UPDATE 2-'Super storm' Sandy heads toward U.S. northeast coast

* Storm downgraded from hurricane status

* Has potential to blanket eastern third of U.S.

* It killed at least 41 across the Caribbean

MIAMI, Oct 27 (Reuters) - Hurricane Sandy was downgraded on Saturday morning but remained highly menacing as it pulled away from the Bahamas, making a slow path toward the U.S. northeast coast where it threatens to become one of the worst storms in decades.

The late-season storm has been dubbed ``Frankenstorm'' by some weather watchers because it will combine elements of a tropical cyclone and a winter storm and is forecast to reach the U.S. coast close to Halloween.

Forecast models show it will have all the ingredients to morph into a so-called ``super storm'', stirring memories of the 1993 'Storm of the Century', whose impact in the United States was particularly destructive.

Governors in states along the U.S. East Coast declared emergencies on Friday, with officials urging residents to stock up on food, water and batteries.

The U.S. Navy ordered all ships in the Norfolk, Virginia, area, including a nuclear-powered aircraft carrier, out to sea to ride out the approaching storm.

``We're expecting a large, large storm,'' said Louis Uccellini, director of the National Oceanic and Atmospheric Administration's Center for Environmental Prediction. ``The circulation of this storm as it approaches the coast could cover about the eastern third of the United States.''

Sandy battered the Bahamas southeast of Florida on Friday after causing widespread destruction in eastern Cuba a day earlier. Th e storm was expected to crawl northward on Saturday and Sunday and then turn toward the U.S. coast.

On its current projected track, Sandy could make landfall on Monday night or Tuesday somewhere between North Carolina and southern New England, forecasters said.

The storm has the potential to cause widespread power outages and to unleash flooding and even dump snow as far inland as Ohio. It also threatens to disrupt air travel along the U.S. East Coast.

Early Saturday morning, Sandy was about 350 miles (565 km) southeast of Charleston, South Carolina, packing sustained winds of 70 miles per hour (110 km per hour), just below hurricane strength according to the Saffir-Simpson scale of storm intensity.

It had picked up a little speed overnight but was still moving slowly over the Atlantic at 10 mph (17 kph), the U.S. National Hurricane Center said.

PRESIDENTIAL ELECTION

Sandy was forecast to speed up over the weekend as it moved parallel to the U.S. coast, possibly strengthening into a Category 1 hurricane again on Sunday.

Despite being downgraded, the storm continued to grow in size with tropical force winds extending 450 (725 km) from its center, forecasters said.

Coming in the final weeks before the U.S. presidential election on Nov. 6, the storm was presenting a challenge to the campaigns of U.S. President Barack Obama and his Republican challenger Mitt Romney.

Romney canceled a rally scheduled for Sunday evening in Virginia Beach, Virginia, while President Obama's re-election campaign announced that Vice President Joe Biden had also canceled a Saturday trip to Virginia Beach.

Ahead of the election, millions of Americans are taking advantage of early voting arrangements to cast their ballots. State officials said they had put in place contingency plans in case Sandy caused extended power outages or other problems that could disrupt voting.

In New York City, officials were considering shutting down the country's largest mass transit system because they were worried the storm's impact could cause flooding or high winds that might endanger subways and buses.

Much of Florida's northeast coast was under a tropical storm warning and storm watches extended up the coast through South Carolina.

Along North Carolina's Outer Banks, which jut out into the Atlantic, vacationers in large camper trailers and motor homes streamed off the barrier islands.

Many forecasters are warning that Sandy could be more destructive than last year's Hurricane Irene, which caused billions of dollars in damage across the U.S. Northeast.

Sandy's powerful winds and rains were blamed for 41 deaths in several Caribbean countries, including 11 in Cuba. Most were killed by falling trees and building collapses.

In eastern Cuba, the authorities continued clearing streets in the historic city of Santiago which was struck on Thursday by 110-mile-per-hour (177 kph) winds.