Marinetime tropical air mass (mT)

-develop over the subtropical oceans and transport heat and moisture northward into the U.S

-The northward movement of tropical air masses transports warm moist air into the United States, increasing the potential for precipitation.

Continental Polar Air Mass (cP)

-originate over the northern plains of Canada, transport colder and drier air southward.

-Arctic air masses move about as a shallow area of high pressure(A high pressure center is where the pressure has been measured to be the highest relative to its surroundings), commonly known as an "Arctic High". This type of air mass generally brings in colder weather and not much precipitation.