Surprise! The bad economic data is turning

Traders work on the floor of the New York Stock Exchange.
Lucas Jackson | Reuters

For weeks, Wall Street forecasters missed the mark on one economic report after another, giving credence to the view that winter weather was not the only thing holding back the economy this year.

But the negative data stream appears to be turning, with more big numbers coming in stronger-than-expected - including recent beats on the consumer price index, ISM manufacturing, housing starts, new home sales and .

Traders have been tracking this change in data via the widely-followed Citigroup Economic Surprise Index, which appears to be bottoming.