KINGSTON, Jamaica — Heavy floodwaters swept across southwestern Jamaica , winds tore roofs off buildings and boulders tumbled into roads Tuesday as Hurricane Melissa came ashore as a catastrophic Category 5 storm, one of the strongest Atlantic hurricanes on record. Desmond McKenzie, deputy chairman of Jamaica’s Disaster Risk Management Council, urged people to seek shelter and stay indoors as the storm crosses the island. “ Jamaica , this is not the time to be brave,” he said. The Jamaican