The program RAWINS performs an objective analysis by blending the first guess fields generated by REGRID with upper-air and surface observations. There are four objective analysis techniques available in RAWINS: circular-shaped (Cressman) weighting function, elliptical-shaped weighting function, banana-shaped weighting function, and multi-quadric interpolation. In addition, RAWINS performs some data quality checks against user-defined thresholds. The objective analysis is performed for a user-defined number of pressure surfaces (generally mandatory levels plus some additional surfaces). RAWINS is also used to prepare the analyses for the analysis nudging in the forecast model (see Section 4.6.6). RAWINS is described in Manning and Haagenson [1992].