| A | B |
|---|
| thermometer | a tool used to measure air temperature. |
| barometer | an instrument used to measure air pressure. |
| windsock | a cone-shaped cloth bag open at both ends used to measure wind direction. the wide end points into the wind. |
| anemometer | an instrument used to measure wind speed. |
| radar | it is used to find the location, movement, and amount of precipitation. it can also detect what form of precipitation a weather system carries. |
| windsock | an instrument that measures wind direction |
| H | high pressure |
| L | low pressure |
| cT | continental tropical; warm and dry; forms over land |
| cP | continental polar; cold and dry; forms over land |
| mT | maritime tropical; warm and wet, moist; forms over water |
| mP | maritime polar; cold and wet, moist; forms over water |
| weather | the short-term state of the atmosphere, including temperature, humidity, precipitation, wind, and visibility |
| humidity | the amount of water vapor in the air |
| condensation | occurs when water vapor cools and changes from a gas to a liquid |
| cloud | a collection of small water droplets or ice crystals suspended in the air, which forms when the air is cooled and condensation occurs |
| cumulus clouds | puffy, white clouds that tend to have flat bottoms; form when warm air rises; they usually indicate fair weather, but if they get larger, they can produce thunderstorms |
| -nimbus or -nimbo | clouds that include this in their name are likely to produce precipitation |
| stratus clouds | clouds that form in layers; often block out the sun |
| nimbostratus clouds | dark stratus clouds that produce light to heavy, continuous rain |
| cirrus clouds | thin, feathery, white clouds found at high altitudes; form when the wind is strong; indicate that a change in weather is coming |
| precipitation | any form of water that falls to the Earth's surface from the clouds |
| cold front | froms when cold air moves under warm air, which is less dense, and pushes the warm air up; brings thunderstorms, heavy rain, or snow; cooler weather |
| warm front | froms where warm air moves over cold, denser air; warm air gradually replaces cold air; bring drizzly rain and followed by clear warm weather |
| stationary front | forms when a cold air mass meets a warm air mass and both air masses do not have enough force to lift the warm air mass over the cold air mass; brings many days of cloudy, wet weather |
| occluded front | form when a warm air mass is caught between two colder air masses; the coldest air mass moves under and pushes up the warm air mass; brings cool temperatures and large amounts of rain and snow |
| cumulonimbus clouds | produce thunderstorms |
| dew point | the temperature at which a gas condenses into a liquid |
| front | the boundary between air masses of different densities and usually different temperatures |
| air mass | a large body of air where temperature and moisture content are constant throughout |
| cyclone | an area in the atmosphere that has lower pressure than the surrounding areas and has winds that spiral toward the center |
| anticyclone | the rotation of air around a high-pressure center in direction opposite to Earth's rotation |
| cold front | (blue used for symbol) A cold air mass moves under a warm, less dense air mass |
| warm front | (red used for symbol) A warm air mass moves over a cold, denser air mass |
| occluded front | (purple used for symbol) A warm air mass is caught between two colder air masses |
| stationary front | (red and blue used for symbol) A cold air mass meets a warm air mass and the two air masses remain separated |
