The S&P 500 is set to decline over the next two weeks and could fall below 1,109 points, Carol Harmer, director of Charmer Charts, told CNBC Wednesday.
"I do think we're going to break this uptrend at 1,151 (points) and I do think we're going to go quite a bit lower in the short term, which is the next one to two weeks," Harmer said.
"We're looking at 1,126 down to 1,109 and I think it's even going lower," she said.
The S&P closed at 1,165.90 points Tuesday after seeing sharp declines during the session. But the index has made strong gains throughout most of October and September.
"If you look at the monthly chart on the S&P, I don't think anyone is going to say: 'god this is a bullish market'; it just isn't. What we've been seeing is the correction to a downtrend," Harmer said.
If the S&P rallies up to 1,175 points then investors should be positioning their portfolios for declines, she said.
"We've exhausted the upside, it tried four times to break 1,180, failed. It has to come lower," Harmer added.
Meanwhile, the euro is likely to fall toward $1.35 or lower, but that level could prove to be a base, according to Harmer.