how can you roughly predict future volatility in short term? I mean beside news calendar, is there any methods or tools to identify which currency pair would be volatile for example tomorrow, next 3 days or next week? From my experience, i do this by calculating the average daily/weekly range, but works not ideal in real trading. Very thanks if someone can share better ideas.
Well, my understanding of Bollinger Bands is that when they're very close together (low volatility) for a while there is an increased probability for some sort of move, breakout, or what have you.
Look up "Bollinger Squeeze" on Investopedia. That may give you a starting point.