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Air Masses. Air Mass. An air mass is a body of air that is characterized by similar temperatures and amounts of moisture at any given altitude. can be 1600 km and several km thick take several days to move Source region- Characteristics that air takes on from it’s place of origin.
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Air Mass An air mass is a body of air that is characterized by similar temperatures and amounts of moisture at any given altitude. can be 1600 km and several km thick take several days to move Source region- Characteristics that air takes on from it’s place of origin
Movement of air masses As it moves the characteristics of an air mass change = weather change in the area where to air mass moves
Classifying air masses • Temperature • Surface of which they form Continental air masses – form over land= dry Maritime- form over water = humid
4 basic air masses • Continental polar(cP)- dry and cool • Continental tropical (cT)- dry and warm or hot • Maritime polar (mP)- cold and humid • Maritime tropical (mT)- warm and humid
Weather in North America Influenced by cP and mT air masses cP- cause large amount of snow over the Great Lakes (lake effect snows) mT- cause high temperatures and oppressive humidity in eastern US
Air mass tracks or paths: • If moving from the south, they move east and north. • From the north they move east and south. • For the most part they move from the west to east.
FRONTS Boundary that separates 2 air masses -created when two air masses meet
Types of Fronts 1. Cold Fronts 2. Warm Fronts 3. Stationary Fronts 4. Occluded Fronts
WARM FRONTS • Forms when warm air moves into an area formerly covered by cooler air • Gradual slope • Slow movement • Produces rain or snow
Cold Fronts • Forms when cold, dense air move into a region occupied by warmer air • Steep slope • Move quickly • Violent weather (heavy downpours and gusty winds) • cold weather • after the front • passes
Stationary and Occluded Fronts Stationary: Forms when movement is almost parallel to line of front so front does not move Occluded: forms when an active cold front overtakes a warm front = some precipitation