The use of real-time observations has always been extremely important for the forecasters at the Storm Prediction Center (SPC). Various systems have been in place at the SPC for over 15 years to objectively analyze the surface data and calculate selected thermodynamic fields. However, a new system has been developed that provides an hourly three-dimensional objective analysis of the atmosphere. Calculations of a much wider range of fields are now possible, including kinematic and shear parameters used for forecasting severe thunderstorms as well as winter weather forecasting parameters, and key fire weather fields.

The new scheme has been designed to assimilate the various real-time observational datasets that flow into the SPC. The hourly forecast runs of the 40km RUC with 25mb vertical resolution are used as first guess fields for the contiguous United States. The input datasets include surface observations, wind profilers, WSR-88D VAD wind data, Oklahoma mesonet data, etc. A robust set of diagnostic and sounding analysis routines are then used to compute over 200 parameters used by operational forecasters to diagnose various forms of hazardous weather.

This innovative system has been in use at the SPC for nearly three years, and has become the primary method of real-time data assimilation and objective analysis at the center. Applications to the prediction of severe storms events are presented using several case study examples.