ECMWF AIFS Ensemble Release

Greetings! We are pleased to announce the availability of the ECMWF AIFS Ensemble v1 at WeatherBELL. This major addition to the global suite of numerical weather prediction modeling provides an innovative approach to ensemble construction and demonstrates significant improvement in skill and spread for most parameters and lead times.

WeatherBELL has made available its full suite of ensemble products for this dataset.

The ECMWF notes the following:

On Tuesday 1 July 2025, a first version of the probabilistic model of the Artificial Intelligence Forecasting System (AIFS) will be released and supported operationally. The model version is AIFS ENS v1, which will replace the current experimental model AIFS ENS DIFF.

AIFS ENS data has undergone internal analysis, demonstrating significant skill and highlighting its transformative impact. We encourage users to read this webpage, which outlines outstanding known issues, before considering using the data for operational use/integration in applications. We would welcome any feedback.

The source data are currently in a release candidate phase, with full implementation expected with the 06 UTC 1 July 2025 run. The data are produced 4 times per day, with a forecast duration of 15 days, and 0.25 degree spatial resolution for all fields.

• Maps
• Meteograms
• Hovmoller Diagrams
• Teleconnections

WeatherBELL products for the ECMWF AIFS ENS v1 will be available on the following schedule:

There are some known issues with the ECMWF AIFS ENS v1. Please see Known AIFS ENS Forecasting Issues - Forecast User - ECMWF Confluence Wiki for further information.

About the AIFS Ensemble
Please see Implementation of AIFS ENS v1 - Forecast User - ECMWF Confluence Wiki for further details regarding the ECMWF AIFS Ensemble v1.

Other Additions

Relative humidity RTMA plots

RDPS on the 0.09º rotated lat/lon grid

Expanded coverage over the northern Atlantic Ocean, Mexico and Central America, Caribbean Sea, North Pacific Ocean, and even parts of northern Europe.

UV index RDPS meteograms

UKMET Open Data schedule

Now scheduled to begin updating at 0:545 UTC and 17:45 UTC, for the 00z and 12z runs respectively.