5 air masses that affect the united states are continental polar(cP), continental arctic(cA), continental tropical(cT),maritime polar(mP) and maritime tropical(mT).
The source of origin of cP is the snowy regions of Canada and Alaska ,of cA is the Arctic basin, of cT is Mexico and south west US, of mP is the Northern Pacific Ocean and mT is the Gulf of Mexico,the Carribean sea,western Atlantic and subtropical Pacific.
<u>Explanation:</u>
Air masses are volumes of air that has uniform characteristics. Air masses are divided into two based on its moisture content. They are continental air mass and maritime air mass which are dry and moist respectively.
The first letter in the abbreviation of an air mass denoted whether the air mass is continental or maritime. The letter c represents continental air mass and letter m represents maritime air mass. The source of origin of the air mass is represented by the second letter in the abbreviation of the air mass.
Air mass with tropics as the source of origin is represented by the letter T, air mass with equator as the source is represented by letter E, air mass with pole as the source is represented by the letter P and air mass with the Arctic or Antarctic as the source is represented by the letter A.
