Description of the upgrade

The IFS Cycle 49r1, will bring major changes to the IFS model and data assimilation system, including among many others:

  • assimilation of 2m temperature observations, 
  • Land-surface model updates,
  • increased resolution and soft-recentering of the ensemble of data assimilations (EDA)  and
  • activation of the stochastically perturbed parameterisations (SPP) model uncertainty scheme in all ensemble configurations. 

The re-forecast systems for medium and extended range will see the change in frequency, both will run over past 20 years, on the fixed days of the month: 

  • medium range every four days: 1/5/9/13/17/21/25/29 (excluding 29 February)
  • extended range every two days: 1/3/5/7/9/11/13/15/17/19/21/23/25/27/29/31 (excluding 29 February)

The resolution of the wave model will change to 9km (Tco1279) grid in the medium range and 36 km (Tco319) in the extended range, to match the atmospheric model.

More detailed information will be available in the coming weeks.

For any questions, please contact us via the ECMWF Support Portal .

Cycle 49r1 will be implemented Q4 2024

#IFS49r1 #newfcsystem @ECMWF


  Initial announcement.

Initial announcement.


Introduction to Cycle 49r1Verification, products and technical aspectsData access and format, testing and practicalities

Coming soon! Watch this space!

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