Flood Alert System Using High-Resolution Radar Rainfall Data: Nowcasting Model Movement and Reflectivity Analysis 1 , 2

Abstract

There are many methods for forecasting with longer lead-time of 8, 24, and 36 hours or weekly, using autoregressive methods, moving averages and others. However, the study is a special kind of Nowcasting method for shorter lead-time in minutes. In the western Puerto Rico, sudden precipitations occur with short durations due to atmospheric conditions and topographic features at a given location. Precipitation events may develop, occur and dissipate immediately, with its duration of about 1, 2 or 3 hours. Knowing the precipitation characteristics, the nowcasting model developed in the research only needs two lag times for prediction. This means that the model has the capacity to forecast the rainfall even if the duration is very short. The developed model is presenting the best prediction when the lead-time is 10 minutes. The postulated rainfall nowcasting algorithm involves two major tasks: predicting the future location of the rain pixels, and predicting rainfall at each pixel.