There comes a time during the process of writing a novel where separate threads begin to come together. Themes start to connect to themes and one incident influences another. This miracle will often happen on its own, which is why you always hear writers giving such advice about not forcing things. The human mind is wired to look for connections and set structure to the world. This same principle also holds true for the fictional worlds one creates.
I'm about halfway through the manuscript I'm working on and over the past few days, those connections have started revealing themselves to me. The funny thing about it is that I was just prepared to do an outline because I wasn't seeing them. Sometimes thinking it out on paper will reveal what the actual manuscript isn't showing...but alas, they came anyway. For the sake of swiftness, I've decided to go ahead with outlining the rest of the story, but an outline is far more effective when one knows how the pieces all fit together.