Meterology

Atmosphere

The layer of gases surrounding Earth, held by gravity. The atmosphere is composed mainly of nitrogen and oxygen and plays a crucial role in weather and climate by containing air, moisture, and heat.

Barometer

An instrument used to measure atmospheric pressure. Barometers help meteorologists predict weather changes by tracking pressure fluctuations.

Cumulus

A type of cloud characterized by fluffy, white, cotton-like appearance. These clouds usually indicate fair weather but can grow into larger storm clouds under the right conditions.

Dew Point

The temperature at which air becomes saturated with moisture and dew forms. It is an important measure of atmospheric moisture and comfort level.

El Niño

A periodic warming of the central and eastern Pacific Ocean that affects global weather patterns. This phenomenon can lead to changes such as increased rainfall or drought in different parts of the world.

Front

A boundary separating two air masses with different temperatures and humidity. Fronts often bring changes in weather, such as precipitation or shifts in wind direction.

Gale

A very strong wind, typically between 34 and 40 knots (39–46 mph). Gales can cause hazardous conditions, especially at sea.

Humidity

The amount of water vapor present in the air. High humidity can make temperatures feel warmer and affect weather patterns.

Inversion

A reversal of the normal decrease of air temperature with altitude, trapping pollutants near the ground. Temperature inversions can lead to smog and poor air quality.

Jet Stream

A narrow band of strong wind in the upper atmosphere that influences weather systems. These winds can steer storms and affect temperature patterns.

Köppen Climate Classification

A widely used system for classifying the world’s climates based on temperature and precipitation. It helps scientists compare and study different climate zones globally.

Lapse Rate

The rate at which air temperature decreases with increasing altitude. Understanding lapse rates is important for weather prediction and aviation.

Meteorology

The scientific study of the atmosphere and weather processes. Meteorologists analyze data to forecast weather and understand climate behavior.

Nimbus

A type of cloud that produces precipitation, such as rain or snow. Nimbus clouds are dense and dark, often signaling storms.

Orographic Lift

The process of air rising over mountains, cooling, and causing precipitation. This phenomenon explains why mountainous areas often receive more rainfall.

Pressure Gradient

The rate of atmospheric pressure change over a certain distance, influencing wind speed and direction. A steep pressure gradient results in stronger winds.

Radar

A system using radio waves to detect precipitation and storm movement. Radar data helps track storms and forecast their paths.

Saturation

The point at which air contains the maximum amount of water vapor it can hold at a given temperature. Beyond this point, excess moisture condenses into clouds or dew.

Thunderstorm

A storm characterized by thunder, lightning, heavy rain, and sometimes hail. Thunderstorms form from rapidly rising warm air and moisture.

Ultraviolet Radiation

High-energy electromagnetic radiation from the sun affecting weather and climate. UV radiation influences temperature and can cause sunburn.

Vortex

A rotating column of air, such as a tornado or cyclone. Vortices can vary greatly in size and intensity.

Warm Front

The leading edge of a warmer air mass moving into a cooler area. Warm fronts often bring gradual temperature increases and precipitation.

Weather Balloon

A balloon carrying instruments that measure atmospheric conditions at various altitudes. Data from weather balloons is critical for understanding upper-air weather patterns.

Xerophyte

A plant adapted to survive in environments with little water. In meteorology, xerophytes indicate arid or dry climate conditions.

Yardstick (Weather)

Informal term sometimes used for measuring or estimating precipitation or snow depth. Though not an official instrument, it refers to simple measurement tools.

Zephyr

A gentle, mild breeze typically from the west. The term is often used poetically to describe soft winds.

Advection

The horizontal transport of heat, moisture, or other atmospheric properties by the wind. This process redistributes energy and moisture across different regions.

Blizzard

A severe snowstorm with strong sustained winds and reduced visibility. Blizzards can create dangerous travel conditions and cause power outages.

Cloud Seeding

A technique to stimulate precipitation by dispersing substances like silver iodide into the air. It aims to encourage cloud droplets to form raindrops.

Doppler Radar

Radar technology that measures the velocity of precipitation particles to detect storm movement and intensity. It helps meteorologists identify severe weather such as tornadoes.

