U.S. light-vehicle inventory increased in September from August in volume and days’ supply, both normal trends with the new model year that begins in October.

September’s inventory, combined with forecast production for the U.S. market, left automakers well-equipped to meet the fourth-quarter 15.9 million seasonally adjusted annual rate LV sales will have to reach in order for 2013 to finish at the 15.6 million units expected by WardsAuto.

Days’ supply increased from 55 in August to 62 last month, a little bigger jump than usual, but expected because of the effect of the Labor Day weekend included in August’s sales results. In 2012, September days’ supply increased to 59 from 58 the prior month.

Total September LV volume was 3.05 million units, 9.4% above year-ago and 4.6% higher than August, the first time since 2007 the month topped 3 million.

Automakers ended the month with 1.45 million cars in stock, up 4.7% from year-ago, and 1.61 million trucks, 2.9% over like-2012.

Inventory of domestically made LVs stood at 2.45 million units, 9.4% above September 2012, and imports were up 9.7% to 600,036.

Ford, which nearly caught industry leader General Motors in U.S. sales in September, increased its inventory 8.0% from August, the most of any company. At the end of August, Ford’s inventory was 30% above year-ago, a main reason its sales surged 15.2% in September over like-2012. With inventory still a hefty 28.9% above year-ago going into October, Ford is in position for another strong month now that several of its strong-selling vehicle lines have inventory aligned more closely with demand.

Of Ford’s core products, only the Explorer cross/utility vehicle has less stock than a year ago.

Ford and Chrysler are the only automakers with more large pickups in inventory than a year ago. The increases are significant because large pickups are undergoing the fastest growth among all major segments, and October-December likely will be the high-volume period for the segment this year. Combined volume for the other segments is expected to decline from the previous two quarters.

Segment-leader GM’s Chevrolet Silverado and the GMC Sierra have combined inventory 6.1% below year-ago, while Toyota Tundra is down 16.7% and Nissan Titan is short by 45.2%.

GM, coming off a sales decline in September, increased LV inventory 6.6% from the prior month. Despite not having as much large-pickup inventory on hand as last year, the automaker does have enough to continue recording sales gains, especially with the majority of its Silverado/Sierra stock consisting of its redesigned ’14 models.

GM also improved the inventory picture of the Chevrolet Cruze sedan after sales nosedived last month in part due to a lack of availability.

In addition to Ford and GM, other automakers increasing their month-to-month stock levels faster than the entire industry were Chrysler (6.0%), Mitsubishi (7.9%), Nissan (15.4%) and Toyota (4.7%).

The increase was particularly important for Toyota. After posting double-digit sales increases from June through August, its inventory tanked by the end of summer, and market share declined in September for the first time since May.

By segment, inventory for Middle Cars and the combined luxury-sedan segments increased faster than the industry from the prior month. Much of the strong month-to-month growth in trucks occurred in large-size vehicles including CUVs, SUVs, pickups and vans.

Not surprisingly, the increases coincide with October, as well as entire Q4, a strong period in share for luxury cars and large trucks.

With October the official start of the model year, most ‘14 LVs will be in full availability. Some notable exceptions will be Dodge Dart; Ford F-150 and Edge; Hyundai Elantra; Nissan Frontier, Sentra and Xterra; and Toyota Highlander and RAV-4.

Those vehicles are scheduled for late ’14-model production starts. Highlander, because it will be redesigned, starts ’14 production in November.

Vehicles already with a high mix of ’14 models in their inventory include the Silverado and Sierra; Chevrolet Impala; Ford Fiesta; Honda Accord, CR-V and Odyssey; Jeep Compass, Grand Cherokee and Patriot; Nissan Versa and Versa Note; and Subaru Legacy and Outback.

hstoddard@wardsauto.com