Mortgage rates had been walking a slow, steady path of improvement since hitting 8 month highs on June 10th.  From then on, there were only 2 days where rates did NOT improve.  As of last Friday, the average conventional 30yr fixed rate quote for top tier scenarios was as close to 4% as it has been since the beginning of the month.  Today's spike brings the average solidly back in favor of 4.125%.

There are several ways to view and understand this weakness.  First of all, 2015 is simply a more volatile time for interest rates, and that's not expected to change any time soon.  More specifically, Friday marked 3-week lows.  That's a pretty good run for a high-volatility environment that's mainly seen rising rates for 2 months, and it's the reason I noted on Friday that rates were still technically in an "uptrend" in 2015 despite recent improvements.  Today served as a painful reminder of that.