REFS = Rapid Refresh Ensemble Forecast System. Still experimental, but under intense fine-tuning development in 2025. Forecasts are hourly out to 60 hours.
This ensemble model (group of models) is derived from time-lapsed versions of RRFS (and some HRRR input? ) and runs every 6 hours at 00z 06z 12z and 18z. Forecasts are hourly out to 60 hours.
- On-Time Members: Typically, 5 ensemble members are initialized at the current forecast cycle time.
- Time-Lagged Members: To enhance ensemble diversity without additional computational cost, 5 members from the previous forecast cycle (e.g., 12 hours earlier) are incorporated.
- Total Ensemble Members: 12 (5 on-time + 5 time-lagged and 2 HRRR)
- Initial Conditions: Derived from RRFS Ensemble Kalman Filter (EnKF) analyses
- Lateral Boundaries: From Global Ensemble Forecast System (GEFS) members
- Dynamical Core: Unified Forecast System (UFS) Finite-Volume Cubed-Sphere (FV3) for all members
- Stochastic Physics: Includes Stochastically Perturbed Parameterizations (SPP) (*) and fixed perturbations (#)
Due to the fact that the experimental version is running on less robust supercomputers, each 6 hour model run is processed and completed about 7 hours later.
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