Traders watching these clues for a market breakout

"We've been caught in a sideways range and we're probably going to stay here until we get more clarity on the Fed," said John Caruso, senior market strategist at RJO Futures.

"I'll just be watching key resistance levels tomorrow," he said. He's watching to see if the S&P 500 can top 2,164 and then 2,174, before retesting its record close of around 2,190.

The area between 2,175 and 2,180 is a significant indicator on whether the S&P 500 can break higher, according to John Kosar, chief market strategist at Asbury Research. On the downside, he's watching 2,142 as support.

"Traders feel safe inside these parameters," he said. "Once you get outside the parameters, you're taking a directional bet for the very near term."

In that short-term outlook, oil prices will likely play a major role in driving stock market performance. U.S. stocks closed higher Monday as U.S. crude oil futures rose 3.09 percent to settle at $51.35 a barrel, the highest since July 2015. Intraday, WTI hit $51.60 a barrel, its highest since June 9, 2016.

The gains came after Russia said it was ready to join the Organization of the Petroleum Exporting Countries in limiting production.

"So far it's just words, and the same goes for OPEC," said Luana Siegfried, energy research associate at Raymond James. She said she wants to see actual figures on whether oil production comes down after such an agreement, but that she expects oil to reach $60 by the end of the year regardless.