After a summer of rising unemployment and missed payments, 11 percent of Tampa Bay mortgages were 60 or more days late as of September 30, according to TransUnion, the country's third largest consumer credit rating agency. Just a quarter earlier, on June 30, the delinquency rate was 10 percent. A year earlier, 6.83 percent of mortgages were 60 days behind. Mortgage defaults in the rest of Florida were worse. As of Sept. 30, 13.34 percent of mortgages were late statewide. Short sales and government-backed loan modifications will help keep many of those properties out of foreclosure. But economists predict another wave of foreclosures next spring if interest rates tick up and adjustable rate mortgages taken out during the housing boom reset.