Air Masses and Fronts An air mass is

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. m. T

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

• 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