NEW YORK (TheStreet) -- Brace yourselves: The dollar is set to surge once again.

That's because while there are questions about the strength of the U.S. economy, there's no question that the rest of the world is in an even worse state.

Investors should expect the  PowerShares DB US Dollar Bullish (UUP) - Get Report  exchange-traded fund to follow the dollar higher. It holds a basket of futures contracts designed to track the strength of the greenback against major world currencies such as the euro, Japanese yen and Great Britain's pound.

The dollar index, which measures the strength of the greenback against a traded-weighted basket of major currencies, dramatically appreciated starting in July 2014, rising approximately 23% by March 2015, at which point it paused. Since then the value of the index has moved broadly sideways, fluctuating month-to-month.

The difference between the health of the United States economy versus the rest of the world is the reason the dollar will resume its upward trajectory. That relative strength means the Federal Reserve will very likely start raising the cost of borrowing before the central banks of the other major economies, such as the European Central Bank or the Bank of Japan.

It's what Win Thin, global head of emerging market currency strategy at Brown Brothers Harriman, calls "divergence in monetary policy." Or put another way, when the Fed moves, most other central banks will not.

Investors allocate capital to where they can get the best returns. So when interest rates increase in one country versus another, then the money flows to where it gets the higher rate.

It increasingly looks like the Fed will be first off the starting blocks with other countries not following suit, and in some cases actually cutting their lending rates. 

The recent economic pulse from the rest of the world looks, well, dodgy. 

GDP growth in China fell to 6.9% in the third quarter, according to the latest data. It's the slowest growth since the financial crisis. While that number looks nominally high, the data isn't very transparent and investors are better off looking at the direction. In this case, the Chinese economy, the world's second-largest, is slowing down, which tells you things are not well.

"Chinese industry and resource demand remains weak," Bill Adams, senior international economist at PNC Financial Services, wrote in a recent report. He also points out that growth of investment in so-called fixed assets, such as factories and machinery, was "its weakest in 15-years.

The weakness in China's industrial sector has had a knock-on effect for those countries that rely on the sales of natural resources to sustain themselves. Both Australia and Brazil have had a tough time since China reduced its appetite for iron ore and coal. Likewise, Canada has suffered from falling global prices for energy and minerals.

In the eurozone, things don't look very cheery either. A recent report by BBH notes that the European Central Bank's money-printing program "could be extended, expanded, and/or its composition changed." The so-called asset purchase program has tended to depress the value of the euro versus other major currencies like the dollar.

Likewise, Kurt Karl, chief economist at insurance giant Swiss Re, sees little danger of the Bank of Japan raising rates. It economy has stagnated for almost two decades, though Prime Minister Shinzo Abe is working to return it to growth through higher government spending and deregulation of business.

There is likely one significant exception to the monetary divergence. The Bank of England, like the Fed, is getting set to raise the cost of borrowing. That said, it seems unlikely that the British central bank will move before the Fed does so.

This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.