Implemented: 11 March 2008  

Datasets affected

  • HRES
  • ENS




Atmospheric (unchanged)
  • HRES: TL799
  • ENS: Leg A TL399
Wave (unchanged)
  • HRES: 0.25 degrees
  • ENS: 0.5 degrees
  • LAW: 0.1 degrees

Atmospheric (unchanged)
  • HRES: L91
  • ENS: L62

Meteorological content

  • Use of persisted SST anomalies in all atmospheric forecasts
  • Daily ocean-coupling of days 10 to 15 of 0000 UTC ENS forecasts
  • Modified EFI products using the new unified re-forecasts

Meteorological impact

Previously, the sea surface temperatures were persisted from the initial conditions during both the deterministic and the medium-range ENS forecasts. With the implementation of the unified VarEPS monthly system, the sea surface temperature anomalies relative to the 1979-2001 ERA-40 daily climates are persisted. The anomalies are added to the ERA-40 daily climate to produce the full SST field.

Technical content

  • Monthly Forecast run once per week from 0000 UTC on a Thursday as an extension of the 15 day ENS forecast from this base time 
  • New GRIB description for all Monthly Forecast products, analogous to the current medium-range ENS data

Model ID

  • Atmospheric: 131
  • Ocean wave: 116
  • Limited-area ocean wave: 216