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Storm Tracker Documents: Forecast Errors

The track forecast error bounds shown on the TSR Storm Tracker represent the mean distance between forecast and actual tropical cyclone positions at all lead times over a number of previous years. These errors are calculated by each tropical cyclone forecasting centre (see the Data document for more about these centres) 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 previous 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) used by the TSR Storm Tracker.

RegionMean Position Error for each Forecast Lead Time (nm)Data Period
0 h 12 hrs 24 hrs 36 hrs 48 hrs 72 hrs 96 hrs 120 hrs
North Atlantic 7.7 24.1 36.9 49.6 65.1 96.3 133.2 171.6 2015-2019
North East Pacific 8 21.8 34 44.9 55.3 77.1 99.1 123.2 2015-2019
North West Pacific 24 34 46 61 78 117 165 223 2014-2018
North Indian 35 39 43 52 65 88 120 167 2014-2018
Southern Hemisphere 31 40 50 65 83 119 162 223 2014-2018



Researched and Developed by Mark Saunders and Frank Roberts
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