Complex sentence: However, neither of the official Regional Specialized Meteorological Centers for the eastern north Pacific, the National Hurricane Center and the Central Pacific Hurricane Center, include this system in their annual archives, nor is it included in the official "best track" file.
Split into simpler sentences: However, neither of the official Regional Specialized Meteorological Centers for the eastern north Pacific, the National Hurricane Center and the Central Pacific Hurricane Center, include this system in their annual archives. Nor is it included in the official "best track" file.