Mortgage rates are known to rise without much notice – if any! From MND:
http://www.mortgagenewsdaily.com/consumer_rates/469946.aspx
Mortgage rates are having a rough couple of weeks. Yesterday saw rates approach the previous 2015 highs set on March 6th. Today’s rates moved slightly higher still, setting a new 2015 high.
The average lender is now quoting conventional 30yr fixed rates of 4.0% on top tier scenarios, though 3.875% is still available in some cases. This is a substantial increase from the 3.625% rates seen just a few short weeks ago.
The last time rates spiked (June 2013), it spurred the market as buyers grabbed what they could while rates were still under 4%. But now that prices are more than 10% higher, the impact might go the other way.