By Patricia Reaney

NEW YORK (Reuters) - New looks on the runway at New York Fashion Week will be met with changes behind the scenes as designers tweak their shows and schedules to meet the needs and expectations of digitally engaged consumers.

About 100 designers will showcase their collections at the fashion fest that begins on Thursday. The looks are expected to hark back to the 1980s and feature shirtdresses, well-defined, generous cuts, ruffles and clothes that transcend the seasons.

"I think we are going to see a lot more seasonless merchandise; in other words it is going to be more about layering," said Lizzy Bowring, head of the catwalks department at trend forecasting and analysis company WGSN.

Another theme will be athletic-inspired fashion and street-style looks, popularized by singers Kanye West, Beyonce and Rihanna, whose Fenty Puma collection will be available in pop-up shops and stores this week.

"A lot of people are going into this realm and I think it is what people are actually buying too," said William Kahn, fashion market and accessories director at Hearst Magazines, Town & Country.

"The celebrity culture is so strong right now, if Beyonce or Rihanna put their name on something it can create a major trend in itself."

While many designers will be showing 2017 Spring/Summer collections that will not be in stores for months, others will try a different format by showing in-season fashions.

Some brands are opting for the "see now, buy now" model with the designs on the runway, or capsule collections, immediately available to customers. Appointment-only presentations are another option, as are online shows and combining men's and women's fashions into one presentation.

"It is a moment of change in fashion and experimentation, in terms of making fashion week relevant now," said Kahn. "Before fashion week was to show people what was coming out in six months, now it is to sell clothes now."

The changes are in line with the results of a study released in March by the Council of Fashion Designers of America, which administers the fashion week schedule. After questioning 50 industry insiders about the future, the report found the overall consensus was "the time is ripe for change."

Ken Downing, senior vice president and fashion director at luxury fashion retailer Neiman Marcus, supports the shakeup in the fashion week system.

"I am a huge proponent of people showing their collections in real time and within the season the clothes are going to be in the store," he said.

Once the domain of fashion editors, buyers and well-heeled clients, fashion week now attracts more than 230,000 attendees and a huge online audience in real time.

Kahn credits social media and fashion bloggers for changing the game.

"They have made it so much more accessible for everyone to see what is going on," he said. "When everyone gets to see it, everyone is a fashion editor."

(Editing by David Gregorio)