The weather today was wonderful. Warm air, cold snow, and a deep, clear blue sky.
Something about the temperature and visibility made it an excellent day for watching contrails. Two stuck out over the course of the day, both probably departures from Logan airport. One was so crisp that all four engines left distinct contrails behind the plane. The two inner trails seemed to point toward each other, while the outer pair spread further out.
The other one, perhaps left by a plane in a holding pattern, was a perfect S curve. It reminded me of a skier’s parallel tracks in the snow.