A new scheme is developed to retrieve three dimensional wind and thermodynamic field using 3dVar techniques in which all retrieved variables are expressed by three-dimensional extensions of Legendre polynomials. The three movement equations, continue equation and boundary conditions are used as weak constraints in the costfunction. This scheme uses two volume scans from each of the two radars to retrieve the wind fields at the beginning and ending times and the perturbation pressure and temperature fields at the middle time of the volume scans in three-dimensional space. During the retrieval period, the retrieved wind field is linearly interpolated in time to fit the observed radial winds at the time of each scan elevation (or each beam position). This treatment is found to be useful in improving the accuracy of the retrievals. The scheme is tested with the simulated data for a supercell storm with very encouraging results. The scheme is also being tested with NEXRAD data. The details will be presented at the conference.