The Saturday morning tropical storm Fiona update from he NHC forecast shows Fiona strengthening into a hurricane on Sunday. Fiona continues to swirl through the Caribbean this morning as a strong tropical storm. Heavy rains and tropical storm force winds are expected to continue across the northern Leeward Islands today. Later this afternoon, tropical storm conditions will reach Puerto Rico. The latest forecast trend from the NHC shows Fiona strengthening into a hurricane as early as Sunday afternoon as it brushes eastern Dominican Republic.