Here are a couple more early cover designs (again done by the talented J. Kent Holloway).
African Firestorm started off as one story, but changed as I write the outline and when I actually started writing. Rick Chesler supplied the basic idea, that of Somali pirates. But as I researched, I saw that for the most part, Somali pirates problem was over. I like the idea of using piracy in that part of the world, so I used it as a base of the story.
For the rest, I looked at what was going on in the world. The Iran nuclear situation, ISIS, and North Korea became pieces of the puzzle from the start, but as I wrote it, the original back half of the book wasn't working. I sat back, talked to Rick and we rethought the back half of the book. The original climax was a raid on a ship, followed by a second raid on a second ship. While it looked great in the outline, when it came to write it, it didn't jell. So, one ship boarding done away with. Then the original terrorist target also stopped working, so that was tossed and a new target found, one that made more sense and added a level of tension that wasn't there before.
Then it was figuring out what was the missiles range was, and how close the bad guys had to be to fire it. The range of F-18s as well as their speed at different altitudes. There was a neat scene about a pair of F-18s shattering a ship's windows with a point-blank sonic boom, only to find the Mythbusters beat me to it (and busted it), as well as realizing that such a stunt was stupid on a ship with AA missiles onboard. So, their role changed. I made sure the F-18 squadron was a real one based on a real aircraft carrier. I used Wikipedia extensively on a number of novel-related subjects.
I tried to make it realistic as I could, which is why I worried about missile ranges, F-18 capabilities, what ships were where, real locations for scenes, and the weapons the characters used. I watched videos on container ships, trying to get a look and feel what it would be like for the action on-board ship. Somali culture became part of the story, the use of Khat and the plight of the Somali people. Where I couldn't get a clear answer, I made one up. Where I won't say, but I hope it doesn't distract from your enjoyment of the novel. I know I have been rather vague, but I don't want to spoil the surprise!
The next Outcast Ops novel I'm working on, Red Ice, has the first thirty chapters outlined. A different style of story, it still have plenty of action. Hopefully, it will be out in the summer.