Dawn, January 1, 2018
[Photo: KPA]
A frozen Lake Ontario is in the horizon
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Lake Effect Clouds:
What happens is that the cold dry air is coming in from the west and picks up moisture, as I described above. The air over the warmer lakes is rising, though. The cold air is blowing above it, acting like a lid to the rising warm, moist air. The rising air is stopped, and flows around to either side (imagine a plume of, say, cigarette smoke hitting the ceiling; at the top it splits and flows away from the plume with circular vortices). It cools and sinks, forming two circular patterns that rotate horizontally in opposite directions. The wind stretches them out, blowing them downwind, forming long streamers. This happens all up and down the coast, so you get a big series of cylindrical clouds, each one rotating in the opposite sense of the one next to it.