Nowcasting

This chapter focuses on the nowcasting of convective storms and associated hazards. The nowcast process begins when the forecaster first assesses the synoptic and mesoscale weather pattern, and continues to evolve, ideally, with continuous monitoring of the local high-resolution observations. The chapter presents general methods and tools used for convective storm nowcasting in the international forecasting community. Some of the techniques and examples are taken from regions outside of West Africa, but the principles and procedures for nowcasting remain the same regardless of geographical location. The chapter discusses the nowcast process and describes the required activities for the on-duty nowcaster. This discussion also provides a background to the science behind the steps in the nowcasting process. The chapter finally gives guidelines and examples for operational nowcasting and amending terminal aerodrome forecasts (TAFs).