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Nowadays，main nowcasting techniques comprise three aspects： extrapolation forecast， numerical model forecast，and knowledgebased forecast technique. The mainstream nowcasting technique is still extrapolation forecast，which is mainly based on radar data， and use the radar echo cell tracking algorithm or radar echo area tracking algorithm to obtain the extrapolation nowcasting of precipitation echoes and rainfall. In this paper, the advances in researches and the basic principles on the three radar echo area tracking algorithms (Tracking Radar Echoes by Correlation， Optical Flow, and Variational Echo Tracker) are introduced. Based on scientific researches and operational practices，the radar echo area tracking algorithm, which is a key part of nowcasting expert system，preferably has predictability in convective weather nowcasting， and the extrapolation prediction is more closer to observation than numerical model prediction. With the continuous improvement of the algorithms， the predictability in convective weather nowcasting for all nowcasting expert systems increased. With the development of weather radar technique on both hardware and software， the quality of radar data is gradually improved. In convective weather nowcasting， the nowcasting techniques based on radar echo area tracking algorithm will highlight their obvious advantages.