PREVIEW-US existing home sales seen at highest since July 2007

* What: U.S. existing home sales for October

* When: Nov. 23, 10 a.m. (1500 GMT)

* Economists' median forecast: 5.70 million annual rate

By Julie Haviv

New York, Nov 23 (Reuters) - Sales of existing U.S. homes likely rose for a second consecutive month in October, reaching their highest since July 2007, according to a Reuters poll, as buyers scrambled to take advantage of greater affordability and a first-time home buyer tax credit.

The survey of 29 economists predicted sales of previously owned homes climbed to a seasonally adjusted annual rate of 5.70 million, the fastest pace since 5.73 million units were sold in July 2007 and up from 5.57 million units in September.

Forecasts ranged from as low as a seasonally adjusted annual rate of 5.26 million to as high as 6.00 million units.

Existing home sales tally the number of previously constructed homes for which a sale closed during the month.

The National Association of Realtors will release U.S. existing home sales data on Monday at 10 a.m. (1500 GMT). (Additional reporting by Lucia Mutikani; Editing by Dan Grebler) ((Reuters Messaging: julie.haviv.reuters.com@reuters.net; email: julie.haviv@thomsonreuters.com; Tel: +1-646 223-6153))