A pause in the rally could be coming, says one strategist, who adds that this downturn could be a prime buying opportunity for investors.

Other analysts on Wall Street have called for more market volatility in the coming months thanks to political uncertainty in the U.S. and Europe. However, Stephen Parker, head of thematic solutions at J.P. Morgan Private Bank, believes investors shouldn't panic.

"What we're telling clients is, 'be patient right now,'" he said last week on CNBC's "Futures Now." He added: "We may see some volatility, but if you do see a pullback in markets, that's more an opportunity to buy than a reason to think that this rally is over."

According to Parker, while pro-business policy out of Washington could drive stocks higher, the bull case ultimately hinges on what he sees as improving global growth, and the potential for stronger earnings for the rest of the year.

"You're starting to see that translate into a positive momentum on the earnings front," Parker explained, adding that the move was bigger than the "secular growth" sectors like technology and health care.

Those "have led over recent years, but really the more cyclical parts of the market like banks and energy," are also showing strength, he added.

These same cyclical sectors, said Parker, are "really leveraged to an improving U.S. and global growth story" and will ultimately provide "tailwinds" for markets to move higher regardless of what happens in D.C.

This means that while investors may be looking for the trade and tax policies promised by Trump in his presidential campaign, Parker actually sees market fundamentals as the lead cause for why stocks will "grind higher" this year.

Markets did sell off last week as a result of Trump's failed health care bill, but all three major indexes had regained those losses by the end of the week.

Parker sees the S&P 500 Index running up another 3 percent higher by year-end, though he stresses that that's only the "base case" for stocks, with policy changes and stronger market fundamentals potentially driving stocks even higher.