This week could see a lot of volatility off the back of last week news. The data that is coming out of note could have adverse effects on the US and Japanese markets as well as global markets in general. Japanese retail sales come out early in the week which will shed some light on the effects of 'Abenomics' on the consumer in the past month. Bad news coming out of retail sales could put doubts into the minds of investors that a recovery is n the making and the rising interest rates could be seen as a hindrance to that, putting into question the aggressiveness of the stimulus (a bit exaggerated from one number but the idea will only be confirmed should more negative data come out).
US GDP is expected to come out around 2.5% which could continue the rally in the US should this meet (or exceed) expectations, however it could bring about concerns about the Fed slowing down purchases as well; good for the dollar, potentially bad for stocks.
The biggest factor to watch out for is Chinese PMI at the end of the week. Slowing growth in China was a major factor in the volatility in the markets last week and could be a deciding factor in the following week as well. Perhaps this is the last calm week (relatively) we will see in awhile.