Compiled by A.J. Fox

|A | B | C | D | E | F | G | H | I | J | K |
|L | M | N | O | P | R | S | T | U | V | W |

Advection - Horizontal motion, such as wind.

Air - A mix of gases that holds various amounts of particles and liquids at any given time. In our atmosphere, Nitrogen is the most abundant gas followed by Oxygen.

Air Mass - A large body of air characterized by similar physical qualities. (ie. warm air mass, cold air mass, etc.)

Air Pressure - The force exerted by a column of air above a given point.

Anemometer - an instrument used to determine wind speed.

Anticyclone - An area of high pressure.

Aphelion - The point in the orbit of a planet that is farthest from the Sun.

Atmosphere - The gaseous envelope surrounding a planet.

Aurora - A bright light display caused by solar radiation interacting with the atmosphere near the north and south poles. aurora borealis occurs in the Northern Hemisphere and aurora australis in the Southern Hemisphere.

Barometric Pressure - See Air Pressure

Bergeron Process - One process of rain formation. Supercooled water droplets connect with a particle (called freezing nuclei) to form small ice pellets. The ice pellets fall, melting on the way down, to form rain.

Biosphere - All life on planet Earth.

Blizzard - A winter storm with winds so strong, it picks up dry snow off the ground, which greatly reduces visibility.

Ceiling - The height of the lowest layer of clouds. When there are no clouds - the ceiling is said to be unlimited.

Celsius - The metric temperature scale. Water freezes at 0 degrees Celsius and boils at 100 degrees Celsius. The scale was created by Anders Celsius in 1742.

Cirrus - A type of cloud formation. These are high, thin clouds that look like wisps of cotton candy.

Climate - A description of the weather of a certain region using statistical weather data.

Cloud - A form of condensation. A concentration of water droplets or ice crystals, suspended in the atmosphere.

Cold Front - The place where an advancing cold air mass meets a warm air mass.

Collision-Coalescence Process - One process of rain formation. One small droplet collides with another, forming a larger droplet. This continues until the droplet is too heavy and falls to earth as rain.

Condensation - The change of state of a gas to a liquid.

Continental Air Mass - An air mass over land. Usually a continental air mass (indicated by the simple letter "c") is relatively dry. (also see Tropical Air Mass)

Contrail - Cloud-like stream observed behind aircraft. Caused by the addition to the atmosphere of water vapor by the engine's exhaust.

Convection - The transfer of heat by the movement of mass or substance. This only occurs in fluids. This often refers to the vertical motion of air in a thunderstorm.

Convergence - A net inflow of air. Convergence at lower levels in the atmosphere often result in cloud development and precipitation.

Coriolis Effect - Deflection of air flow in the atmosphere which is caused by the rotation of the Earth. In the northern Hemisphere, the deflection is to the right. It is to the left in the Southern Hemisphere. Named after G. G. Coriolis, a French physicist who first discussed this effect in 1844.

Cumulus - A type of cloud formation. These are billowy clouds, often described as "cottonballs".

Cyclogenesis - Term that describes the beginning or creation of a new cyclone.

Cyclone - An area of low pressure characterized by converging winds. "All storms are cyclones but not all cyclones are storms." - Liebermann.

Desert - The driest of dry climates.

Dew - A form of condensation that happens when the overnight temperatures drops to a low enough level.

Dew Point - The temperature at which dew would form.

Diurnal - Daily

Divergence - A net outflow of air from a particular area. Divergent winds at low levels are not favorable for cloud development.

Doppler Radar - A type of radar that is able to detect motion directly.

Downburst - A strong gust of wind in a downward direction. Usually associated with a thunderstorm.

Drizzle - Precipitation from stratus clouds consisting of tiny droplets.

El Nino - Periodic warming of the Eastern and Central Pacific Ocean. This can result in extreme weather events around the world.

Equinox - The point in time when the vertical rays from the Sun are striking the equator. Around March 21st, the vernal equinox occurs and the autumnal equinox happens around September 22nd.

Evaporation - A change of state from a liquid to a gas.

Eye - Referring to a hurricane, the eye is the area in the middle with light winds and fair weather.

Eye Wall - Surrounds the eye of the hurricane. This is the strongest area of the hurricane, with the most intense storm development.

Fahrenheit - A temperature scale devised by Gabriel Fahrenheit. Water freezes at 32 degrees and boils at 212 degrees Fahrenheit.

Fog - A cloud with it's base at or very near the ground.

Freeze - The change of state from a liquid to a solid.

Freezing Rain - Precipitation the starts out as rain, but when it hits the ground it instantly freezes. (see Glaze)

Front - A boundary separating air masses. One air mass is often warmer and higher in moisture content than the other.

