Home prices are up for the first time since July 2006, according to the Case-Schiller Index. This comes one day after we reported that home sales increased, by 11 percent, for the third consecutive month. What a week for the American home!

But wait, say my trusted bloggy advisers on housing issues, Calculated Risk and Felix Salmon. We're not out of the woods yet...

First, CR notes that, these figures were for May, and May home prices often rise. In fact, seasonally adjusted data shows a price decline from April to May. As a result, CR predicts we'll actually see prices further decline this fall.

Salmon doesn't offer much more cheer. He takes the long view, explaining that the Case-Schiller Index uses January 1, 2000 as a baseline of 100, which helps us make clean decade-long comparisons. At the housing's bubbly height, Miami and Los Angeles were nearing 300. Today, they're both down more than 40 percent. And Detroit? It's the only major city in single digits, at just 70. Salmon's analysis of today's report:

If housing kept track with CPI inflation, the Case-Shiller index would be at 125 now; in fact, it's at 140. But of the 20 cities on the Case-Shiller list, just 9 have managed to outperform inflation...The big outperformers -- New York and Washington -- more than make up for the underperformers...

My gut feeling is that this means New York and Washington have significantly further to fall, in terms of housing prices; even Miami, at 144, is still looking pretty rich. San Francisco might look cheapish at 120, but it was artificially inflated, at the beginning of 2000, by the dot-com bubble: just a year earlier it was at 85.

So while the lead story in housing today might give you the sense we've already started rounding the corner, it's important to note that these seemingly positive numbers come with some serious caveats.