Which of the following describes a Continental Arctic (cA) airmass?

A Continental Arctic (cA) airmass is characterized as generally very dry, very cold, and stable. This type of airmass originates over landmasses located in polar regions, such as the Arctic. Because it forms over land and in such cold conditions, the cA airmass has minimal moisture content, making it quite dry. Additionally, the extremely low temperatures associated with this airmass mean that it is stable, contributing to clear skies and typically calm weather patterns.

Unlike the other choices, which describe conditions associated with different types of airmasses, the Continental Arctic airmass’s dry and stable nature is critical for understanding its impact on weather. For instance, a moist and hot airmass would lead to thunderstorms and instability, while descriptions of moist and cold with low instability or warm and unstable at high altitudes refer to airmasses that exhibit different characteristics and behaviors influenced by moisture and temperature variations.