Home prices rose for the fourth month in a row during August and suffered a smaller-than-expected annual drop, according to a report issued Tuesday.

Prices in the S&P Case-Shiller Home Price index of 20 cities rose a non-seasonally adjusted 1.2% in August. It was the fourth consecutive monthly increase and followed a 1.6% gain in July.

Prices were down 11.3% versus August 2008, but that drop was less severe than expected. Analysts surveyed by Briefing.com had forecast an 11.9% year-over-year drop.

"Broadly speaking, the rate of annual decline in home price values continues to improve" said David Blitzer, chairman of Standard & Poor's index committee.

While many U.S. markets remain down versus this time last year, the relative rate of decline "has shown some real improvement," Blitzer added.

Home prices improved on an annual basis in 19 of the 20 major metropolitan markets in the survey.

State by state. In California, home prices have recovered notably from depressed levels in recent months, according to the report.

Home prices rose 2.8% in San Francisco during August, while San Diego prices were up 2.5% and Los Angeles gained 1.8% in the month.

Minneapolis had the biggest increase, with home prices rising 3.2% from July to August.

But prices continued to slide in areas that have been hit hard by foreclosures. Prices dropped 0.5% in Cleveland and 0.3% in Las Vegas during August.

A shaky recovery. Overall, the housing market has been stabilizing as low home prices and attractive mortgage rates, as well as government tax credits, have revived anemic home sales.

However, the market remains hampered by unemployment, which rose to a 26-year high last month. And real estate analysts warn that the expiration of a popular new homebuyer tax credit next month could stifle the rebound in home sales.

The improvement in home prices could also be hindered by a "wall of supply" coming to market this spring from private sellers and foreclosures, warned Ian Shepherdson, chief U.S. economist at High Frequency Economics.

Given the long-term challenges facing the housing market, the outlook for home prices remains grim.

Home values are predicted to drop in 342 out of 381 markets during the next year, according to a recent study by financial information and analysis firm Fiserv.

Fiserv expects the national median home price to drop 11.3% by June 30, 2010.

SOURCE: Ben Rooney, CNNMoney.com staff reporter 10-27-09