Sales of new cars and trucks in August were a bright spot in the economic greige, continuing a year-long trend that analysts say will only diminish mildly by year's end.

All the Detroit-based automakers reported double-digit sales increases for the month, joined by ebullient numbers at Toyota, Volkswagen, and Kia.

Sales trended up noticeably from July's strong numbers. J.D. Power and Associates had forecast that August would deliver a retail-level seasonally adjusted annual rate (SAAR) forecast of 12.3 million units, and an overall SAAR of 14.5 million units, and the final numbers could exceed those projections.

The enthusiasm in dealer showrooms could be a result of sell-downs in advance of the new model year, which brings some important new vehicles, like the Ford Fusion and Escape, Chevy Malibu, and Honda Accord. Dealers are spending less to move the 2012 models--$106 less per vehicle, Power says--and so far, the automakers haven't spooled up production to unsustainable levels, says John Humphrey, senior vice president of global automotive operations at J.D. Power and Associates.

"Going forward," he says, "this discipline will be tested as demand looks to cool somewhat through the balance of the year."

The slowdown is expected to arrive at the traditional point late in the season, when weather dampens shopping. But it could also be aggravated by continued economic difficulties. New unemployment numbers are due this week, and early indications are for no improvement over July's 8.3 percent. Likewise, while consumer confidence rose unexpectedly in July, so did gas prices, which reached an all-time Labor Day weekend peak.

For the year, analysts expect sales to remain healthy. LMC Automotive has cut its forecast somewhat, and now says total light-vehicle sales for 2012 will come in at 14.3 million units, with retail sales forecast at 11.4 million units.

"The overall picture in 2012 remains positive," said Jeff Schuster, senior vice president of forecasting at LMC Automotive.

LMC's figures are at the middle of the spectrum forecast by the automakers themselves, with Chrysler predicting 14 million units, and GM slightly more pessimistic at between 14 and 14.5 million units.

Which automakers are feeling the power of August sales, and which are still weak? These are the August 2012 figures, as reported by the automakers:

General Motors: GM (NYSE: GM) reports its sales were up 10 percent in August 2012, with 240,520 units moved by its four brands. At GMC, for example, cutting fleet sales 35 percent hasn't hurt overall numbers. It's up 4 percent overall, with its big Acadia crossover up 26 percent, and the compact Terrain up 16 percent. Chevrolet rose to 169,978 units, up 11.3 percent--the same gain as Cadillac, which sold 14,704 vehicles. Buick's sales of 18,000 units included record sales of the Verano, for a 12.4-percent increase.

Ford: Ford (NYSE: F) watched its sales grow by 13 percent as its most popular sedans, hatchbacks, crossovers and pickups all had double-digit gains. The F-Series truck lineup was up 19 percent, at 58,201 units; while the subcompact Fiesta was off 28.4 percent to 4,176 units, the Focus sedan and hatchback grew their sales by 35.3 percent to 19,073 units. Ford's Fusion sedan continues to be strong in its final model year, up 21 percent while a new version makes its way to production; the Escape crossover is already transitioning into a new body style, and its sales increased 36.8 percent. Among its big utility vehicles, Ford watched as sales of the Explorer were up 33 percent, and the Edge rose 23.3 percent; the Flex was down 6.7 percent.

Toyota / Lexus / Scion:Toyota (NYSE: TM) has teased August sales of 188,520 units in August 2012, up 40.2 percent. More details to come.

Chrysler: Chrysler says it sold 148,472 vehicles in August, up 14 percent from a year ago, for its best August since 2007. Brand by brand, Fiat sales rose 34 percent to 4,150 units; Chrysler was up 25 percent to 28,070 vehicles; Jeep rose 5 percent to 42,839 sales; Dodge's numbers were up 13 percent to 47,348 vehicles; and Ram sold 26,065 vehicles. Among individual vehicle lines, the new 2013 Dodge Dart posted sales of 3,045 units--but the Dodge Durango SUV was off 45 percent from a year ago.

Nissan / Infiniti: Nissan North America says it sold 98,515 cars, trucks, and crossovers in August, up 7.6 percent from August 2011. The Nissan brand accounted for 87,360 of those units, with the new 2013 Altima taking 25,889 of those sales, up 12.5 percent. Infiniti was up 23.6 percent to 11,155 units; while the G sedan had its best August ever, the JX crossover is already the second best-selling vehicle in the luxury brand's lineup.

Hyundai: The Korean automaker filed an early notice via Twitter: "#Hyundai sales of 61,099 (+4%) despite tight inventory. US plant 3rd shift in Sept will help us better meet demand. ^jfk"

Kia: Kia sales rose to 50,028 units in August, up 21.5 percent over a year ago. Its Optima sedan already has sold more than 100,000 units in 2012; both the Sorento crossover and Soul hatchback are on track to do the same for the full calendar year.

Volkswagen: Volkswagen says it sold 41,011 units in August, up 62.5 percent on last August, and up 37.6 percent on the year; it's the brand's best August since 1973. The Passat sold 10,090 units--about three times as many as the Fiat brand--while Jetta sales were up on the month.

Mitsubishi: Not yet reported

Porsche: Porsche says it sold 3,026 vehicles in August, up 39 percent from August 2011. 

Jaguar / Land Rover: Jaguar Land Rover sales rose again in August, as the car side of the business showed a spark. Land Rover moved 3,727 units, up 33 percent while Jaguar sold 1,029 vehicles, up 27 percent--before its new all-wheel-drive vehicles are available. The combined brands watched sales rise 31 percent to 4,756 units; on the year, they're up 18 percent.

Suzuki: Not yet reported

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