If you’re one of those homeowners who has looked at selling or refinancing in the last six months, you probably got a rude awakening from the real estate appraiser — namely: your house isn’t worth nearly what it was two or three years ago. This shouldn’t be a surprise, given the global economic crisis and dire news about foreclosures, which hit a record high in the second quarter. But a low valuation can sink a home sale and change the arithmatic of a refinancing. As this recent story in the Globe points out, low appraisals can also be the result of a paucity of recent sales in the area. But data out from real estate tracking Web site Zillow suggests that home values in Belmont may have turned a corner, after plummeting over the last two years. Zillow’s Real Estate Market reports have Belmont home values up by 3.9% in the second quarter 2009, compared with the same quarter in 2008. The average home price, now at $622,000 has come up abruptly from its nadir in Q1, when Zillow’s index of home prices and values was down to $585,000. That suggests that buyers are showing up for Belmont homes (anecdotal evidence from a few drive-bys at open houses confirms this), even as neighboring communities like Watertown and Cambridge are still seeing prices down from a year ago. Interesting data…but this is just a snapshot. It will be interesting to see how the market looks at the end of Q3.