The track forecast error bounds shown on the TSR Storm Rainfall pages represent the mean distance between the Met Office model forecast and actual tropical cyclone positions at all lead times over a number of recent years. These errors are calculated by the Met Office during the post tropical cyclone season assessment of their forecast performance. The errors represent the average performance of tropical cyclone track forecasts at given lead times in a particular region during recent years. As such they do not indicate a definitive bound on the actual future cyclone position and serve as an indication only.
The table below shows the error values (in nautical miles) from the Met Office model.
| Region | Mean Position Error for each Forecast Lead Time (nm) | Data Period | 24 hrs | 48 hrs | 72 hrs | 96 hrs | 120 hrs |
|---|---|---|---|---|---|---|
| North Atlantic | 68.9 | 119.4 | 169.7 | 223.4 | 300.4 | 2001-2005 |
| North East Pacific | 67.3 | 113.8 | 163.7 | 226.3 | 309.8 | 2001-2005 |
| North West Pacific | 72.7 | 127.0 | 190.0 | 256.5 | 335.7 | 2001-2005 |
| North Indian | 101.6 | 157.6 | 221.8 | 233.7 | 218.0 | 2001-2005 |
| Southern Hemisphere | 89.6 | 138.9 | 191.7 | 268.1 | 352.1 | 2001-2005 |
