Saw very bright, large-ish dot that collapsed to smaller dot and disappeared

I was on my back porch after having added a potato skin to my compost tumbler. I noted the odd weather, which has been threatening storms all day, but it has not actually rained yet. It is eerily dark outside and feels oppressive, probably from the high pressure system moving in. I walked back up on my porch and turned around to look back out over the yard and I saw a bright light, a warmish shade of bright bright white, brighter than anything else in the sky or around me. It was not terribly far or high, and looked like it might be over the river or just past it, and not even as high as the hill behind it. (Crane Hill, Unadilla). It was, from my perspective a bit smaller than the moon would look. It held for just a moment and then shrank down into a smaller dot, perhaps half its original size with no change in brightness or color. Then it simply vanished.