Selected Cases of the RSM-based NCEP Short-Range Ensemble Forecasting (SREF)

Case 3: Short Wave System at 500mb Level

This case (12Z, 02/28/97) shows that a simple ensemble averaging process can reduce the forecast (48hr) position of a short wave (trough) at 500mb level from about 900km (Fig. CTL, control forecast) to about 400km (Fig. Mean_r, ensemble mean) comparing to its analysed position (Fig. ANL). The ensemble mean was calcualted from a 5-member RSM-based ensemble (with regional bred mode).