Complex sentence: During that day Sina's eye became very distinct on satellite imagery, as it intensified and the upper level steering flow which resulted in Sina moving erratically towards the southeast and Fiji.
Split into simpler sentences: During that day, Sina's eye became very distinct on satellite imagery. As the system intensified and came under the influence of a changeable upper level steering flow which resulted in Sina moving erratically towards the southeast and Fiji.