Overall, the U.S. dollar has rallied this year, with the Dollar Index (DXY) now up by roughly 8 percent year-to-date, according to Bloomberg data. But the gain hasn’t been steady. Instead, the dollar has been on a rocky ride, as investors have repeatedly re-calibrated their expectations for U.S. growth and the timing of a Federal Reserve (Fed) rate hike.

Indeed, world currency markets have roared back to life lately after years of hibernation, with a handful of monetary policy surprises-including the European Central Bank (ECB)’s bigger-than-expected bond buying program and the Federal Reserve (Fed)’s delay in raising rates-leading to rising volatility , as the chart below shows. This begs the question: Where will the dollar go from here?

FX Volatility – CVX

My answer: Though currency market volatility is likely to continue, I still see a stronger dollar over the longer term. Here’s why:

Diverging central bank policies

As the U.S. economy continues to modestly strengthen, the Fed will likely begin raising rates later this year, and possibly as early as September. In fact, in her recent testimony before Congress, Fed Chair Janet Yellen laid out a fairly upbeat assessment of the U.S. economy and left the door open for a September rate hike. While the U.S. tightens, most other central banks will likely remain in easing mode. (For more on this monetary policy divergence, check out the BlackRock Investment Institute “Diverging World” interactive graphic ).

The U.S. energy renaissance

As the U.S. has become more energy independent, we’ve had to import less from overseas. Over the last 10 years, the U.S. current account deficit has been cut roughly in half, and a large part of that improvement has been a function of surging U.S. domestic oil production. Looking forward, rising U.S. production should continue to support a strong dollar.

U.S. dollar rallies have tended to last years, not months