The Dominican Republic has issued a hurricane alert as a tropical storm closes in on its southern coast. Forecasters at the National Hurricane Center in Miami said tropical storm Irene could turn into a hurricane before making landfall. They expect it to pass near Puerto Rico and make landfall in the Dominican Republic on Monday. Haiti, where hundreds of thousands of people still live in tents after last year’s earthquake, could also be hit. The National Hurricane Center said the storm was over western Guadeloupe heading west north-west at 17mph (27kmh). The forecasters said Irene had maximum sustained winds of 50mph (80kmh). Sustained winds have to reach 74mph (119kmh) before Irene can be classified as a hurricane. Haiti, which suffers from extensive deforestation and poor infrastructure, is particularly vulnerable to the heavy rains Irene is expected to dump.