1. Convection Currents Air in our atmosphere is constantly moving.
Land gets warm more quickly in daylight than water. At night, land cools faster than water. This causes the air above land and water to have different temperatures. The different temperatures will result in winds, storms and cause convection currents to form.
Convection Currents gases or liquids will rise and sink in a circular path.
Cool Air= gas particles are closer together than in warm air.
When cool and warm air are next to each other, cool air will sink and warm air will rise.
Convection Currents will flow in the opposite direction at night versus during the day.
6 convection currents form in the air above Earth. Tropical Regions get warmer than other parts of the Earth.
The combination of the 6 convection currents and the spinning of the Earth causes wind patterns.
Winds blow from west to east.
Jet Stream is a band of very fast wind formed by the different temperatures between convection currents.

4. Air Masses
Air Masses are large bodies of air that move across land, bringing in weather. The type of weather depends on where the air mass developed. The most important properties are temperature and water vapor.
4 kinds of air masses:
1) Continental Polar Air: land near the poles is not very moist, air mass is cold and dry.
2) Continental Tropical Air: large hot desert cause air to be warm and dry
3) Maritime Tropical Air: Air is humid, air mass is warm and humid, water can easily evaporate.
4) Maritime Polar Air: air mass is cold and moist
Weather will stay the same until a new air mass comes in. Air masses move due to wind.

7. A front is a boundary between two air masses and move west to east.
Weather Fronts
A front is a boundary between two air masses and move west to east.
A front gets its name from the kind of air that moves into the area. Cold front brings cold air mass to replace the warm air mass.
Warm front brings warm air, often producing rain.
A stationary front cold and warm air meet and stay put.
Occluded Front a cold and warm front both move in, but the cold air front moves in faster, pushing the warm air front up, often producing rain.

10. Pressure Systems
High pressure system - means good weather, cool and dry air. On a weather map a high pressure system is shown by a blue H.
Low pressure system- means rainy or cloudy weather, have warm and moist air. On a weather map a low pressure system is shown by a red L.