Snow Patrol has been forced to postpone the rest of its North American tour to allow lead singer Gary Lightbody to recover from polyps on his vocal cords. Several shows had already been postponed with the hope that Lightbody would recover in time to play at least some of the tour, but doctors have now advised him not to sing again until mid-July. The outing began May 23 in Denver but Lightbody’s voice was quickly in shambles, forcing the first postponement on May 29 in Atlanta. The tour was to wrap June 27 in New York. “It is completely my fault for not taking better care of my voice,” Lightbody wrote in a recent post on Snow Patrol’s Web site. “The voice is an instrument and I should learn to take care of it as such. When I have it back and working again I won’t take it for granted anymore.” The shows will be rescheduled between Sept. 6-30, with full details to be announced. All tickets from the postponed dates will be honored for the new bookings. Stops in San Diego and Las Vegas will also be added to the itinerary. Snow Patrol was to be touring in support of its new Interscope album, “Eyes Open,” which debuted last month at a career-best No. 34 on The Billboard 200. The single “Hands Open” is No. 24 this week on Billboard’s Modern Rock chart.