamaica and southern Hispaniola, with a possible local maximum of 40 inches (101 centimeters).

Eastern Cuba is expected to receive 15 to 30 centimeters, with 45 centimeters in some places.

Storm surges of up to 3.96 meters (12.5 feet) are expected along Jamaica's southern coast, accompanied by large and destructive waves.

Major storm surges are expected off Cuba's southeastern coast early next week, the agency added.