Evaporation

The process where liquid water changes into water vapor and enters the atmosphere. Evaporation is a key part of the water cycle influencing humidity and precipitation.

Fog

A thick cloud of tiny water droplets suspended near the Earth’s surface reducing visibility. Fog often forms when air cools to its dew point.

Greenhouse Effect

The warming of Earth’s surface caused by trapped heat from greenhouse gases like carbon dioxide. It is essential for life but can be intensified by human activities.

Heat Index

A measure that combines air temperature and humidity to estimate how hot it feels. High heat index values indicate dangerous heat stress for humans.

Isobar

A line on a weather map connecting points of equal atmospheric pressure. Isobars help visualize pressure systems and predict wind flow.

Jet Stream

A fast-flowing air current in the upper atmosphere that influences weather patterns. The position and strength of jet streams affect storm tracks and temperature distribution.

Katabatic Wind

A cold, dense wind that flows downhill under the force of gravity. These winds can cause rapid temperature drops and are common in polar and mountainous regions.

Lightning

A sudden electrostatic discharge during a thunderstorm. Lightning produces heat, light, and thunder, and can be dangerous to life and property.

Microburst

A small but intense downdraft of wind that causes localized damage. Microbursts can be hazardous to aircraft and cause severe wind damage near the ground.

NOAA

National Oceanic and Atmospheric Administration, a U.S. agency focusing on weather, ocean, and atmospheric research. NOAA provides vital weather forecasts and climate data.

Occluded Front

A weather front formed when a cold front overtakes a warm front, often bringing complex weather. Occluded fronts usually result in precipitation and temperature changes.

Precipitation

Any form of water—rain, snow, sleet, or hail—that falls from clouds to Earth. Precipitation is a critical component of the water cycle.

Quasi-Biennial Oscillation (QBO)

A regular variation in the winds in the tropical stratosphere occurring about every 28 months. The QBO influences weather and climate patterns worldwide.

Relative Humidity

The percentage of moisture in the air relative to the maximum it can hold at that temperature. It affects comfort, evaporation, and cloud formation.

Storm Surge

An abnormal rise of seawater during a storm, caused by strong winds pushing water toward the shore. Storm surges can cause flooding and coastal damage.

Tornado

A violently rotating column of air extending from a thunderstorm to the ground. Tornadoes can cause extreme destruction over localized areas.

Updraft

An upward air current that can lead to cloud formation and storms. Strong updrafts are essential for the development of severe thunderstorms.

Vapor Pressure

The pressure exerted by water vapor in the air. Vapor pressure is important in understanding humidity and condensation.

Waterspout

A tornado occurring over a body of water. Waterspouts can be less intense than land tornadoes but still dangerous.

X-band Radar

A radar operating in the X frequency band, useful for detecting small precipitation particles. It is often used in weather research and localized forecasts.

Yield (in precipitation)

The total amount of precipitation collected over a period. Yield measurements help assess rainfall and snow accumulation.

Zonal Flow

Atmospheric flow pattern that moves west to east along latitude lines. Zonal flow often brings stable weather conditions.

Albedo

The measure of reflectivity of a surface, expressed as a percentage. Surfaces with high albedo, like snow and ice, reflect most sunlight, affecting Earth’s energy balance and climate.

Anemometer

An instrument used to measure wind speed. It is commonly used in weather stations to monitor and forecast weather conditions.

Atmospheric Pressure

The force exerted by the weight of air in the atmosphere. It influences weather patterns and is measured in units like millibars or inches of mercury.

Backdoor Cold Front

A cold front that moves in from the northeast or east, opposite the usual west or northwest direction. It often brings sudden temperature drops in spring and fall.

Cap (Capping Inversion)

A layer of warm air aloft that suppresses convection and prevents thunderstorms from forming. Breaking the cap can lead to severe storms.

Chinook Wind

A warm, dry wind that descends the leeward side of mountains, causing rapid temperature increases. It’s common in the Rocky Mountains region.

Convection

The vertical movement of air caused by heating near the Earth’s surface. Convection is responsible for cloud formation and thunderstorms.

