★★ Biting cold, and a sky slightly lighter than medium gray. The gray of a sparsely populated subway platform when every train but the C has already just been through. But a D train came after all, before too long, and the sun began to shine through. Then the sun vanished again and a few snowflakes came twisting down. Half the sky had gone bluer and half darker. Actual brightness came for a while and then faded. People were keeping their hoods up inside the subway station. At Columbus Circle, a wash of even colder air trickled along the 1 platform. At Lincoln Center, snow came blowing down the exit steps, a squall heavy enough for streaks of snow to blow along the surface of Broadway in the headlights.