Even if Thursday's economic data comes up punk, markets may just write it off to bad weather.
But stocks could continue to waffle after traders found excuses Wednesday to sell following the release of Fed minutes and against the backdrop of deadly protests in Ukraine. Stocks did not cave on a 16 percent drop in housing starts, however, as traders blamed bad January weather for disrupting building activity.
Facebook's late-day announcement of a plan to buy WhatsApp for $16 billion in stock and cash could stir up interest in Internet and other tech names Thursday. Facebook fell nearly 5 percent at one point in late trading.
Since hitting bottom Feb. 3, the stock market has galloped higher, and the S&P had recovered nearly all its 2014 losses by Wednesday morning. It touched briefly on 1,847, just below its record close of 1,848.
But traders found plenty of reasons to lighten up during the day, including an IMF report at midday cautioning on emerging markets problems. Stocks initially seesawed after the 2 p.m. release of Fed minutes but then sold off into the close.
While the minutes were viewed as revealing little new, that several members said it would soon be time to raise rates got some attention and made the Fed sound a little more hawkish than it has been. Overall, though, it appeared to be signaling no changes and to be committed to tapering its bond-buying program.
The minutes also noted that weather may have affected jobs data. Treasury prices fell, and the 10-year was yielding 2.74 percent after the release.
(Read more: Winter weather freezing corporate profits)
"There's a lot of noise and counterforces in the market at this point," said Ian Lyngen, senior Treasury strategist at CRT Capital. "On a day when you had weak housing data, easy to dismiss inflation data and a relatively benign Fed minutes, we're under a little pressure here."
Since the beginning of 2013, the stock market has closed higher just twice on the 10 days the Fed minutes were released.
"We've had real big gains in the market, so people start looking for excuses to take profits, and ... the Fed minutes days for more than a year now have been bad days for equities," said Paul Hickey, co-founder of Bespoke.
The S&P 500 ended the day down 12 at 1,828, while the Dow was down 89 at 16,040. The Nasdaq had its first negative session in nine, falling 34 points to 4,237.
(Read more: Foreigners hit sell button on US assets in December)
"It's tired," said Steve Massocca of Wedbush Securities. "We're back to the same issue we had at the beginning of the year. Stocks are potentially fully valued, and now I think it's more of an excuse than anything else for a decline in the market. The market's heavy. It's technically a sale right now."
The advance/decline may also be signaling that the market is overbought, according to Bespoke.
"The rally has been so strong that the 10-day advance/decline line for the S&P 500 is currently near its highest levels since at least 1990," the firm said in a note.
The A/D line measures the 10-day rolling total of the net number of advancing stocks in the S&P 500 each day. At the current level of 1,944, it is near the highest levels of the bull market, and two times in late 2009 were the only instances since 1990 that the 10-day advance/decline line has been higher than it is now.
"It's an indicator you use to gauge the short-term stance of the market," Hickey said. "When you've seen it get to these extreme levels in the short term, the next week you see below-average returns. But when you see real big surges, like we've had in the last week, it tends to be more of a positive than negative."
The line could indicate that the market is just ready to take a brief pause before resuming its move higher, he said.
(Read more: Watch out for resistance)
As for the economic data Thursday, traders will be watching unemployment claims and CPI at 8:30 a.m. Leading indicators are reported at 10 a.m., as is the Philadelphia Fed survey. Manufacturing PMI is released at 8:58 a.m.
"The problem with any economic data that gets reported for the next three weeks, is how much of it has to do with the weather, and how do you strip that out?" Massocca said. "It's kind of rendering data useless."
Earnings on Thursday including an important report from Wal-Mart, which has already said its sales were hit by a cutback in the national food stamp program and bad weather. DirecTV,Hormel Foods, Tim Hortons, TransCanada, Sonus, Imax and Federal-Mogul, also report before the bell. Hewlett-Packard, Priceline.com, Groupon, Nordstrom, Newmont Mining, Mohawk Industries, Intuit and WebMD, report after the bell.
(Read more: Natural gas soars)
There is also important energy supply data Thursday. Natural gas storage data is released at 10:30 a.m., and that will be closely watched after natural gas surged nearly 12 percent Thursday in a rally sparked by new reports of another arctic blast that will last into March.
Oil inventory data is released at 11 a.m.
—By CNBC's Patti Domm. Follow her on Twitter