CIAO, MACY’S: Alberta Ferretti, in town Tuesday for the official launch of her Alberta Ferretti for Impulse collection at Macy’s, couldn’t believe the July-like temperatures in Gotham. “I am lucky woman,” she said at the party on Macy’s third floor. “This is a summer collection, and outside it’s like summer. It’s beautiful.” Macy’s had literally rolled out a red carpet for the designer and her friends, including Wendi Murdoch; nine models sported looks from the collection, and waiters passed around Popbar gelato icicles, which were highly popular with the designer’s fans while they were sifting through the racks of clothes. “It’s going to do very well,” said Nicole Fischelis, Macy’s group vice president and fashion director, smiling.