* Automakers may post first US monthly rise since Oct 2007

* Industry not seen approaching August rate rest of 2009

Ford Motor Co (F.N) will report a U.S. auto sales increase in August and the industry may post its first monthly year-over-year sales rise since October 2007, the automaker's chief sales analyst said on Monday.

For the industry, the seasonally adjusted annual rate of sales in the United States is likely to come in above last August's 13.6 million rate, but below the top of recent forecasts after buying dropped off near the end of the month, Ford's George Pipas said.

The annualized rate of monthly sales is not expected to approach the August peak for the rest of 2009 due to the end of Washington's Cash for Clunkers program, tight inventories and a weak domestic economy, he said.

Right now, the economy is not sufficiently expanding to support the level of sales we had in August, Pipas said.

Automakers reported U.S. sales totaling 1.25 million vehicles in August 2008, the last time the industry broke the 1 million mark on a monthly basis. It came close in July with the start of the clunkers incentive program.

U.S. auto sales reached an 11.2 million-unit sales rate in July, the best month of 2009, due to brisk sales from the incentive program, and analysts have forecast an August rate ranging from 12 million to nearly 16 million vehicles.

Pipas said inventories had been tight at the start of August, after the clunkers program spurred sales in late July, but then inventories tightened sharply later in August.

It will probably take at least until the end of September for inventories to begin to approach normal levels and they will still be relatively lean at end of next month, Pipas said.

When we planned our production for the fourth quarter ... we did so with our eyes wide open, with a full understanding that sales in the next four months would not be as high as what we have seen in August.

Ford had 295,000 cars and trucks in inventory at the end of July, about a 48-day supply, and that will be lower at the end of August, Pipas said. (Reporting by David Bailey, Editing by Maureen Bavdek)