Arab maybe introducing play finally enters a turbulent area (5,9)

I haven't cracked this one yet — but the brilliant team at Times for the Times have:

Wiki unhelpfully but probably accurately says “these are are the latitudes about 30 degrees north and south of the Equator. They are characterized by sunny skies, calm winds, and very little precipitation. They are also known as subtropical ridges or highs. It is a high-pressure area at the divergence of trade winds and the westerlies.” Perhaps more knowledgeable geographers than I can justify the “turbulent” tag. Anyway the Arab is an example of a HORSE, play is LATITUDE, and add the S from the end of (finally) enterS