Phys Geo... Chapter 7

• - extensive body of air that has relatively uniform properties in the horizontal dimension and moves as an entity.
• - large, uniform entity

Formed by remaining over a uniform land or water which will allow it to develop uniform temperature and humidity.

• - central/northern Canada
• - very cold, very dry, very stable
• - winer

• - central/ northern canada
• - cold, dry, very stable air mass
• - winter

- as cold an dry as continental polar

principal source of moisture

summer air mass, hot, dry, unstable

• - zone of discontinuity between unlike air masses
• - Warm front brings warm air masses and a cold front brings cold air masses

• - large migratory low pressure system that occurs within mid lats, moves with westerlies, involving interaction of warm and cold air masses along defined fronts.
• - life cycle could be from a few hours to a few weeks

• - originate from rosspy waves
• - follow flow of polar front jet streams

- when cold front overtakes the warm front

• - a large migratory high-pressure cell of the middle latitudes that moves with westerlies.
• - clockwise air circulation and usually no rain
• - air flows down unlike regular cyclone therefore no rain, also no frotns
• - larger than MLC

• - both are migratory systems within westerlies.
• - usually form together
• - but can occur independently
• - dominantly in winter and follow polar front jet streams.

• - intense, revolving, rain-drenched, migratory and destructive cyclone in tropics and subtropic latitudes, containing very high wind.
• - North and Central America - Hurricane
• - Western North Pacific- Typhoon
• - Philippines- Baguious
• - Indian ocean and Australia- Cyclone

• - low pressure systems, circular shape
• - winds must exceed 74 mph