1. A method of determining a forecast of wind-resources of a wind-farm, comprising: receiving a long-term data-set of meteorological data which are related to a location of the wind-farm; generating a short term data-stream having multiple dimensions by measuring wind-speeds a at a plurality of spatially distributed wind-turbines of the wind-farm and at a plurality of heights for each wind-turbine for a parameterization of an atmospheric turbulence; and generating a forecast via a numerical weather-prediction-tool by combining the data-stream with the data-set of the meteorological data in order to determine the forecast.