1.] The boundary between two air masses of different density. When it does not move, it's called "stationary"; "warm" when warmer air replaces cooler air; "cold" when cooler air replaces warmer air. Front: The transition zone between two air masses of... Cold front: The boundary between two air masses.
2. Continental polar (cP) or continental arctic (cA) air masses are cold, dry, and stable. ... Maritime tropical (mT) air masses are warm, moist, and usually unstable. Some maritime tropical air masses originate in the subtropical Pacific Ocean, where it is warm and air must travel a long distance over water.
3.] When a weather front passes over an area, it is marked by changes in temperature, wind speed and direction, atmospheric pressure, and often a change in the precipitation pattern...