A low unemployment rate, a strong housing market, booming car sales: Some pictures of the U.S. economy are downright rosy.

But there could be a storm brewing — a rumbler that has some people mentioning another "r" word: recession.

It has been whispered about at the highest levels for some time now. In February, the Wall Street Journal's survey of global economists showed that the gurus of the green stuff pegged the odds of recession in the next 12 months at 21 percent — twice that of a year ago and the highest since 2012.

A recession is defined as a drop in business, trade and industrial activity signaled by a decline in gross domestic product for two consecutive quarters. And no one likes what comes with that: job cuts, wage freezes, reduced working hours and frazzled household budgets as businesses cope with low demand by reducing expenses.