After five years of silence (during which songwriters Harriet Wheeler and David Gavurin had a baby) the Sundays are back, thank God, with their third album. While the delicious “Summertime” delivers the bright, convertible-top-down pop of their 1990 breakthrough debut, static is suffused with melodic Celtic melancholy. As always, Gavurin’s textured, jangly guitar provides the perfect counterpoint to Wheeler’s airy vocals.