Advancing global NWP through international collaboration

High resolution mean sea level pressure and ensemble spread

Saturday 20 January, 00 UTC T+96 Valid: Wednesday 24 January, 00 UTC

Ensemble forecasts explained
One 'ensemble forecast' consists of 51 separate forecasts made by the same computer model, all activated from the same starting time. The starting conditions for each member of the ensemble are slightly different, and physical parameter values used also differ slightly. The differences between these ensemble members tend to grow as the forecasts progress, that is as the forecast lead time increases.

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Wildfire, card format

Four months of science blogging

The first posts in our science blog have given a scientist’s perspective on different areas of ECMWF’s work. Topics range from single precision computer calculations, satellite data assimilation and reanalysis to the prediction of flood and fire risk.

22 December 2017


Winter 2017/18 Newsletter published

The winter 2017/18 issue of the ECMWF Newsletter is now available. As well as news about ECMWF staff and events, it features articles about new developments and the use that can be made of ECMWF products.

19 January 2018

Ocean coupling in tropical cyclone forecasts

Tropical cyclones are one of the deadliest weather phenomena. One of the avenues being pursued at ECMWF to improve forecasts of tropical cyclones is to better take into account interactions between the ocean and the atmosphere during the forecast period.

11 January 2018

4D-Var symposium on 26 January 2018

Developing a 4D variational data assimilation system was one of ECMWF’s biggest-ever projects. It culminated in the operational implementation of 4D-Var on 25 November 1997. A symposium to mark the 20th anniversary will be held at ECMWF on 26 January and will be live-streamed.

12 January 2018

Forecast charts and data

We provide current forecasts, climate reanalyses and specific datasets. These are available via the web, point-to-point dissemination, data servers and broadcasting.

Image for Twitter windstorm David/Friederike

Plot of the week

Cyclone strike probability animation for Thursday showing successive ensemble forecasts. Includes windstorm David/Friederike that hit NW Europe - only at short leads was the track forecast correct. Predicting small, dangerous cyclones is intrinsically very challenging.



Forecasts, analyses, climate re-analyses, reforecasts and multi-model data are available from our archive (MARS) or via dedicated data servers or via point-to-point dissemination.

Accessing forecasts

Researchers, WMO members, commercial users and satellite data providers can gain access to ECMWF forecast products under one of our various license agreement types.

Advancing weather science

Education is a key element of our work at ECMWF, enabling our partners to get the most from ECMWF's services and develop an advanced understanding of forecasting.

ECMWF lecture theatre

ECMWF workshops are open to the worldwide meteorological community, though some training is restricted to member states.