I am trying to forecast hourly wind speed (HWS) data in Trinidad and Tobago and I have read in the literature that "Direct application of stochastic models (ARMA & ARIMA models) to HWS series is not possible due to their non- Gaussian distribution. To resolve this problem, and with the aim of simulating HAWS, Daniel and Chen (1991) have proposed a transformation of HAWS using the Dubey method (1967). In fact, Dubey showed that, for shape parameters close to 3.6, the Weibull distribution has a shape similar to the Gaussian one. This approach is reasonable because a Weibull random variable to the power of x is also a Weibull random variable." the review says that x=k/3.6 where k is the form factor of the weibull distribution of the observed hourly wind speed.
Can anybody assist me in how to go about this? My data is hourly wind speeds for 7 years, so how do I determine k?