Tropical Cyclone Diagrams - TCs

In operational environments, when output from several NWP models or ensembles are available, forecaster analysis of tropical cyclone forecasts is viable only when the information on position and intensity of tropical cyclones is displayed in a compact and easy-to-understand format.  The ECMWF tropical cyclone forecast products are designed to clearly provide both deterministic and probabilistic information on the movement and intensity of individual tropical cyclones after post-processing of IFS forecast data at 6 hour intervals.  This also helps with the objective verification of tropical cyclone forecasts, and can also help with highlighting unreliable aspects. IFS model analyses of tropical cyclones rely on observed data alone - there is no artificial scheme, such as vortex bogussing, for arbitrarily defining the structure of the modelled tropical cyclone.

The output charts show the evolution of the position and intensity of tropical cyclones in the ENS and HRES forecasts and provide an objective measure of the uncertainty in the current forecast.

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)