The Dow Jones industrial average was up 212.67 points, or 1.85 percent, for the day at 11,715.18.
The Nasdaq composite rose 29.18, or 1.22 percent, at 2,411.64. The Standard & Poor 500 was up 19.02, or 1.48 percent, at 1,300.68.
Crude oil prices, which had advanced most of the week as Tropical Storm Gustav headed toward the Gulf of Mexico, suddenly suffered a turnaround Thursday and began losing. Crude dropped $2.40 to fall to $115.75 per barrel, affected somewhat by a big natural gas sell-off.
Meanwhile, oil companies began moving personnel out of the gulf and preparing for the worst.
Treasury prices fell. The benchmark 10-year shed 8/32 to yield 3.795 percent.
The dollar was mixed. The euro recently fell to $1.4688, compared to $1.4722 late Wednesday. Against the Japanese currency, the dollar recently fell to $109.59 yen, down from $109.61 yen.
Overseas, Tokyo's Nikkei 225 closed flat at 12,768.25 and London's FTSE 100 fell 0.24 percent to 5,514.90.
Meanwhile, the U,S, Commerce Department said in a report that the economy grew in the second quarter at a 3.3 percent annual rate. That's almost double the 1.9 rate in the government's first report on the period's growth.