Which situation is most likely to produce clear skies and dry conditions?

The situation most likely to produce clear skies and dry conditions is strong isobar divergence. Strong isobar divergence typically occurs when air is spreading out in the upper atmosphere, leading to a reduction in surface pressure. This often results in the air being drawn upwards, cooling and allowing moisture to condense, but as this happens, the air can become sufficiently dry. The upward movement of air associated with strong divergence can lead to the dissipation of clouds and precipitation, thereby creating clear skies.

In contrast, other options like strong isobar convergence generally lead to rising air, which can result in cloud formation and precipitation. Weak isobar divergence suggests a more stable atmosphere that does not encourage significant lifting or vertical movement, while close isobar spacing indicates strong pressure gradients, often associated with stormy or unstable weather conditions. Therefore, the characteristics of strong isobar divergence align with the formation of clear and dry weather, making this the most fitting choice.