Operational forecasting process of Extratropical Transition of Tropical Cyclone

When typhoons are decaying stage, they interact with synoptic scale in the midlatitudes, so called, extratropical transition (ET). The extratropically transitioning cyclones have been shown to have a large effect on weather system in the midlatitues and cause sometimes the severe weather phenomena. However, both operational forecasting and research aspect of ET remain a significant challenge. Because it is difficult to distinguish ET stage due to obscure configuration of the cyclone itself. Furthermore, any definition of ET should not only be precise enough to satisfy the needs of the operational and research communities and should be accessible to the general public as well. Therefore, the “operational manual for ET” was proposed and has been used to diagnose both structure and subsequent process of ET since August 2007. In this manual, it has been examined the maximum wind and SST in the 1st step, satellite image in the 2nd step, sounding in the 3rd step, surface weather chart analysis in the final step (Fig. 1). This operational manual has allowed better monitoring and understanding of the changes in the structure as ET occurs.

Acknowledgment

This research was carried out as a part of “Valuation on Precision Improvement of Surge Prediction System” supported by METRI.