Hurricane Melissa has strengthened into a major Category 4 hurricane as it inches closer towards Jamaica. The US National Hurricane Center has warned of catastrophic flash flooding and landslides across portions of southern Hispaniola and Jamaica, with torrential rains of up to 760 millimetres expected. People on the island are being urged to seek shelter immediately, with the possibility of Melissa intensifying to a Category 5 storm on Sunday night, and likely to reach the southern coast of Jam