US July auto sales likely rose 2.4 per cent from a year earlier, but full-year sales will not match last year's record, forecasters JD Power and LMC Automotive said on Friday.

LMC now expects that 17.4 million new vehicles will be sold in all of 2016, down 0.1 per cent from 2015. It would be the first annual decline in US auto sales since 2009.

On Thursday, Ford Motor Co became the first major automaker to declare that the long US auto market recovery was at an end.

Brian Johnson, auto industry analyst at Barclays, earlier this month changed his outlook for the US auto market from "plateau" to "eroding plateau”.

Johnson told Reuters that Ford's assessment of a weakening market was important for market observers.

"Ford acknowledged for the first time many of the pressures we have been talking about for the past few weeks," Johnson said. "There's a big difference between analysts and writers saying this market is poised to get softer, and hearing it from one of the largest players in that market."

Backing out of medium and heavy trucks to include only vehicles in the LMC forecast, the midpoint of Ford's new outlook would be about 17.3 million vehicles, weaker than LMC's prediction.

While their annual forecast is getting more bearish, JD Power and LMC say July will be extremely strong, with a seasonally adjusted annualised rate of sales of 18.1 million vehicles.

Johnson said July was an example of a strong month amid a weakening trend.

"This is proving to be a dynamic year in terms of automotive demand volatility," said Jeff Schuster, LMC forecaster.

LMC was the most bullish among a group of analysts that included Barclays, RBC Capital, Edmunds.com, Kelley Blue Book, WardsAuto and TrueCar, which forecast July US sales on an annualised basis in a range from 17.5 million to 17.8 million vehicles.

On average, the forecasters said the four biggest automakers will see little change in their sales from a year ago: General Motors Co, down 1.3 per cent; Ford down 1 per cent; Toyota down 2.7 per cent; and Fiat Chrysler Automobiles NV up 1 per cent, using the updated year-ago sales figures for FCA.

FCA restated its monthly auto sales dating to the start of 2011 earlier this week.

JD Power said incentive spending by automakers rose in July to an average of $3,680 per vehicle, the highest for any month this year.

Major automakers will report US July sales on Tuesday. – Reuters