Stocks will be struggling with a key question in today’s trading action – was Friday’s jobs miss a weather-related payback or a recurrence of a fundamental weakness along the lines what we encountered around this time in 2011 and 2010? I would say it’s all weather, with the boost from the warm winter months getting reversed in March, but the overall positive trend line remaining in place. That said, the market’s first reaction to the sub-par payroll reading will most likely be negative.

In the run-up to the March jobs report, a number of economic forecasters had started wondering about the extent of temporary contribution from this year’s unusually warm winter. Even Ben Bernanke found the labor market strength of the last few months difficult to reconcile with the relatively slow pace of underlying economic improvement. We will know for sure only after we get the April jobs numbers in about three week, but weather seems to be the most plausible explanation for March’s unexpected under-200K labor market reading.

The government’s monthly household survey (the unemployment rate comes out of this report) lists the number of people not at work because of weather. The non-seasonally adjusted March reading showed an 82K drop on this count, significantly below the historical level for this month. The same number for the preceding three months was above trend compared to history, meaning that the weather gains of the pre-March months likely got reversed in March. The persistent downtrend in weekly jobless claims and other labor market indicators over the last many months would argue against a fundamental weakness in underlying momentum.

In corporate news, the first quarter earnings season gets underway unofficially on Tuesday with Alcoa’s ( AA - Analyst Report ) report, with aggregate earnings growth expectations at their lowest level since the start of earnings recovery in 2009. Barring unusual negative surprises, I would expect this earnings season to be largely uneventful. Given the low hurdle rates as a result of subdued expectations, the focus will be management guidance for the coming quarter, particularly with how they see the Chinese and European situation impacting their profitability.

In other news, shares of AOL ( AOL - Snapshot Report ) will be in the spotlight today after the company announced the sale of over 800 patents to Microsoft ( MSFT - Analyst Report ) for $1.06 billion in cash.