By David Adams
MIAMI (Reuters) - Tropical Storm Erika threatened Haiti and the Dominican Republic with heavy rain and strong winds on Friday as it swirled across the Caribbean and geared up for a run at south Florida, the U.S. National Hurricane Center said.
At least 12 people were confirmed dead on the island of Dominica, Prime Minister Roosevelt Skerrit said on Twitter, adding: "The number may be higher."
Due to some likely weakening over mountainous areas, Erika was no longer forecast to make landfall in the United States as a hurricane. But it may still smack the Miami area by late Sunday with sustained winds of 60 miles per hour (97 kph), before sweeping northward up the Florida peninsula, toward Orlando's popular theme parks.
Florida Governor Rick Scott declared a state of emergency on Friday, noting the storm could travel "up the spine of Florida" from Sunday into next week.
Scott said the Tampa area on Florida's Gulf Coast was a major flood concern due to saturation from rain earlier this month.
He urged residents, especially those who have moved to Florida in the decade since Hurricane Wilma - the last major storm to hit the state, in 2005 - to follow news reports and make possible evacuation plans.
U.S. President Barack Obama has asked for regular updates on the forecast for Erika over the weekend, White House spokesman, Josh Earnest said.
The storm also caused cruise lines to adjust itineraries for some ships coming in and out of South Florida, rerouting to avoid the storm.
The greatest risk over the next few days is heavy rainfall over the Dominican Republic and impoverished Haiti's notoriously eroded hillsides, with up to 10 inches (25 cm) possible in some areas. This could cause "life-threatening flash floods and mud slides," the Miami-based NHC said.
Dominica's prime minister said in a radio broadcast that emergency officials were searching for several missing people after rain-triggered landslides on Thursday on the small, mountainous island with a population of about 72,000.
Overflowing rivers and landslides washed away several roads and bridges there, and the nation's Tourism Minister Robert Tonge posted photographs and video on Facebook showing widespread flooding in the capital.
For days, forecasters have described Erika, the fifth named storm of the Atlantic hurricane season, as unusually hard to predict due to disruption from wind patterns and its interaction over land, which weakens a storm, as well as warm water, which adds energy.
As Erika neared the Dominican Republic's capital, Santo Domingo, on Friday, its sustained winds were measured at 50 mph, the NHC said.
The storm should weaken as it passes over the mountains of the Dominican Republic and Haiti, "and could degenerate to a tropical wave," the center said.
If Erika survives the mountains, it would probably regain intensity over warm seas in the Bahamas and the Straits of Florida, it added.
(Additonal reporting by Bill Cotterell in Tallahassee and Roberta Rampton in Washington; editing by Lisa Von Ahn, Louise Ireland and G Crosse)