Home prices jumped nearly 11 percent in April from a year ago, according to the S&P/Case-Shiller 20-city home price index.

Prices are up 22.6 percent since bottoming out just over three years ago, but are still 18 percent below the peak set in July 2006. And year-over-year gains are slowing.

"Although home prices rose in April, the annual gains weakened," says David Blitzer, Chairman of the Index Committee at S&P Dow Jones Indices. "Last year some Sunbelt cities were seeing year-over-year numbers close to 30 percent, now all are below 20 percent."

Five cities posted strong month-over-month gains: Atlanta, Boston, Chicago, San Francisco and Seattle, all of which jumped at least 2 percent.

Low mortgage rates, which the Federal Reserve is expected to keep reined in through mid-2015, and gains in the job market should continue to help the housing market, according to Blitzer.

But don't get too comfortable.

"Housing is not back to normal," said Blitzer, "Prices are being supported by cash sales, low inventories and declining foreclosure sales. First-time home buyers are not back in force, and qualifying for a mortgage remains challenging. The question is whether housing will bounce back before the Fed begins to tighten sometime next year."