Haitians living in makeshift tent camps are bracing for possible life-threatening flash floods and mudslides as a result of Tropical Storm Emily.

Some rain is already falling on southern Haiti, but forecasters say the brunt of the storm is not expected to hit until later in the day. At last report , the storm was 90 kilometers southwest of Isla Beata, Dominican Republic, moving northwest at about seven kilometers an hour.

Forecasters say the storm could drop as much as 50 centimeters of rain on Haiti and the Dominican Republic, possibly causing flash flooding and mudslides.

In Haiti's capital of Port-au-Prince, hundreds of thousands of people are still living in tent cities after a devastating earthquake last year that left the city in ruins. Officials are urging people to seek shelter elsewhere if they can. No official evacuation has taken place.

Forecasters predict Emily will move on to eastern Cuba late Thursday or early Friday.

Haiti's tent cities perched on hillsides are particularly at risk, because much of the landscape has been stripped bare of trees, which have been cut down for use as fuel or building materials. A slow-moving storm in June caused mudslides and flooding that killed at least 28 people.

The U.S. National Weather Service said Thursday that the rest of the Atlantic hurricane season is expected to be unusually active, with three to five storms expected to become major hurricanes.

Hurricane season in the Atlantic spans from June 1 to November 30.