The Standard & Poor's 500 Index already has risen 176 percent from its March 2009 low, but that doesn't mean the fun has ended yet, says Liz Ann Sonders, chief investment strategist at Charles Schwab.

"I think what started five years ago was the beginning of a secular bull market, not just a cyclical bull within an ongoing bear," she tells Yahoo.

The market's recent rally, which took the S&P 500 to a record Monday, stems from positive views about the economy rather than negative views accompanied by expectations that the Federal Reserve will pull back on its tapering of bond purchases, Sonders says.

Editor’s Note: Retire 10 Years Earlier With These 4 Stocks

Bad weather largely explains recent weak economic data, she maintains. "There is a lot of indication that this has been very dependent on the weather, but I also think we're well past the point where the market is going to rally on negative news."

However, the longer the weather impacts the economic data, the less output is recovered, she argues.

"The question is how much of the lost output gets made up. If you look at the history of lengthy periods of weather-hit economies, it tends to be about a 75 percent to 80 percent recovery in the next quarter or two from the pent-up demand from the lost output."

As for the Fed, "I think the market wants to see tapering," Sonders notes. "I think it wants to see monetary policy move toward normalization, and we are well past the point where a Fed having to open up the bazooka again would be good for the market."

Tom Lee, chief equity strategist at JPMorgan Chase, also thinks stocks have more room to rise, helped by pent-up demand, crumbling infrastructure and record amounts of consumer wealth.

"To me it's really a formula for stocks to do quite well because it's going to be a story about earnings surprise for the next few years," he tells CNBC.

"I still think we're just in the middle innings of a bull market."

Editor’s Note: Retire 10 Years Earlier With These 4 Stocks

Related Stories:

• Haverford's Smith: 'We Are Only Halfway Into This Secular Bull Market'
• Surprisingly Strong Corporate Sales Underpin Bull Market