Frontogenesis - The beginning or creation of a front.

Frost - Occurs when the temperature drops below 32 degrees Fahrenheit.

Fujita Intensity Scale - The scale of wind speed used to classify the severity a tornado. The scale was developed by Dr. T. Theodore Fujita.

FUTURECAST ®- A graphic representation of what the weather is most likely to do in the future. FUTURECAST is an exclusive feature of the KSEE 24 WEATHERLAB.

Glaze - A coating of ice that forms when supercooled rain freezes on contact. A storm that produces this is called an icing storm (also, see freezing rain).

Greenhouse Effect - Also called the atmosphere effect. Absorption of solar and terrestrial radiation by particles in the atmosphere that results in warming temperatures.

Hail - Precipitation in the form of ice pellets. Usually associated with thunderstorms.

High Cloud - a cloud that has it's base at or above 18,000 feet

Humidity - The amount of water vapor in the air. (not to be confused with Relative Humidity)

Hurricane - A tropical cyclone with minimum winds of 74 MPH(119 KPH).

Hurricane Warning - Issued when hurricane force winds are expected in a coastal area within 24 hours.

Hurricane Watch - Issued when a hurricane might strike a certain area within 36 hours.

Ice Point - The temperature when a substance changes from a liquid to a solid.

Jet Stream - Swift winds in the upper troposphere that move around in relatively narrow belts.

Kelvin - Temperature scale used primarily by scientists. The Kelvin Scale is named after the physicist who first introduced it. Also called the Absolute Scale. Zero degrees Kelvin is known as absolute zero, which is in theory, the temperature at which all molecular motion stops. To calculate Kelvins, simply add 273 to the Celsius temperature.

Lake-Effect Snow - Snow that results from a cold dry air mass moving over a relatively warm lake. The air mass acquires moisture and heat from the lake and a snow storm begins.

Land Breeze - A localized wind that blows from land to the sea. Usually occurs in the evening hours.

Lightning - A sudden flash of light generated by the flow of electrons between oppositely charged parts of a cumulonimbus cloud or between the cloud and the ground.

Low Cloud - A cloud that forms at or below 2000 meters.

Marine Climate - A climate dominated by the ocean. These areas are typically more mild.

Marine Layer - A air mass adjacent to and with temperatures similar to the ocean. The thicker the marine layer gets, the more likely it will push inland.

Marine Push - When the marine layer pushes inland. This is a major relief in the Central Valley during the summer months as cooler air comes in from the northwest.

Maritime Air Mass - An air mass that originates over the ocean. These air masses are humid.

Melting - A change of state from a solid to a liquid.

Millibar - The standard unit of pressure measurement used by the National Weather Service.

Model(s) - A series of complex physics equations, used to calculate future weather. All models start with current weather data at the time and calculate from that starting point.

Monsoon - Seasonal reversal of wind direction over large continents. This is usually associated with Asia, but the United States deals with monsoonal winds every summer.

Mountain Breeze - The nightly downslope winds encountered in mountain valleys.

Newton - Unit of force used in physics. One newton is the amount of force needed to accelerate one kilogram of something one meter per second per second.

Nor'Easter - The term used to describe a type of winter storm in the Northeastern parts of the United States. The name refers to the general direction of the wind in these types of storms - northeast.

Nowcasting - Short term forecasting techniques used to predict severe weather.

Occluded Front - A front formed when a cold front overtakes a warm front. This is usually the strongest area of a storm before it starts to fade away.

Orographic Lifting - Mountains acting as barriers to the flow of air force that air to ascend. As that air cools, clouds and precipitation may result.

Orographics - Having to do with mountains.

Ozone - An oxygen molecule. Ozone contains three Oxygen atoms.

Perihelion - The point in the orbit of a planet closest to the sun.

Persistence Forecast - Forecasting technique that says "Today's weather will be the same as yesterday's". The Central Valley sees a lot of persistence forecasts in the hot summers and foggy winters.

Polar Air Mass - A cold air mass that forms at or near the poles.

Pressure - Force. When referring to air or atmospheric pressure... it is the weight of the air above a given point.

Pressure Gradient - The change in pressure over a given distance.

Pressure Tendency - A good forecasting tool. The nature of the change in atmospheric pressure over the past several hours.

Prevailing Westerlies - The dominant west to east motion of the atmosphere that characterizes the regions on the poleward side of the subtropical highs. The Continental United States lies in this area.

Psychrometer - A device used to measure Relative Humidity and Dew Point.

Radiation Fog - Fog resulting from the nightly cooling of the ground and adjacent air. This is the main type of fog that plagues the Central Valley each year.

Rain - Precipitation in the form of water drops falling from the sky.

