What does "regression" refer to in weather phenomena?

The term "regression" in weather phenomena relates specifically to the concept of returning to a previous state, particularly when discussing the transition of severe weather conditions. It implies that after experiencing a phase of severe weather, the system can revert back to an earlier state of weather that was less severe or different in nature. For example, after a severe storm, conditions may improve and revert to what they were prior to the storm, thus representing a regression in the weather pattern back to a calmer state. This understanding is crucial for meteorologists when predicting weather changes and understanding the cycles of weather systems.

Other choices, while relevant to weather discussions, do not capture the specific idea of regression. Developing new weather systems and unexpected weather patterns represent different phenomena that do not imply a return to a prior state. The transition from fog to clear skies is more about clearing conditions rather than a regression to previous weather.