Summary

  • ECMWF has made a subset of its highest-resolution IFS forecast data free and open. The new 0.1° feed arrives about two hours after the existing 0.25° feed.
  • Both grids come from the same underlying forecast. Users who need the fine grid immediately can still obtain it through a service agreement.

A valley can disappear inside a broad forecast cell. ECMWF's 20 October release gives flood and health-risk model builders a finer public view of terrain and temperature. The catch is on the clock: the free fine-grid data are published about two hours after the coarser open feed. The full-resolution stream remains available in real time under a service agreement. For an agency deciding when to run its next model, spatial detail and delivery time now sit on different sides of the purchase order.

The open-data catalogue says what was released. From 20 October, IFS outputs are distributed at 0.1° as well as the existing 0.25°. Both are interpolated from the same high-resolution forecast of roughly 9 km; 0.1° is the delivery grid, not a new independent model. The finer stream carries a subset of ECMWF's full real-time catalogue and includes extra fields for local model initialisation. ECMWF's earlier free feed remains available at the end of its normal real-time dissemination schedule. Its new fine-grid files follow roughly two hours later, with separate WIS2 notices.

That interval buys time for the provider's network and protects commitments to member and cooperating states. It also changes a downstream operation. A hydrological model can use the finer fields to separate a steep catchment from its neighbours, while an urgent response may need to start with the earlier 0.25° product. ECMWF says a paid service agreement remains the route to real-time high-resolution delivery. The agency that uses these forecasts has to set the decision deadline itself; a sharper map arriving after that deadline cannot move it backwards.

The technical release note puts numbers on the file choice. The 0.1° grid has 2.5 times finer horizontal spacing and 6.25 times as many grid points over the same area. ECMWF splits its surface and pressure-level files, letting a low-bandwidth user fetch only one set. Its public portal keeps the latest 12 forecast runs, roughly two to three days, and varies simultaneous connection capacity between 500 and 2,000; cloud mirrors provide another route. Public data may be reused commercially with attribution.

The release opens a useful product, not every ECMWF parameter. The public records provide no measured improvement for a particular town's warning from this distribution change; a before-and-after verification of that town's downstream model would settle the practical gain. The open door matters because more teams can test the fine grid. The two-hour gap matters because the team that needs both speed and detail still has to pay or redesign its timing.