The U.S. economic data has shown signs of weakening for the past three months running, despite some real optimism that developed in the fourth quarter of 2013.

That optimism was based on the end to the fiscal stalemate in Washington in October, a 4.1% GDP growth rate in the third quarter, and 3.2% growth rate in the fourth quarter (subsequently revised down to just 2.4% growth). Sky-high retail sales data that was subsequently revised sharply downward also contributed to economists’ bright mood at the end of 2013. However, poor weather seems to have interrupted the upward trajectory. The effects of abnormally cold and snowy weather seem real, but the weather is not the only cause for the recent weakness, in my opinion. Parts of the economy, including the housing sector, were already showing some slowing even before the cold weather arrived.

Putting the weather aside (poor weather will likely make the first quarter weaker than it otherwise would have been, but could potentially make the second quarter stronger), there is an ongoing debate about the underlying strength of the economy. Prior to the weather news, many economists believed the economy was set to grow 3.0%–3.5% or even more in 2014. They believed that the economy had finally reached its so-called escape velocity.