* Makes landfall southwest of Santiago de Cuba
* Extensive coastal flooding reported
* At least 55,000 people evacuated ahead of storm
* Weather station above city reports 152 mph (245 kph) gusts
* Hurricane warning for Bahamas, Florida storm warning extended
HAVANA, Oct 25 (Reuters) - Hurricane Sandy, strengthening rapidly after crossing the warm Caribbean Sea, slammed into southeastern Cuba early on Thursday with 105 mph winds that cut power and blew over trees across the city of Santiago de Cuba.
A Cuban television reporter, reporting by telephone from the communist island's second largest city, held the phone up to a window so viewers could hear Sandy's roaring winds that he said had left the city ``completely dark'' and created a ``very tense'' situation.
He said the Category 2 storm had toppled many trees across the city of 500,000 people situated some 470 miles (750 km) southeast of the capital Havana.
The National Hurricane Center said in Miami at 5 a.m. EDT (0900 GMT), Sandy, with maximum sustained winds of 105 mph, was preparing to move off Cuba's northeastern coast.
The eye of the storm came ashore just west of the city with waves up to 29 feet (9 meters) and a six-foot (2 meter) storm surge that caused extensive coastal flooding, Jose Rubiera of the Cuban weather service said in a television report.
Heavy rains were falling throughout the storm-stricken region, with forecasters predicting 6 to 12 inches for most areas and as much as 20 inches (50 cm) in isolated places.
Rubiera said Sandy had intensified rapidly as it neared land fueled by 88 degree (31 Celsius) waters on its way from Jamaica, struck earlier in the day by the storm when it was still at Category 1 on the five-step Saffir-Simpson hurricane intensity scale.
A Category 2 storm has winds between 96 and 110 mph (154 and 177 kph), leaving Sandy within a whisker of becoming a Category 3 hurricane.
Rubiera said a weather station on the Gran Piedra, a mountainous outcropping near Santiago de Cuba, had had gusts up to 152 mph (245 kph).
At least 55,000 people had been evacuated ahead of Sandy, Cuban officials said, principally because of expected flooding.
HEADED FOR BAHAMAS
Forecaster said the storm, moving north at 18 mph (30 kph), would cross the island within a few hours, heading toward the Bahamas, where hurricane warnings have been posted for the southeastern Ragged Islands, the central Bahamas and the northwestern Bahamas.
A tropical storm warning along the Florida east coast has been extended northward to Flagler Beach and a tropical storm watch has been issued for the northeastern Florida coast from Fernandina beach southward to north of Flagler Beach.
The storm would maintain much of its intensity as it marches across Cuba, the hurricane center said.
``After a slight jog to the north-northeast very early this morning ... Sandy appears to have resumed a northward motion ... and this general motion is expected to continue for the next 24 hours or so,'' it said.
Sandy was not expected to enter the Gulf of Mexico, where the United States has extensive oil and gas installations.
The Cuban government suspended flights to and from eastern Cuba, along with bus and train services in the area. Nearly 1,000 tourists were taking shelter in their hotels, officials said.
Officials put agricultural products including sugar and coffee into warehouses out of harm's way. Almost 3,000 Cubans working on the coffee harvest in Santiago de Cuba were sent home.
In Holguin province, processing plants for Cuba's main export nickel continued operations, Cuban television said.
Cubans battened down the hatches as the storm approached.
``The weather is getting very ugly,'' said 45-year-old self-employed worker Esteban O'Reilly in Santiago de Cuba.
``I've lit a candle to the Virgin of Charity, the patron saint of Cuba, to ask that Sandy not do much damage.''
Student Elizabeth Cusido, 23, said the storm was more than she could bear.
``The only thing I can do is close my eyes and hope that nothing happens,'' she told Reuters. ``I have tremendous fear of the winds and floods.''
At the Guantanamo Bay U.S. Naval Base, electricity was out and all but emergency workers were confined to quarters, said a Reuters reporter at the base to cover war crimes tribunals.
In Jamaica, Sandy earlier caused widespread power outages, flooded streets, damaged homes and led to at least one death. The hurricane warning for Jamaica has been discontinued.
A police official said a man died under a crush of stones that fell from a hillside as he tried to get into his house in a rural village near Kingston, Jamaica's capital.
Computer models generally forecast that Sandy would steer clear of the U.S. East Coast, but some showed it could pose a risk to the U.S. Northeast early next week.