Art Cashin says the stock market appears to be "off to the races, pretty clearly" after the benchmark S&P 500 stock index decisively broke above 1815, a key technical level.
About midway through today's session, the S&P was trading above 1828, a gain of more than 10 points.
But Cashin, UBS' director of floor operations at the NYSE, warned CNBC's Bob Pisani that "it is a market and things can change."
Specifically, "If we were suddenly to get a hike in the 10-year (U.S. note) yield. We're looking at 2.95 (percent) as an area of concern."
As for forecasts the stock market will score another double-digit percentage gain in 2014, Cashin thinks it will depend on whether corporate America can continue to report strong earnings.