THE ISAAC EFFECT: Prices for wheat, corn and soybeans rose. That was partly from Hurricane Isaac. Its rain might be welcome after a drought, but it's unlikely to have much effect on crops that have been suffering all summer. It will also cut into harvesting time in the Southeast.

THE ISAAC EFFECT, PART 2: Oil prices fell, despite Isaac's forcing some Gulf Coast rigs to temporarily shut down. Investors seemed more swayed by a government report that inventories of crude oil rose last week for the first time in a month.

NOT-HEAVY METALS: Major metals all fell slightly. Precious metals like gold and silver were down, and so were industrial metals like copper and palladium.