It was quite the foggy start to Monday in western Massachusetts.
We had quite a lot of fog here in western Massachusetts Monday morning.
This type of fog is known as advection fog as it’s all about the movement of air masses. We had cold air at the ground and warmer moist air arriving.
Problem is that warmer, moist air was being cooled by the colder air it was replacing and it got cooled down to the dew point.
When the temperature and the dew point are the same you get fog developing, and we certainly had it very dense in spots.