Which factor does not indicate potential cloud formation with fronts?

D is the correct choice because ground visibility conditions do not directly influence the formation of clouds associated with weather fronts. Instead, factors such as dew point level, pressure changes, and temperature gradients are critical in cloud formation.

The dew point level indicates the amount of moisture in the air; when the air temperature cools to the dew point, condensation occurs, leading to cloud formation. Pressure changes often accompany fronts as they create lifting mechanisms that allow air to rise and cool, further promoting cloud growth. A temperature gradient between two air masses can also contribute to instability in the atmosphere, which is essential for clouds to develop when the warmer, more buoyant air rises over the colder, denser air associated with a front.

In contrast, ground visibility conditions primarily reflect the overall weather situation and do not inherently denote cloud formation processes, as they can remain clear or low regardless of the presence of clouds above. Thus, while ground visibility might be influenced by the weather conditions, it does not serve as a predictive factor for the actual cloud development that occurs with weather fronts.