Here are some of the reasons why an air mass that forms over Alaska is likely to be cold and dry:
* Alaska's location: Alaska is located at a high latitude, which means that it receives less sunlight than areas closer to the equator. This makes Alaska colder than other parts of the United States.
* The Arctic Ocean and the Pacific Ocean: The Arctic Ocean and the Pacific Ocean surround Alaska and have a significant influence on the climate of the state. These bodies of water are cold and can cause the air to become cold and dry.
* The prevailing winds: The prevailing winds in Alaska come from the north and the east. These winds bring cold air from the Arctic Ocean and the Pacific Ocean into Alaska.
As a result of these factors, an air mass that forms over Alaska is likely to be cold and dry.