WASHINGTON (AP) — Long-term mortgage rates rose for a second straight week as the average 30-year fixed mortgage rate increased to 3.91 percent, from 3.85 percent a week ago. Mortgage buyer Freddie Mac says the 15-year home loan, frequently used by homeowners who refinanced their mortgages, also jumped, rising to 3.21 percent, from 3.15 percent. Mortgage rates have picked up a bit in the past month.Read more on NewsOK.com