* Sandy expected to blanket eastern third of U.S.
* Widespread flooding and power outages feared
* Similar to ``Perfect Storm'' that formed in 1991
* Storm already affecting presidential campaigning
(Recasts, new throughout, changes dateline From Nassau)
MIAMI, Oct 26 (Reuters) - Hurricane Sandy, a late-season Atlantic cyclone that threatens to be one of the worst storms to hit the U.S. Northeast in decades, slogged slowly northward on Friday after killing at least 41 people in the Caribbean.
Forecasters said wind damage, widespread and extended power outages and coastal and inland flooding were anticipated across a broad swath of the densely populated U.S. East Coast when Sandy comes ashore early next week.
``We're expecting a large, large storm. The circulation of this storm as it approaches the coast could cover about the eastern third of the United States,'' said Louis Uccellini, director of the National Oceanic and Atmospheric Administration's Centers for Environmental Prediction.
He stopped short of calling Sandy possibly the worst storm to hit the U.S. Northeast in 100 years, as some weather watchers were doing, but said Sandy was shaping up to go down as a storm of ``historic'' proportions.
The late-season hybrid storm has been dubbed ``Frankenstorm'' by some weather watchers because it will combine elements of a tropical cyclone and a winter storm. Forecast models show it will have all of the ingredients to morph into a massive and potentially catastrophic ``super storm.''
On its current projected track, government forecasters said, Sandy could make landfall on Monday night or Tuesday in Maryland, Delaware, New Jersey, New York or southern New England.
In New York City, the global financial hub, officials were considering closing down mass transit before the storm hits.
ROMNEY, BIDEN CANCEL TRIPS
Coming in the final weeks before the U.S. presidential election on Nov. 6, the storm could throw last-minute campaign travel plans into chaos.
An aide to Republican presidential challenger Mitt Romney said he had canceled a campaign event scheduled for Sunday night in Virginia Beach, Virginia. President Barack Obama's re-election campaign announced that Vice President Joe Biden had also canceled a trip to Virginia Beach scheduled for Saturday.
The Democratic incumbent was traveling to New Hampshire on Saturday, and on Monday was due to visit Youngstown, Ohio, and Orlando, Florida.
Craig Fugate, director of the Federal Emergency Management Agency, said he and the head of the U.S. National Hurricane Center had briefed the president on preparations for the storm on Friday morning.
``His direction to us again, as always, is to make sure we are prepared to support the states and the governors dependent upon the impacts of the storm,'' Fugate told reporters.
Much of Florida's northeast coast was under a tropical storm warning on Friday, and storm watches extended up the coast through North Carolina. Winds and rains generated by Sandy were being felt across much of Florida, with schools closed and air travel snarled in many areas.
Sandy weakened to a Category 1 storm as it tore though sparsely populated low-lying southeastern islands in the Bahamas late Thursday, knocking out power and blowing rooftops off some homes.
Some further weakening was forecast over the next two days, but the Miami-based National Hurricane Center said hurricane- or tropical-force winds were still likely by the time Sandy hits the U.S. coast.
Sandy's driving rains and heavy winds were blamed for 41 deaths in the Caribbean, where landslides and flash floods were triggered by the cyclone.
The Cuban government said Sandy killed 11 people when it tore across the island on Thursday. The storm took at least 26 other lives in deeply impoverished Haiti and four people were killed in the Dominican Republic, Jamaica and the Bahamas.
The Haitian dead included a family of five in Grand-Goave, west of the capital Port-au-Prince, killed in a landslide that destroyed their home, authorities said.
The Cuban fatalities were unusual for the communist-ruled country that has long prided itself on protecting its people from storms by ordering mass evacuations.
The National Hurricane Center said Sandy was about 420 miles (670 km) south-southeast of Charleston, South Carolina, late on Friday afternoon, packing top sustained winds of 75 miles per hour (120 km per hour).
Sandy was forecast to remain a Category 1 hurricane as it completed it passage over the Bahamas late on Friday, sending swirling rains and winds across areas including Florida.
It was moving slowly, however, making its final trek across the central and northwest corner of the Bahamas islands at 7 mph (11 kph).
Many forecasters are warning that Sandy could be more destructive than last year's Hurricane Irene, which caused billions of dollars in damage as it battered the U.S. Northeast.
Uccellini said he was reluctant to make comparisons with other storms. But he warned that a full moon on Sunday added to Sandy's potential for destruction when it comes ashore in the United States.
``The lunar tide peaks two days after the full moon, and that's Monday-Tuesday, which is exactly when the storm will be impacting the coastal areas,'' he said. ``We'll have heavy rains and inland river flooding is a real potential here.''
Todd Kimberlain said Sandy was somewhat unique because of its integration with the polar trough over the United States.
``We went through this same sort of thing back about 20 years ago around Halloween in 1991 with the 'Perfect Storm,''' Kimberlain said.
That storm, featured in a book and movie of that name, combined several different storm systems to ravage the East Coast.
A forecast report on Friday from AccuWeather.com predicted ``a catastrophic storm'' for the Middle Atlantic and Northeast.
``It will not be a purely tropical system, with a core of powerful winds near the center, but rather more like a Nor'Easter, with strong winds over a larger area,'' the report said.
(Additional reporting by Jeff Franks and Nelson Acosta in Havana, Kevin Gray in Miami, Susana Ferreira in Port-au-Prince and Gene Cherry on Hatteras Island, North Carolina; Writing by Tom Brown; Editing by Vicki Allen and Mohammad Zargham)