"This is an environment where you're going to see a lot of volatility based on small details." The dollar index, which measures the greenback against six counterparts including the yen and euro, rose 0.4% to 105.56, taking its weekly gain to more than 2% and putting it on track for its best one-week performance since late September. According to a Reuters survey of economists, the non-farm payrolls report is expected to show on Friday that 200,000 jobs were created in December, easing from November's 263,000 pace but still about double the level the Fed considers sustainable.