Caribbean residents are preparing for a weekend of heavy rain and flooding as powerful Hurricane Matthew barrels toward Jamaica, Haiti and eventually Cuba. For several hours overnight Matthew became a Category 5 storm — the strongest on the 1-5 Saffir-Simpson scale, and the most powerful Caribbean storm since Hurricane Felix in 2007. By early Saturday Matthew had weakened into a still dangerous Category 4 hurricane, the Miami-based National Hurricane Center said in its 0900 GMT bulletin. The storm was swirling off the northern coast of Colombia and Venezuela packing winds of 155 miles (250 km) per hour, with higher gusts. The center of Matthew was located 365 miles south of the Haitian capital Port-au-Prince, and 420 miles southeast of Kingston, Jamaica, the NHC said. The storm is currently moving toward the west at seven miles per hour, but is expected to turn toward the northwest on Saturday. Matthew became a Category 1 hurricane on Thursday afternoon, then swiftly rose to Category 4 a day later. Late Friday it strengthened into a powerful Category 5 storm. The NHC's long-term forecast has Matthew hitting the southern coast of Cuba late Monday or early Tuesday after tearing across Jamaica. As for threats to US soil, "it is too soon to rule out possible hurricane impacts from Matthew in Florida," the NHC said. Hurricane Felix killed some 150 people and left thousands homeless when it slammed the Caribbean coast of Nicaragua in September 2007. Residents in Jamaica and southern Haiti scrambled to prepare as the storm headed in their direction. Forecasters said that 10-15 inches (25-38 centimeters) of rain could fall across the region. In Haiti, authorities warned residents of the country's southern islands that they were "first at risk," and urged them to prepare. "We invite them to secure the area surrounding their homes and begin to stock up on water and food," Edgar Celestin, a spokesman for the Haitian civil protection agency, said. In Jamaica, Local Government Minister Desmond McKenzie told The Star newspaper that Prime Minister Andrew Holness had instructed authorities to "go full speed ahead" with efforts to prepare for and respond to the hurricane. That includes placing some 2,000 homeless people in shelters, McKenzie told the newspaper. Separately, the US embassy in Jamaica said it will be closed Monday and Tuesday for consular services "due to the anticipated effects of Hurricane Matthew." Heavy rain from Matthew "may produce life-threatening flash flooding and mud slides" in the affected area, the NHC warned, saying isolated areas could be lashed with up to 25 inches of rain. Ocean swells with the potential to cause dangerous currents and rip tides are also possible over the next two days in coastal regions of Puerto Rico, Venezuela, Aruba, Bonaire, Curacao, Colombia, the Dominican Republic and Haiti. Colombia issued a high-level alert for much of its northern coast, warning of "extremely dangerous life-threatening conditions" and of giant waves up to five meters high. The Atlantic hurricane season normally runs from June 1 to November 30, but this year's first hurricane, Alex, formed in January.