Freddie Mac released its weekly update on national mortgage rates this morning, showing average fixed mortgage rates moving slightly higher for the week but still remaining near historic lows..

Thirty-year fixed rate mortgages (FRM) bounced back after last week's big drop, rising three basis points to end at 3.57%. Shorter-term 15-year FRMs rose similarly, up four basis points to 2.76%.

But the more interesting movements took place among adjustable-rate mortgages. 5/1 ARMs actually outgrew their longer-dated counterparts, spiking seven basis points to hit 2.68%, their highest level since January. One-year ARMs, in contrast, fell one basis point, to 2.62%.

Commenting on the numbers, Freddie Mac Vice President and Chief Economist Frank Nothaft said that  mortgage rates remain "low and relatively steady," and observed that this is "invigorating the housing market. For instance, existing home sales over January and February experienced the strongest two-month pace since November 2009, while new home sales were the strongest since August and September 2008."

Nothaft further cited a Conference Board report that "the number of consumers expecting to purchase a home over the next six months rose to 5.6 percent in March, the second highest share since data was first collected in February 1964."