There's an odd greenish haze in the sky that I've never seen a camera properly capture and you don't just hear the sound of the tornado with your ears, you can feel it in your bones first. All of those tiny hairs all across your body, it's almost like they have an electric charge. When it gets close, the air gets odd and it starts to feel like there's suddenly not enough of it.
Rationally, it's a lot of contributing factors getting amped up by the biggest adrenaline rush you've ever had. It was my first season after moving a bit farther west than I'd ever been and I felt like I opened the front door to find myself within 100 feet of the thing, but it is hard to trust yourself to look back on something like that with a scientific mind. The feeling I got didn't even feel like fear, it was just a feeling of 'have to go' and I've never felt it again. For the actual situation, everything my body was telling me was worthless and nothing I could have done would have done any good if my luck had failed me, but the Tornado was just passing by on it's way to somewhere else.
Mine was a bit farther back... would be measured in decades ago, I may turn to dust shortly, but maybe same area. It's crazy how much the strength of tornadoes ramps up on the western half of the state.