Weather and Climate

cold front

A front where cold air moves in under a warm air mass.

Low pressure

A mass of rising warm air air that usually bring stormy weather.

High pressure

A mass of sinking cool air that usually bring fair weather.

High to Low pressure

How winds move related to pressure

Westerlies

The dominant winds that move across the USA

drought

a long period of unusually dry weather

humidity

amount of moisture in the air

climate

long-term average of weather in an area

Pressure

the amount of force pushing on an area

warm front

Forms when warm air slides up and over a cold air mass; it brings gentle rain or light snow followed by warmer weather.

Land breeze

Movement of air from land to sea at night, created when cooler, denser air from the land forces up warmer air over the sea

precipitation

any form of water that falls from clouds and reaches Earth's surface

weather

day-to-day changes in atmospheric conditions, including temperature, air pressure, humidity, wind, cloud coverage, or precipitation

Layers of the atmoshere

earth's surface troposphere;stratoshere;mesoshere;thermosphere

altitude

elevation above sea level

jet stream

fast moving stream of wind where cold, polar air meets warm air from the equator

air mass

large body of air with the same temperature and humidity

Sea Breeze

movement of air from sea to land during the day when cooler air from above the water moves over the land, forcing the heated, less dense air above the land to rise

Coriolis effect

the change that Earth's rotation causes in the motion of objects and that explains how winds curve

water cycle

the continual movement of water among Earth's atmosphere, oceans, and land surface through evaporation, condensation, and precipitation

atmosphere

the layer of gases that surrounds Earth

air pressure

the pressure caused by the weight of a column of air pushing down on an area

condensation

the process by which molecules of water vapor in the air become liquid water

evaporation

the process by which water molecules in liquid water escape into the air as water vapor

dew point

the temperature at which the water vapor in the air becomes saturated and condensation begins

barometer

tool that measures air pressure

wind vane

tool that measures wind direction

anemometer

tool that measures wind speed

front

where two different air masses meet normally causing precipitation