The additional ensemble forecasts in support of the BC Optional Programme at 06 and 18 UTC were made available on 8 July 2015.

New forecast products are available at 3-hourly steps out to forecast range 144 hours (please note that there are slightly more steps than anticipated but this is necessary because of technical restriction in the coupled ocean model). All parameters and levels available for the two main cycles at 00 and 12 UTC, TYPE=CF/PF are also produced in the new additional 06 and 18 UTC runs. The new 06 and 18 UTC ENS products can be requested through the ECMWF dissemination and from MARS while available in the FDB. The data can be retrieved in the same way as the corresponding 00 and 12 UTC data sets using stream ENFO and WAEF. A special key word USE=BC is needed in the dissemination system to activate the BC specific product generation for the new additional runs. This key word is currently only applicable for the new 06 and 18 UTC runs.

The data stream id letter (third letter) in the dissemination file names is:

  • 'X' for STREAM=ENFO,USE=BC and

The production schedule for the new products will be off-set by six hours from the times for 00 and 12 UTC runs:

  • 00 UTC based products start becoming available at 07:40 to 08:04
  • 06 UTC based products start becoming available at 13:40 to 14:04 - NEW
  • 12 UTC based products start becoming available at 19:40 to 20:04
  • 18 UTC based products start becoming available at 01:40 to 02:04 - NEW

BC Programme members can request new products the standard way using the usual procedures at

There is currently only limited temporal storage in MARS for these products in line with the archive data available for 00 and 12 UTC, and no model levels are archived for the perturbed forecasts. Model level data can only be retrieved from MARS while the data is still available in the FDB, which is usually for up to two days for all four ENS cycles. A solution for a temporary storage for model levels for all four ENS runs is planned for later this year.

We encourage you to use the new datasets and welcome your feedback via e-mail to