The Upper Air Derivative Data from NMC Data Set was derived from National Meteorological Center global upper air models. These models use a 6 hours intermittent assimilation method. In this method, the objective analysis is performed every 6 hours using a 6 hours forecast as an initial guess (Kanamitsu 1989). The National Meteorological Center (NMC) gridded upper air data was extracted from the NOAA operational analysis system and transmitted to the FIS. This contained spatially interpolated NMC upper air data calculated for four grid points of 381 km polar-stereograph over the FIFE area. FIS considers this a derived data set (i.e., not from original measurements).