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The strategies of the extrapolation adjusted by model prediction (ExAMP) blending scheme, which trusts the field pattern predicted by extrapolation and allows the field intensity to be adjusted by numerical weather prediction (NWP), for rainfall nowcasting are analyzed in this study. The McGill algorithm for precipitation nowcasting by Lagrangian extrapolation (MAPLE) and the Weather Research and Forecasting (WRF) model serve as the extrapolation and NWP models, respectively. Seven 150-min rainfall nowcasting experiments with different strategies are carried out for 37 sampled periods from seven heavy rainfall events in Taiwan in 2019. The results of the overall statistics indicate that, for the extrapolation component, extrapolating the current rainfall rate estimated from the lowest dual-polarimetric radar observations is a superior strategy. The ExAMP scheme that blends the MAPLE and WRF forecasts can surpass both components in 150-min rainfall nowcasting, and an empirical limitation on the innovation of intensity during the blending procedure is found unnecessary in this study. Moreover, the spatial performance for two contrasting events reveals the ability of ExAMP in grasping the rainfall strengthening and weakening in different areas. The skill statistics separately at rainfall strengthening gauges and weakening gauges further prove the effectiveness of ExAMP even though it is effective in intensity correction instead of pattern correction.

Toward the understanding of rapid intensification (RI) of tropical cyclones (TCs) in the western North Pacific, the TC's deep convective cloud (DCC), precipitation, and cloud properties in terms of cloud effective radius, optical thickness, and top height from satellite observations are investigated. Mean and radial distributions of the variables at different intensity stages and intensification categories are examined. The relationship indicates that the DCC percentage and temperature, especially their radial distributions, could be used to identify an impending RI regardless of TC intensity. Meanwhile, the mean and radial distribution of precipitation may discriminate RI from non‐RI in tropical depression (TD) and tropical storm (TS). The radial distribution of the cloud properties in rapidly intensifying TD and TS also suggest that most of the clouds near the center of the storm has deepened already while those that are far from the center are generally in developing or dissipating stage. Moreover, rapidly intensifying TCs, regardless of their intensities, manifest common DCC, precipitation, and cloud properties characteristics near the TC center. It is to be noted that the different mean and radial distribution characteristics of the variables between initial and continuing stages of RI are inferred to be artifacts of their intensities and RI rates (or radius of maximum wind sizes) rather than whether the TCs are at the onset or 24 hr of RI. We want to know if there are unique features of deep convective cloud (DCC), rain, and cloud properties that can be used to predict the rapid intensification (RI) of a tropical cyclone. RI can be predicted using DCC in all storm categories. Precipitation is also useful in anticipating RI but for weaker storms only. The deep convection, rain, and cloud properties near the center of rapidly intensifying storms suggests that clouds within that region has deepened already as compared to the clouds that far away from the center. All storms that are rapidly intensifying share the same DCC, rain, and cloud properties characteristics near the center. The different characteristics observed at the beginning and at 24 hr of RI are more related to their intensities and intensification rates (or the size of their radii of maximum wind). Deep convective cloud's (DCC's) radial distribution can identify an impending rapid intensification (RI), whereas precipitation can be used to anticipate RI in weak tropical cyclones (TCs)RI TCs, regardless of their intensities, have common DCC, precipitation, and cloud properties characteristics at the TC centerCharacteristics found in initial and continuing RI are artifacts of their intensities and RI rates (or radius of maximum wind sizes) Deep convective cloud's (DCC's) radial distribution can identify an impending rapid intensification (RI), whereas precipitation can be used to anticipate RI in weak tropical cyclones (TCs) RI TCs, regardless of their intensities, have common DCC, precipitation, and cloud properties characteristics at the TC center Characteristics found in initial and continuing RI are artifacts of their intensities and RI rates (or radius of maximum wind sizes)