Complex sentence: The wave was moving towards the west at the rate of 23 mph (37 km/h), due to an area of high pressure located over the north-central Atlantic Ocean leading to a prevailing easterly flow.
Split into simpler sentences: The wave was moving towards the west at the rate of 23 mph (37 km/h). This was due to an area of high pressure located over the north-central Atlantic Ocean leading to a prevailing easterly flow.