More open water on rivers and lakes that add to the near-ground moisture.
Alberta Walker writes:
We have been having fog here all week no planes here since Sunday
There has been persistent, foggy conditions in some parts of the state in late October and early November. We have shared this observation with the National Weather Service (NWS NOAA).
National Weather Service Consult from Rick Thoman:
Strong high pressure over Alaska has trapped moisture near the ground over large parts of the state. The unusually mild October has contributed to a slower than average freeze-up, so there is more open water on rivers and lakes that add to the near-ground moisture. Thoman R. Climate Science and Services Manager, NWS NOAA.
Fog is often described as a stratus cloud resting near the ground. Fog forms when the temperature and dew point of the air approach the same value (i.e., dew-point spread is less than 5°F) either through cooling of the air (producing advection, radiation, or upslope fog) or by adding enough moisture to raise the dew point (producing steam or frontal fog). When composed of ice crystals, it is called ice fog. (NOAA)
There are several types of fog: Radiation fog forms when all solar energy exits the earth and allows the temperature to meet up with the dew point. Precipitation Fog forms when rain is falling through cold air. Advection Fog forms from surface contact with horizontal winds. Steam Fog is commonly seen in the Great Lakes but can be seen on any lake. Upslope Fog forms adiabatically. Adiabatically is the process that causes sinking air to warm and rising air to cool. Valley Fog forms in the valley when the soil is moist from previous rainfall. Freezing Fog occurs when the temperature falls at 32°F (0°C) or below. Ice Fog is only seen in the polar and arctic regions. (NOAA)