Air Masses and Fronts An air mass is a large body of air that has the same temperature, and humidity throughout (moisture) A source region is where the air mass forms, and takes on those characteristics Ex. Forms over water – high moisture Forms over land – low moisture Forms over low latitudes – high temp. Forms over high latitudes – low temp.

Air mass that form over land are called continental = (c) Air masses that form over water are called maritime = (m)

Air masses that form at high latitudes (cold) are called – polar (P) Air masses that form at low latitudes (warm) are called – tropical (T) Air masses are identified by two letters, first describes the moisture, the second describes the temperature. Ex. mT

Fronts A front is a boundary where two air masses meet A cold front forms when cold air moves into an area occupied by a warmer air mass

Characteristics of a cold front: Moves rapidly Stays close to the ground – more dense Associated with dark clouds Precipitation is brief, but heavy Associated with severe weather, thunderstorms, hail, and tornadoes

Characteristics of a warm front are: A warm front forms when warm air moves into an area occupied by a colder air mass Characteristics of a warm front are: Slow moving high thin cirrus clouds form in front of the warm front Precipitation is long, but light Less dense air moves up and over cold more dense air mass

Stationary fronts form where cold and warm air masses meet, and both air masses have equal force, Cold front has same strength as warm front Many days of precipitation

Occluded fronts form where a warm air mass is caught between two cooler air masses. Two cooler air masses move the warm air mass up, cooling of the air mass occurs and cloud formation with precipitation will happen