Enhanced short-range forecasting of sub-inversion cloudiness in complex terrain

Accurate spatial and temporal forecasts of fog and low cloud occurrence are still a challenging research topic due to the complexity of its physics. In the nowcasting range, observation-based techniques are often superior to numerical weather prediction (NWP) models and provide useful guidelines for operational forecasters. This article proposes a low stratus nowcasting scheme which merges station measurements, satellite data, a nowcasting technique and NWP data at a very high horizontal resolution (1km). Case studies and a comprehensive validation over Austria reveal that the proposed approach of parameterizing sub-inversion cloudiness adds value especially in complex terrain and even for longer lead times due to the dynamic design of the method.