Could someone please explain this, someone who knows a good amount of meteorology. Now, we just had pretty decent thunderstorm, not much thunder or lightning, it was mostly a heavy rain shower; it turned it a to be beautiful when it became a sun shower with double rainbows. Anyway, could someone tell me why did the barometric pressure increase during the shower, and then decreased after it ended. Normally, I would think it should decrease because of an updraft. Could a downdraft cause this? Here's the data from the shower: