Tropical storm Isaac threatens Haiti with up to 12 inches of rain – CNN's Gary Tuchman reports from Port-Au-Prince on the challenge of alerting residents

(CNN) - Tropical Storm Isaac marched toward Haiti on Friday, posing a danger to the nation nearly three years after a devastating earthquake left hundreds of thousands living in camps.

Isaac is expected to whip the Caribbean nation with gale-force winds and stinging rain.

A National Hurricane Center forecast map shows the storm making landfall in the Dominican Republic on Friday morning before churning its way through Haiti over the course of the day. The neighboring nations share the island of Hispaniola.

Hundreds of thousands of Haitians are still living in camps with tents as their only shelters following a magnitude 7.0 earthquake in January 2010.

Isaac was 230 miles southeast of Port-au-Prince, Haiti, early Friday. It had maximum sustained winds of 45 mph, the hurricane center in Miami said, calling the storm "poorly organized."

Rainfall accumulations of 8 to 12 inches are expected, with maximum amounts of 20 inches possible over Hispaniola.

This morning on "Early Start," Gary Tuchmann reports live from Port-Au-Prince with the latest on how Haiti is preparing, and the communication challenges in alerting residents that Isaac is set to hit the island.

READ MORE: Tropical Storm Isaac sets eye on Haiti, Dominican Republic