Note: HRES and Ensemble Control Forecast (ex-HRES) are scientifically, structurally and computationally identical.  With effect from Cy49r1, Ensemble Control Forecast (ex-HRES) output is equivalent to HRES output shown in the diagrams.   At the time of the diagrams, HRES had resolution of 9km and ensemble members had a resolution of 18km.

Tropical Cyclone Diagrams - TCs

The various positions and intensities forecast by an ensemble need to be displayed in a compact and easy-to-understand format.   Tropical cyclone products are produced at 6hr intervals after post-processing of IFS forecast data.  For the current forecast they provide for each individual tropical cyclone: 

  • deterministic and probabilistic information on the movement and intensity.
  • an objective measure of the uncertainty in the current forecast.

This helps with the objective verification of tropical cyclone forecasts, and can also help with highlighting unreliable aspects.

Evaluation of tropical cyclone tracks for the sub-seasonal range ensemble is computed at 6hr intervals in the same way as medium range ensemble and the outputs are consistent.

IFS model analyses of tropical cyclones rely on observed data alone.  There is no artificial scheme, such as vortex bogusing, to arbitrarily define the structure of the modelled tropical cyclone.

RSMC official forecasts of tropical cyclones take precedence

Note: IFS products on these pages regarding tropical cyclones are generated automatically without any editing by forecast experts.   RSMCs (Regional Specialized Meteorological Centres) have ultimate responsibility for official forecasts of tropical cyclones within their respective regions (ECMWF is one of a number of centres that provide data to them).  Up-to-date information is available by direct access to official RSMC forecasts through the WMO Severe Weather Information Centre.  For up-to-date forecast information for their own local area users should refer to forecasts from their own National Meteorological Service.

Additional Sources of Information

(Note: In older material there may be references to issues that have subsequently been addressed)



(FUG Associated with Cy49r1)