To enhance ground-based observations for continental warm clouds, we introduce a novel retrieval method that exploits the previously untapped solar background signal present in current lidar measurements. We will demonstrate how this new method greatly extends lidar applications from cirrus to optically thick stratiform clouds. Using a three-year dataset over the Atmospheric Radiation Measurement Oklahoma site, we compare and contrast the relationships between optical depth and effective radius for both drizzling and non-drizzling clouds. This intercomparison is further used to develop a new approach for diagnosing the presence of drizzle. This new retrieval method can be easily applied to the existing lidar and European ceilometer networks.