The professional women runners in the New York City Marathon began their race Sunday morning, striding across the first steep mile of the 26.2 mile journey over the Verrazano-Narrows Bridge in Staten Island.

The wheelchair and handcycle competitors were already on the road after an earlier start.

Some 50,000 competitors are participating in the 45th running of the marathon, including professional and amateur runners, as well as 330 participants in the wheelchair division and handcycle category.

While there were clouds and sprinkles Sunday morning, forecasters said the weather should get better, with peeks from the sun and highs in the mid-60s.

Temperatures at the start were in the mid-50s and winds were no more than 15 mph, compared to last year's daunting chill and high winds.

About 1 million spectators are expected to come out to cheer on the runners, according to race organizers. The competitors will start in Staten Island -- cross the Verrazano-Narrows Bridge through Brooklyn, Queens, the Bronx and finally Manhattan's Central Park.

After the professional women, the first wave includes the professional men, starting at 9:50 a.m. The other three waves begin at 10:15 a.m., 10:40 a.m. and 11 a.m.

Strains of "New York, New York" were heard at the start as the marathoners begin their journey and helicopters flew overhead.

Theresa Giammona, 45, of Garden City, is one of the competitors.

She had never seen herself as a runner. "I couldn't even run once around the track," she said before the marathon.

But she started training last this spring and is clocking 13 minutes a mile.

"I want to finish before dark and cross the finish line," said Giammona, who raised about $40,000 for her favorite charity: Answer the Call for the New York Police and Fire Widows and Children's Fund, which offers financial support and a network for families who have lost loved ones in the line of duty.

Giammona lost her husband FDNY Lt. Vincent Giammona on 9/11. He had expected to run in the 2001 marathon in celebration of his 40th birthday. "He put in his name and got in. He was really pumped up," said Giammona, who has raised four daughters.

On Nov. 1, 2001, her husband's fellow firefighters, relatives and college friends ran on his behalf. "My children were little then, so I couldn't do it," said Giammona, who relishes the opportunity to run this year in memory of her husband.

Running with Giammona is Firefighter Josephine Smith, whose father FDNY firefighter Kevin Smith also perished on 9/11. In memory of her father, Smith has been training with Giammona for the marathon -- a partnership that has helped each.

"We don't wear plugs when we run together,'' said Smith of Selden. "We talk to each other about Vinny and my father, or what I am going through . . ." said Smith. "It's fantastic. It helps the both of us. We keep each other motivated."

Both women will run with other FDNY members and plan to cross the finish line in Central Park together.

Preparations for the city's 45th marathon closed the upper level of the Verrazano-Narrows Bridge at 11 p.m. on Saturday, according to the Metropolitan Transportation Authority. The lower level will be shut from 7 a.m. to 3 p.m. on Sunday.

The best thing motorists can do -- if they have to drive in or through the city -- is to start very early, before closures, or very late, after reopenings.

"The bridge reopens at 3 p.m., but don't try to get on it at 3:05 p.m. You'll get snagged in traffic. Plan ahead and come back later in the day," said Alec Slatky, spokesman for AAA of New York.

Police said 1,800 officers will be deployed along the marathon parade route through Brooklyn, Queens, Manhattan, the Bronx and Manhattan again, where it ends in Central Park. About 50,000 runners are expected to take part, cheered on by more than 1 million spectators lining the route.

Police and other first responders conducted a tabletop exercise Thursday at Police Headquarters to go over potential problems during the marathon. In one scenario, a man rammed his SUV through a parade barricade in Queens, jumped out and began slashing spectators. Fire, police and ambulance officials explained how they would respond.

With Robin Topping, Joan Gralla and Anthony M. DeStefano