Late summer Passumpsic fog

Late August is a time of thick nightime fog in the Passumpsic valley. Traces of temperature and dewpoint at the LSC weather station show how this fog evolves overnight. The fog is present when temperature is equal to the dewpoint between midnight and about 9 AM. At that point the sun begins rapidly warming the surface of the earth and the fog quickly evaporates. This can be confirmed in the time lapse video of the LSC baseball field below.

It looks like the fog will not set in as rapidly in the evening and start sometime around 1 AM the following night.

Figure 1: Top frame shows evolution of temperature, dewpoint and relative humidity starting at 00:00 and ending 23:55 for Tuesday, 26 August 2014.