Invesco market watcher Kristina Hooper believes Wall Street should brace for trouble.

"We could see another about 10 percent sell-off, and it could happen relatively quickly or it could be a bit more gradual this time – sort of death by a thousand slashes potentially this fall," the firm's chief global market strategist said Tuesday on CNBC's "Futures Now." "I wouldn’t be surprised to see a significant sell-off in the second half."

Hooper cites too much buoyancy in the stock market, as well as ominous results from a recent Invesco survey that showed retail investors are becoming more confused and should be viewed as a flight risk.

"They were rattled by that first-quarter sell-off," she said. "We do have to be prepared for the fact that investors may want to run for the exits."

The study, which Invesco commissioned through global market research institute GfK, surveyed more than 800 advisors and 1,015 investors in both January and April. The objective was to compare the sentiment of individual investors to advisors.

The outcome: Investors were overwhelmed while the professionals had a steadier hand.

Hooper believes not even a strong earnings season, which kicks off this Friday, can singularly prevent a second-half correction.

"You do have protectionist concerns and actually protectionist actions also combined with continued Fed tightening. That could create something of a perfect storm," Hooper said.

Despite her warning, Hooper doesn't expect the to permanently shed gains for 2018. Her year-end price target is 2,850 to 2,950, which represents a 2 to 5 percent gain from current levels.