Plot a raw time series together with it's fitted curve and add forecasts and prediction intervals to the end.
forecastplot(x, ...)iNZightTS object
additional arguments passed on
Called for the side effect of drawing a plot.
The constructed ggplot object is returned invisibly.
The predictions and prediction intervals are the result of models
fitted by the Holt-Winters method. The amount of predicted
observations is calculated by 2 * freq, where freq is
the frequency of the time series object.