The implied volatility indexes covered here already serve precisely the function you describe. They state an annualized 30-day implied volatility (forward-looking) for the asset in question, within one standard deviation.
VXV, one of the components in my VIX Premium Ratio, tracks a similar three month estimate for the S&P 500.
Monday Equity Volatility Report [View article]
VXV, one of the components in my VIX Premium Ratio, tracks a similar three month estimate for the S&P 500.