The U.S. automakers have been facing 2 crucial problems after the two storms that battered parts of Texas and Florida: bulging new-vehicle inventories and an oversupply of off-lease vehicles. This Tuesday, they will reveal their car sales for September, but we are already convinced that their shares will be higher than ever, thanks to the demand for vehicles to replace those damaged and destroyed by Houston’s floods. Analysts expect September to show the first monthly increase in vehicle sales this year -- though their previous forecasts of sales gains for the industry in March, May and August proved inaccurate. Any increase likely would be minimal; Edmunds projects a 0.4 percent rise, and Kelley Blue Book expects a 0.7 percent gain. However, either amount would be enough to push the industry's annualized selling rate to 17.5 million units -- the highest of the year. During the height of the storm, online car searchesin Houston were down 25 percent -- from an Aug. 4 baseline -- but as of Sept. 17 were up 18 percent.