You are approaching an airport to land in 20 minutes. The weather report indicates temperature and dew point are both 10 degrees C. What do you expect?

When both the temperature and dew point are the same, it indicates that the air is fully saturated with moisture, reaching 100% relative humidity. In these conditions, condensation occurs, leading to the formation of fog, particularly radiation fog.

Radiation fog traditionally forms overnight when the ground loses heat through radiation, cooling the air near the surface to the dew point, or it can develop in stable air conditions during the day if the atmospheric temperatures drop. In this scenario, with a temperature and dew point at 10 degrees Celsius, it is reasonable to expect that radiation fog would form, especially if the cooling conditions are suitable.

The other scenarios reviewed would not typically manifest under these atmospheric conditions. For example, deepening fog generally implies expansion or thickening of an existing fog layer, which may not be applicable if one is simply encountering saturated air conditions. Clearing conditions would not logically follow from saturated air, as those imply reduced humidity and evaporation, leading to dry air. High winds with scattered clouds would indicate instability and dry conditions rather than the saturation indicated by equal temperature and dew point readings.

Thus, the presence of identical temperature and dew point strongly supports the likelihood of radiation fog forming as you approach the airport.