Stock-market guru Jeremy Siegel, professor of finance at the University of Pennsylvania, predicts that stocks

"Once this storm passes, I think the fourth quarter could be very good," Siegel, a Wharton School finance professor, told CNBC.

Siegel cautioned that August and September typically yield choppy trading and may not provide the best reflection of stock-market health.

To be sure, the Dow Jones industrial average tumbled 1,000 points minutes after the market opened in a wave of selling that circled the globe after a historic plunge in Chinese stocks.

Though the declines eased significantly as the morning went on, it sent a shiver of fear through Americans with retirement accounts or saving to buy a home that the bull market is over, the AP reported.

The Dow fell 1,089 points within the first four minutes of trading as traders dumped shares. But the fire sale was short-lived. A wave buying cut the Dow's losses by half just five minutes later.

But the noted bull took a less optimistic tone on a previous call that the Dow could reach 20,000 this year. However, he contended the index, which has fallen nearly 9 percent this year, could still turn positive by the end of 2015, CNBC reported.

"I still think we're going to be up for the year, and 19,000 is not at all impossible," Siegel added.

Newsmax Finance Insider Hans Parisis cautions investors to stay patient - and to think for themselves.

“Long-term investors should, at least in my opinion, try to remain patient and certainly shouldn't follow the herd,” Parisis wrote.

(Newsmax Wire Services contributed to this report).

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