Typhoon Muifa (Unding) caused considerable damage when it crossed the northern Bicol provinces and Southern Mindoro during the two-day period: November 19-20, 2004. The typhoon was remarkable because its movement was erratic, being characterized by a looping trajectory and other deviations from a smooth track. These characteristics may be seen in Fig. 1.
The typhoon began as a weak disturbance east of Northern Mindanao and developed into a tropical depression on November 14. The disturbance continued to intensify as it moved approximately along a northwestward path toward Luzon. On November 17, the disturbance began an anticyclonic looping movement near the eastern coast of Luzon while it intensified into a typhoon. The looping ended during the latter part of November 19 when it turned abruptly and accelerated toward the southwest.
The present study attempts to explain the erratic movement of the typhoon. More specifically, we will test the hypothesis that the erratic movement of Typhoon Muifa is due to changes in the steering flow or the large scale environmental flow in which the typhoon is embedded.
[Presented at the Okinawa Typhoon Center Forum, 1 October 2005, Okinawa, Japan.]