Most deserts are a result of the rainshadow effect, cold currents, the subtropical ridges, or a combination of those. Knowing this, how is the Somali desert caused?
It is notable since it has a desert climate close to the equator, which is known for being wet. Furthermore, it is on the East Coast of Africa, and Eastern Coasts within 0 to 45 degrees latitude are almost always wet.
I've searched and read about the rainshadow effect of the Ethiopian highlands causing the rainshadow effect. However, the trade winds go towards the East, which should make Somalia even wetter. I've read about the monsoon effect, which would explain the rainshadow effect... for the summer. In the winter, however, the wind should bring moist air back to Somalia. So if anything, Somalia should be a tropical Mediterranean climate. Reports say that entire years can go by without rain though.
In summary, my question asks for the cause(s) of the Somali desert being so dry and why it isn't a Mediterranean climate.