Friday’s weak jobs report has taken some of the air out of the optimism balloon for the US macro outlook, but in the search for things to worry about I’m more inclined to focus on the discouraging trend of late with personal income. To be precise, the decelerating year-over-year change in personal income less transfer receipts (Social Security checks, for instance) is beginning to look troubling. It may turn out to be noise, as an earlier dip proved to be. But we’re again entering a phase when there’s minimal room for disappointing numbers with the monthly reports on personal income. The data on payrolls, by contrast, still looks relatively strong for the critical year-over-year comparisons.

I don’t want to overplay the potential for trouble with the personal income numbers, at least not yet. As Doug Short reminds, the quirks in the government’s calculation for income may be distorting the trend at the moment. Keep in mind that the statistical twists may get worse before they get better. Taken at face value, however, the 1.2% annual rise in real personal income less transfer receipts is sharply lower vs. previous months and so this indicator is running out of road.

Income growth, of course, is a bedrock for a healthy economy, particularly in the US, where consumer spending is such a big piece of economic activity. Given the soft data on this front lately, the next release of personal income numbers on January 31 deserve close attention. Unfortunately, year-end seasonal issues related to taxes and other complications may leave us no more the wiser about the true trend on this front.

The good news is that the economic data generally still looks encouraging. Moderate growth continues to prevail when we consider a broad spectrum of numbers, as last month’s US Economic Profile shows (I’ll publish an update next week). But the business cycle is constantly evolving. For the moment, the signs of distress remain in the minority. Some choose to point to the surprisingly weak jobs report for December, although it’s too early to let one number cast aspersions across a generally upbeat macro profile. The year-over-year trend in private employment continues to advance at near a 2% rate, or roughly the pace we’ve seen in recent history. For now, the soft December monthly increase appears to be an outlier event for payrolls.

Personal income, by contrast, looks darker via a sharply decelerating rate of year-over-year growth. But it’s going to take some time to decide if this is noise or a legitimate warning sign for the economy.

Meantime, the week ahead brings more context for deciding how the big picture is shaping up, starting with tomorrow’s December report on retail sales, followed by the weekly jobless claims report on Thursday, and a pair of key updates on Friday for December: industrial production and housing starts.

As usual, truth and clarity in matters of the economic trend arrive in a familiar pattern: drip, drip, drip.