Tropical Storm Ernesto drenched southeastern Cuba on Monday as it stayed on a path toward the Florida Straits, where it could regain its hurricane strength and then hit the densely populated Miami-Fort Lauderdale area, Reuters reported. The U.S. National Hurricane Center said Ernesto's winds dropped to 40 mph (65 kph) as it moved inland in eastern Cuba, but said heavy rains could cause life-threatening flash floods and mud slides. The storm, which had become the year's first hurricane on Sunday, could become a hurricane again over the Florida Straits with winds of about 86 mph (137 kph) as it approaches Florida's southern coast, the center warned. "Ernesto is but a shadow of its former self," said Cuban weather forecaster Jose Rubiera, who predicted the storm will weaken further as it passes over mountainous terrain. More than 3 inches (7.5 cm) of rain fell in four hours on the hills above Guantanamo, Cuba's eastern-most city. By mid-morning the downpour was over. "It has stopped raining. People are shopping. The worst is over," said Communist Party official Nelson Maso in Caimanera, bordering the U.S. naval base in Guantanamo Bay. Ernesto's center was 35 miles (55 km) west-northwest of Guantanamo at 11 a.m. EDT (1500 GMT), and moving northwest at about 10 mph (17 kph), the Miami-based hurricane center said. Ernesto will possibly emerge off the northern coast of Cuba on Monday night, it added. "How long the center spends over Cuba is going to determine how strong the system emerges north of Cuba," hurricane specialist Rick Knabb told reporters in Miami. "Right now we think there is a decent chance that the system will spend a short enough time over Cuba such that it will have an opportunity to strengthen (before reaching Florida)." Florida, storm-weary after being hit by eight hurricanes in the past two years, prepared for the worst. The state government declared a state of emergency and tourists were ordered out of the vulnerable Florida Keys almost a year to the day since Hurricane Katrina swamped New Orleans. Schools were closed on the Keys, a low-lying, 110-mile (177-km) island chain off Florida's southern tip. A hurricane watch was extended along Florida's east coast to New Smyrna Beach and for Lake Okeechobee, and was in effect along the west coast from south of Chokoloskee. The Bahamas issued a hurricane watch for Bimini Islands and Grand Bahama Island. A hurricane watch means hurricane conditions are possible within 36 hours. "My suggestion is to take this storm very seriously," Florida Gov. Jeb Bush said. "A hurricane is a hurricane." NASA on Monday called off the launch of the space shuttle Atlantis this week because of Ernesto. The spacecraft will most likely be taken off the launch pad at Cape Canaveral on the Atlantic coast to keep it safe. Ernesto was downgraded to a tropical storm after skirting southern Haiti, pounding the poorest country in the Americas with flooding rain and killing at least one person there. There was an unconfirmed report of another death in the Haitian port city of Gonaives, where tropical storm flooding killed 3,000 people two years ago. Cuba, facing its first big storm in decades without its ailing leader, Fidel Castro, at the helm, evacuated more than 600,000 people from eastern provinces. Tens of thousands of Cubans were transported from coastal and mountain areas in buses and trucks. Cattle and crops were protected and domestic flights to eastern Cuba suspended. There was no sign of Raul Castro, the younger brother who took over Cuba's government while Fidel Castro recovers from intestinal surgery. New Orleans breathed easier as Ernesto aimed away from the historic jazz city. Katrina struck New Orleans last Aug. 29, killing about 1,500 people on the Gulf Coast and causing more than $80 billion in damage. Oil prices fell over $1 on Monday after Ernesto seemed less likely to threaten oil facilities in the Gulf of Mexico, where a quarter of U.S. oil and gas is pumped.