NCEP currently runs storm tracker over model forecast grid data from NWP centers around the world to track storms in both tropical and extratropical regions. Real time forecast storm tracks are then plotted and imported to this page for monitoring. It contains track plots from various models, including the NCEP GFS, NCEP NAM, NCEP global ensemble, NCEP short range ensemble (SREF), as well as UKMET and NOGAPS models, Canadian high resolution model and ensemble, and ECMWF model and ensemble. Most recent 45 day's tracks can be displayed.
For forecast tracks:
In order to measure the accuracy of the model forecast tracks, a "truth" has to be established for verification. In the tropical storm cases, Hurricane Prediction Center issues "observed" tracks as the "truth". But no such luxuries are available for extratropical storms. The next best thing would be analysis cyclone tracks that are embedded in the forecast track files. By linking these analysis storm centers sequentially, storm tracks are identified.
For analysis tracks:
Extratropical cyclone forecast verification
Now there are model forecast cyclone tracks and analysis tracks available. Absent of real track observations similar to hurricane tracks, the analysis tracks can be used as the truth for the forecast tracks verification. More detailed description about the verification processes can be found at "NCEP Operational Global Cyclone Tracking and Verification System.""Operational Extra-Tropical Cyclone Tracks Verification System."
Operational cyclone track errors
Following table provides model forecast cyclone track errors in unit of KM from NCEP operational models and from other centers. Each plot displays past 10 days verification against analysis tracks.For forecast track errors: