Satellites: NOAA-15 and NOAA-17, part of NOAA's 850km-high (530 mile-high) Polar Orbiting satellites

Anatomy of a snowstorm
This image shows the class scenario of warm, wet air being brought up from the Gulf of Mexico and meeting cold air from the north.
The cold air of the jet stream can be seen dipping down from Canada through the northeastern US states, sitting ready to condense any moisture that hits it.
The twisting path of the jet stream takes it just below Hudson Bay, and then detours down across Pennsylvania, New York, etc.
Click on the image below for a higher-resolution (>100k) version.