The stock market next year could peak at heights that are double-digit percentage points above current levels, according to BMO Capital Markets.

"If we learned one thing in 2018, it's that change is going to be constant and volatility is going to reign supreme for the next couple of years," BMO Chief Investment Strategist Brian Belski told CNBC on Monday.

However, in a research note Friday, BMO said, "U.S. stock volatility in recent months and changing leadership trends in no way alter our longer term secular bull market stance."

In fact, under BMO's "base" case next year, the would "grind higher" and hit 3,150, about a 15 percent rise from Friday's close. BMO's "bull" case, which depends on strong-than-expected economic growth, predicts 3,400 on the index, about a 24 percent increase.

BMO also modeled for a possible stall in fundamental momentum and economic activity, warning its "bear" scenario could take the S&P 500 down to 2,500 next year, about an 8.6 percent decline.

In the meantime, Belski thinks the recent market rout presents a once-in-a-generation buying opportunity in financial stocks, "given the fact that we believe the majority of investors absolutely, positively hate financials." He said BMO remains overweight in companies with "scalable business models" such as Bank of America, Morgan Stanley and Goldman Sachs.

Belski said BMO also likes technology, the former leader of the market's march to record highs earlier this year. It can pay to be a "little contrarian," he said, advising investors to look to companies with "stable earnings" like Apple, Microsoft and Oracle.

Plummeting tech stocks pushed the Nasdaq further into correction territory last week and during Monday's trading day. While under pressure, the Dow Jones Industrial Average and S&P 500 remained above the down-10-percent-from-record-highs threshold for a correction.