After adding 8 basis points Wednesday, the 30-year fixed-rate mortgage average surged higher Thursday. Jumping 32 additional basis points, the flagship average is now up to 7.70%, exceeding the late May high-water mark of 7.65%, which was estimated to be a 20-year high.
Rates on 15-year loans also rose dramatically Thursday, gaining 27 basis points to average 7.11%. That's…