If the equity ally out of mid-July were a movie, Hollywood might call it "Uncle Buck," as it has been all about the U.S. dollar rebounding from a 30-year slide.

And now both dollar and stock rallies look set to continue, with longtime bears over at brokerage Goldman Sachs (GS) announcing that they think the U.S. currency has embarked on a significant advance.

They don't think that the greenback is improving because traders are so confident in the U.S. economy; however, but because growth in every other region of the world is growing worse. (See also: "Are Global Markets Headed for a Plunge?")

Goldman says traders are looking at rapidly slowing economic activity in the UK, Scandinavia, Australia, New Zealand and Canada and thinking the barely positive results in America may not be so bad.

The Wall Street Journal points out that gross domestic product in the euro zone contracted 0.2% in the second quarter. It was the first time since the early '90s that the 15 countries using the euro had seen a joint contraction. That's a big deal. No wonder oil and other raw material prices are falling off a cliff.

You may have noticed that gold is off 20% from its high last year, but did you know that silver, which has more industrial uses, is off 32%?

Many of the shares of top silver miners have been annihilated, with Apex Silver (SIL) down 80% since October, to $3.38 from $21.33. Big U.S. silver miner Coeur d'Alene (CDE) is down to $1.89 from $5.80 since March alone!

This global weakness has been a shocker to folks who thought that Europe and other countries had strong internal economies that would insulate them from U.S. recessionary trends, as the term "decouple" became a buzzword. So much for that idea.

The giant Brazilian miner Vale do Rio Doce (RIO) has seen shares plunge 45% since May. British super-miner Rio Tinto (RTP) is down 37% since May.

Australian super-miner BHP Billiton (BHP) is down 34%. So as you can see, it's not one region, it's a conflagration of value throughout the commodity industry.

While some of these stocks have had similar decline in the past few years, they have always recovered more quickly. As a result, they are all now trading below their 12-month average for the first time since 2003, pushing them into the sort of bear-market territory from which it is much more difficult to recover.

If you are hanging on to any of these big commodity stocks in hopes that they will rebound soon…