Download Student Lecture Notes CH 20

Lecture Notes: CH 20 Weather
20.1 Air Masses
• immense body of air with ________________________ and amounts of moisture
Classifying Air Masses
 air masses are also classified according to the _______________ which they form.
Weather in ___________________________
 is influenced by continental Polar (____) and maritime Tropical (____) air masses.
 California: maritime Polar (_______) and maritime Tropical (mT) air masses
Continental Polar Air Masses _________________ in winter and cool and dry in summer.
Maritime Tropical Air Masses ________, loaded with moisture, and usually _________.
Maritime Polar Air Masses ______________________ air masses in Siberia.
Continental _______________ Air Masses in the ________________, it can cause
extremely ________________-like conditions in the Great Plains.
What kind of weather could be expected In southern Canada if a mT air mass
was to invade the region in mid July? ___________________________________
20.2 Fronts
- Formation of Fronts
 When two air _________________________, they form a front, (which is a ________
that separates two air masses).
Types of Fronts
_______________ • forms when warm air moves into an area of cooler air.
Draw 
________________forms when cold, dense ________________ a region of warmer air.
Draw 
__________________ when the ____________________ position of the front
________________ move, and a stationary front forms.
Draw 
When an active ______________________________ front, an occluded front forms.
Draw 
Middle-latitude cyclones are large ____________________________ that generally
travel from ______________________ and cause ______________ weather.
More often than not, air ____ up in the atmosphere __________ a middle-latitude cyclone.
What happens when two air masses meet? _____________________________
20.3 Severe Storms
Occurrence of Thunderstorms
• there are an estimated __________ thunderstorms in progress on Earth
Thunderstorms form when _______________________ in an _________ environment.
 Tornadoes the _________ extends downward from a _________________ cloud.
Occurrence and Development of Tornadoes - form in association with severe thunderstorms
A _________ is a vertical cylinder of rotating air that develops in the updraft of a ______
Where is Tornado Alley (area of country, a few states) ____________________
How are tornadoes measured? What scale? _______________________
Whirling _______________ that produce __________ of at least 119 kilometers per hour
(_______mph) are known in the United States as hurricanes
Most hurricanes form _______________________ degrees north and south ________.
Hurricanes develop most often in the _____________ when water temperatures are ____
A _____________ is the abnormal rise of the sea along a shore as a result of strong winds.
How are hurricanes measured? What scale? _______________________
Explain why a hurricane quickly loses Strength as the storm moves onto land.