Started from T12Z of January 09 2001, extended T126 run from 60 hours to 84 hours for all members which include 20 pertubation and control run. Ensemble post job has included z850 field since this time.

Started from T12Z of June 27 2000, increased all ensemble T62 resolution to T126 resolution upto 60 hours.

Started from T12Z of May 10 2000, increased ensemble T12Z perturbations from 2 pairs to 5 pairs.

Before 1999: There are total 17 ensemble members in 24-hour cycle, 10 ( 5 pairs ) pertubation runs from T00Z plus GFS (high resolution deterministic forecast) and ensemble control. 4 ( 2 pairs ) pertubation runs from T12Z plus AVN (high resolution deterministic forecast) extension run.