Abstract:Using radar echo extrapolation method of the GRAPES based Severe Weather integrated Forecasting Tools (GRAPES SWIFT) of the nowcast system, the 0-1 h ahead extrapolation and forecast are made for the radar products such as reflectivity factor，echo peak and vertical accumulated liquid water content in three cases of severe convective storms, and we try to forecast the severe convection weather early warning area by comparing with the forecast outcome of the radar data to the threshold. The data come from the radar products derived from the CINRAD SB radar based data which were processed by PRG algorithm. The method is based on the TREC algorithm to get the moving forecast of radar echoes. The result shows that radar products such as 3 km CAPPI reflectivity factor， echo peak and vertical accumulated liquid water content are approximately coincident with the actuality, which can forecast the shape, change trend and moving direction of the echo, and the range, location and intensity center of the echo are similar to the actuality. The shorter the time of extrapolation is, the better the forecast is. The extrapolated radar echo from the TREC Algorithm is available within 0-1 h, and the forecast to the convection weather early warning area by the extrapolated result which gets through making up the threshold is also feasible, and they all can be used for the severe convective storm nowcasting.