Rainbow - A colorful arc created by the refraction and reflection of light in drops of water.

Relative Humidity - The ratio of water vapor in the air to the air's water vapor capacity.

Revolution - The motion of one body around another. The Earth takes one year to complete one revolution around the Sun.

Ridge - An elongated region of high pressure.

Rime - Ice that forms when supercooled fog or cloud droplets come into contact with an object.

Rotation - The spinning of a body. The Earth completes one rotation every 24 hours.

Saffir-Simpson Scale - A scale used to rank hurricanes. The scale goes from 1 to 5 based upon the intensity of the winds within the hurricane.

Santa Ana Winds - Warm, dry winds that occur seasonally in the hills of Southern California. The same winds in the Rocky Mountains are called Chinooks.

Severe Thunderstorm - A thunderstorm that produces frequent lightning, damaging winds, and hail 2 centimeters or more in diameter.

Sleet - Precipitation that starts as rain and freezes or partially freezes on the way to the ground.

Smog - Air pollution. This word is a combination of "Smoke" and "Fog".

Snow - Precipitation in the form of white or clear ice crystals.

Solstice - When the vertical rays of the sun are directly over the Tropic of Cancer or the Tropic of Capricorn. These represent the days with the most and the least daylight (depending upon what hemisphere you're talking about).

Stable Air - Air that resists vertical development. Fair weather is dominant in stable air.

Stationary Front - A front which does not move.

Steam Fog - Fog that forms when cool air moves over a warm water surface.

Steam Point - The temperature when water boils.

Storm - A low pressure area that produces clouds and various forms of precipitation.

Storm Surge - The abnormal rise of the sea along a shore as a result of strong winds. Storm surge is the number one cause of property damage and death during a hurricane.

Stratosphere - The layer of the atmosphere where most of the Earth's ozone is concentrated.

Stratus - A type of cloud. Stratus clouds look like a giant grey blanket that completely covers the sky.

Sun Dogs - Two bright spots of light that sit on either side of the Sun. Sometimes called "Mock Suns".

Supercell - Name applied to a severe thunderstorm of massive size. Supercells are more persistent than a normal thunderstorm and are much more likely to produce a tornado.

Temperature - The measure of the degree of hotness of a substance

Thermal Low - An area of low pressure created by abnormal heating on the ground.

Thunder - The sound emitted by expanding gases along a lightning discharge.

Thunderstorm - A storm produced by cumulonimbus clouds that is always accompanied by lightning and thunder.

Tornado - A violent rotating column of air. Tornadoes are shaped like a funnel or tube extending from a cumulonimbus cloud.

Tornado Warning - Issued over an area when a tornado has actually been sighted or is indicated by radar.

Tornado Watch - Issued when conditions are favorable for tornado development. A tornado watch area is about 65,000 square kilometers.

Tropic of Cancer - The northern limit of the sun's vertical rays. 23 and 1/2 degrees north of the equator.

Tropic of Capricorn - The southern limit of the sun's vertical rays. 23 and 1/2 degrees south of the equator.

Tropical Air Mass - Warm to hot air mass that forms in the subtropics.

Tropical Cyclone - Also known as a tropical disturbance. A low pressure system that marks the very beginning of the life of a hurricane.

Tropical Depression - A tropical cyclone with winds less than 37 miles per hour(61 KPH).

Tropical Storm - A tropical cyclone with winds ranging from 37 to 74 miles per hour(61 to 199 KPH).

Troposphere - The lowest part of the atmosphere. The area where all weather occurs.

Trough - An elongated region of low pressure.

Unstable Air - Air that does not resist vertical displacement. Thunderstorms are easily created in an unstable atmosphere.

Upslope Fog - Fog that is created when air moves up a mountain slope.

Valley Breeze - Daily upslope winds usually encountered in a mountain valley.

Virga - Technically, a form of precipitation. Water that falls from a cloud, but evaporates before it hits the ground.

Visibility - The greatest distance that objects can be seen with the naked eye.

Warm Front - The place where an advancing warm air mass meets a cold air mass.

Weather - The state of the atmosphere at any given time.

Weather Analysis - Collecting and compiling current weather data. A necessary step in weather forecasting.

Weather Forecasting - Predicting the future state of the atmosphere.

WEATHERLAB - The place from which all weather forecasts and graphics are created for use on KSEE 24 NEWS. The meteorologists on staff use the four sophisticated computers in the WEATHERLAB to accomplish this task on a daily basis.

Wind - Air flowing horizontally (with respect to the Earth's surface.)

Windchill - A measure of apparent temperature using the effect of wind and temperature on the cooling rate of the body.

Wind Vane - An instrument used to determine wind direction.