MIAMI, Oct 14 (Reuters) - The ninth tropical storm of the Atlantic hurricane season became a weak hurricane early on Thursday, threatening Havana and western Cuba and dousing southern Florida with heavy rains as it headed north.
Thousands of people were being evacuated from coastal areas in Cuba as Irene's winds and rains lashed the country and emergency workers were on maximum alert, officials said in the Caribbean nation, 90 miles (145 km) from Florida across the Florida Straits.
Tropical storm watches, indicating the arrival of storm conditions within 36 hours, were issued for lower and middle Florida.
The U.S. National Hurricane Centre said a more urgent hurricane or tropical storm warning might be required later Thursday morning, although Irene, with winds of minimal hurricane strength of 75 mph (120 kph) was not expected to become much stronger before making landfall.
''We're not expecting it to be over warm water long enough for it to do more than become a low Category Two,'' hurricane centre Trisha Wallace said, referring to the five-category Saffir-Simpson scale of storm strength that forecasters use.
''Major'' hurricanes with winds capable of severe damage to buildings are Category Three and higher.
Forecasters said a hurricane watch, indicating that winds of at least 74 mph (119 kph) and heavy rains would arrive within 36 hours, might be required for part of Florida's southwest coast sometime during the day.
''Right now the three-day forecast is taking it along the Florida coast, in central Florida, near Tampa, on Sunday, but that is a long-range forecast,'' Wallace said.
Emergency workers prepared to open shelters in the Florida Keys. Tourists were asked to leave the low-lying chain of islands at the state's southern tip, but authorities said they did not anticipate any mandatory evacuations.
At 8 a.m. EDT (1200 GMT), the National Hurricane Centre reported that Hurricane Irene was about 125 miles (201 kms) south-southwest of Havana, near latitude 21.6 north and longitude 83.5 west.
It had moved little over the last few hours but was expected to resume a slow northward track near 7 mph (11 kph) later in the day, which would take it over western Cuba sometime during the day.
Hurricane force winds extended 15 miles (24 km) and tropical storm winds of 39 mph (63 kph) or higher extended 115 miles (185 km) from Irene's centre.
Rains of from 6 to 12 inches (15 cm to 30 cm) were forecast for its path.
A hurricane warning issued on Wednesday remained in effect for western Cuba including the provinces of Pinar Del Rio, Havana, Ciudad Havana, Matanzas and the Isle of Youth.
A hurricane watch was issued for the lower and middle Florida Keys west of Craig Key, and for the Dry Tortugas.
Squalls and gusty winds had spread over the Cayman Islands, a three-island British territory south of Cuba, but a tropical storm warning was lifted for the Caymans on Thursday morning, forecasters said.
- Reuters - Thomson Reuters Foundation
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