Label the air near each high as cold or warm. Air masses are named according to their moisture and temperature characteristics. On weather maps, the abbreviations cP, cT, mP, mT are used. The first letter of each abbreviation is not capitalized to avoid confusion with other abbreviations. Label the map with the air mass abbreviations.
Fronts are the boundaries between air masses, marking the edges of individual air masses.
Draw solid lines where the air from different air masses meet. Prevailing winds cause air masses and the fronts that form between them to move. If warm air replaces cold air, it is called a warm front. If cold air replaces warm air, it is called a cold front. Refer to the Windy Noteguide for prevailing wind information.