Precipitation at higher latitudes will be investigated using data from both active and passive microwave remote sensing instruments. A 1-D parametric precipitation model and physically-based microphysical representations of ice particle size distributions and microwave scattering properties, together with a fast radiative transfer model and a radar beam model, will produce simulated upwelling microwave brightness temperatures and radar reflectivities in native observation space. This forward model - combined with concurrent Advanced Scanning Microwave Radiometer (AMSR-E) and ground-based radar observations from the Baltic Sea region - will be used within an optimal estimation framework to exhaustively study higher latitude precipitation events. We anticipate that the combination of ground-based active and satellite-based passive microwave observations in a consistent physical framework will provide more information content about the vertical structure of hydrometeors in precipitating weather systems than just considering either one alone. We will attempt to quantify this additional information content and exploit it to gain new insights into high latitude precipitation. We will also test the sensitivity of various precipitation model parameters to highlight what parameters are most important in producing microwave signatures of observed radar and satellite data in precipitating higher latitude weather systems, and thus develop further constraints on the precipitation model parameters. Lastly, independent data from the CloudSat satellite will be used to evaluate the profiles of precipitation generated by the 1-D precipitation model. Information gained from this research will be invaluable to current and future planned missions to investigate global precipitation using passive microwave instruments.