|From 1 June 2004, JMA narrowed probability circles* for the tropical cyclone
(TC) track forecast. This improvement is based on the verification results
of the recent TC track forecasts.
The verification of our forecasts from 2001 to 2003 indicated the feasibility of reduction in the radii of the probability circles by about 10% on an average compared to the previous ones, in particular 25% for TCs with the movement speed of more than 15kt (Fig.).
The narrowed provabiliy circle is expected to allow disaster prevention activities to be more effectively coordinated.
1 June 2004
|Fig.: Example of the improvement of the TC track forecast
This shows a comparison of the new probability circle with the old one in the case of a track forecast of TY ETAU (0310) issued at 12UTC 6 August 2003. The red solid circles indicate new probability circles, and the blue dashed ones describe old probability circles.