As the cyclone passed Motion_directional over increasingly cool sea surface temperatures and became Becoming intertwined in a baroclinic zone , it began Process_start to undergo an extratropical transition .

The system subsequently started Process_start to move Motion towards the southeast during December 29 , in response Response to a strengthening Cause_change_of_strength steering flow , provided Supply by an upper level trough of low pressure and a baroclinic system near New Caledonia .