WEATHER. rain. thunder. The explosive sound of air as it is heated by lightning.

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1 WEATHER rain thunder The explosive sound of air as it is heated by lightning.

2 rainbow lightning hurricane They are intense storms with swirling winds up to 150 miles per hour. tornado

3 cold front warm front A boundary between two air masses, one cold and the other warm, moving so that the colder air replaces the warmer air The boundary between two air masses, one cool and the other warm, moving so that the warmer air replaces the cooler air. radar An electronic instrument, which determines the direction and distance of objects that, reflect radio energy back to the radar site. This is what meteorologists use to see rain or snow. meteorologist A scientist who studies and predicts the weather. Meteorologists use sophisticated equipment, like Doppler radar and supercomputers, but they also rely on oldfashioned sky watching.

4 weather vane thermometer barometer An instrument that measures air pressure. Almanac A calendar that uses astronomical information and weather data. Almanacs list tide data, give the positions of the stars and forecast weather each day.

5 anemometer A weather instrument that measures the wind speed. Arctic Air An air mass that originates over Canada and brings us cold temperatures. blizzard breeze

6 climate It describes the average weather conditions in a certain place or during a certain season. clouds cirrus clouds Thin, wispy clouds that form high in the atmosphere as their water vapor freezes into ice crystals. Cirrus clouds are a principle cloud type. cumulus clouds Fluffy, mid-level clouds that develop in towering shapes and signal fair weather. Cumulus clouds are a principle cloud type.

7 stratus clouds Low-lying, gray and sheet like clouds that often produce drizzle. Stratus clouds are a principle cloud type. cumulonimbus clouds A dense and vertically developed cloud that produces thunderstorms. The cloud can bring heavy showers, hail, lightning, high winds and sometimes tornadoes. nimbus The Latin word for "rain" used to describe a cloud or group of clouds from which rain is falling. flood It results from days of heavy rain and/or melting snows, when rivers rise and go over their banks.

8 precipitation General name for water in any form falling from clouds. This includes rain, drizzle, hail, snow and sleet. Although, dew, frost and fog are not considered to be precipitation. condensation The change of water vapor to liquid water, as when fog or dew forms. evaporation The process of changing a liquid (like water) to a vapor. It s the opposite of condensation. cyclone A low pressure system. It is a term variously applied to tornadoes, waterspouts, dust storms, hurricanes and even to any strong wind.

9 fog A cloud on the ground that reduces visibility. drought A period when a region has a lack of rainfall. dew Water that forms on objects close to the ground when its temperature falls below the dew point of the surface air. earthquake The shaking or movement of a portion of the Earth's surface.

10 hail A mixture of liquid and frozen precipitation. snow global warming The theory that increased concentrations of greenhouse gases are causing the Earth s surface temperature to warm. greenhouse effect The heating effect of the Earth's atmosphere.

11 heat accumulation lightning tornado warning It s issued to warn the public, emergency management, and other cooperating agencies when a tornado is forecast to occur or is occurring. tornado watch It s issued when conditions are favorable for the development of tornadoes.

12 earth latitude The position of the Earth s surface north or south of the equator. equator The imaginary great circle of 0 degrees latitude on the Earth's surface, separating the Northern Hemisphere from the Southern Hemisphere. longitude The position of the Earth s surface east or west of the Greenwich meridian.

13 overcast When a widespread layer of clouds covers all of the sky. There may be thin or bright spots in the cloud layer, but no openings. ozone A form of oxygen that has a weak chlorine odor. Ozone heats the upper atmosphere by absorbing ultraviolet from sunlight. seasons flurries Summer Spring Fall Winter

14 Fahrenheit Celsius tsunami A Japanese term for an unusually large ocean wave caused by undersea earthquake, landslide, or volcanic eruption.