Dendritic Growth Zone

The temperature range in clouds favorable for the formation of snowflakes with complex, branched shapes.

Downburst

A strong downward rush of air from a thunderstorm that can cause damaging winds on or near the ground.

Equinox

The two times each year when day and night are approximately equal in length worldwide, marking the start of spring and autumn.

Foehn Wind

A warm, dry wind on the leeward side of mountains, similar to Chinook winds, known in Europe and other regions.

Gust Front

The leading edge of cooler air rushing out from a thunderstorm, often causing sudden wind shifts and temperature drops.

Hurricane

A tropical cyclone with sustained winds exceeding 74 mph, characterized by a low-pressure center and intense rainfall.

Index of Refraction

A measure of how much light bends when it passes through different atmospheric layers. This affects phenomena like mirages.

Lenticular Cloud

Lens-shaped clouds formed over mountain peaks due to orographic lift and wave patterns in the atmosphere.

Madden-Julian Oscillation (MJO)

An eastward-moving disturbance of clouds, rainfall, and winds near the equator with a cycle of 30-60 days influencing tropical weather.

Nimbostratus

Thick, dark clouds that produce continuous precipitation, usually rain or snow, often covering the sky.

Occlusion

The process by which a cold front overtakes a warm front, creating complex weather conditions typical in mature cyclones.

Polar Vortex

A large area of low pressure and cold air surrounding the Earth’s poles, which can expand and cause cold outbreaks at lower latitudes.

Rain Shadow

A dry area on the leeward side of a mountain range caused by precipitation being blocked by the mountains.

Snow Squall

A sudden, intense snowfall event accompanied by strong winds, leading to rapidly reduced visibility and hazardous driving.

Trade Winds

Persistent easterly winds found in the tropics, important for global circulation and weather patterns.

Unstable Air

Air that tends to rise because it is warmer and less dense than surrounding air, often leading to cloud formation and storms.

Vorticity

The measure of rotation in the atmosphere, important for understanding cyclones and storm development.

Wind Shear

A change in wind speed or direction over a short distance. Wind shear can influence storm intensity and aviation safety.

Zonda Wind

A hot, dry wind descending the eastern slopes of the Andes in Argentina, similar to a Foehn wind.

Air Mass

A large body of air with relatively uniform temperature and humidity characteristics. Air masses influence the weather of the regions they move into.

Baroclinic Zone

A region in the atmosphere where temperature gradients exist, often associated with fronts and storm development.

Chinook Arch

A distinctive, arch-shaped cloud formation often seen on the windward side of mountain ranges during Chinook winds.

Cloud Condensation Nuclei (CCN)

Tiny particles like dust or salt that water vapor condenses onto to form cloud droplets.

Dry Line

A boundary that separates moist air from dry air, commonly found in the central U.S., often triggering severe thunderstorms.

Enhanced Fujita Scale (EF Scale)

A scale used to rate the intensity of tornadoes based on damage caused, ranging from EF0 to EF5.

Freezing Rain

Rain that falls as liquid but freezes upon contact with cold surfaces, causing ice accumulation.

Gravity Wave

Oscillations in the atmosphere caused when air is displaced vertically and gravity tries to restore equilibrium, often creating wave-like cloud patterns.

Hail

Precipitation in the form of balls or lumps of ice, formed in strong thunderstorms with intense updrafts.

Ice Fog

A type of fog consisting of tiny ice crystals, typically occurring in very cold environments.

Jet Streak

A localized region of stronger winds within a jet stream, which can influence weather systems and storm development.

Kelvin Wave

A type of atmospheric or oceanic wave important in tropical weather phenomena such as El Niño.

Lake-Effect Snow

Heavy snow caused when cold air moves over warmer lake waters, picking up moisture and depositing it downwind as snow.

Meso-scale Convective System (MCS)

A complex of thunderstorms that organizes on a scale larger than individual storms but smaller than large-scale weather systems.

NOCTILUCENT Clouds

Rare, high-altitude clouds visible at twilight, made of ice crystals in the mesosphere.

Orographic Cloud

Clouds formed as moist air is forced to rise over a mountain range.

Potential Temperature

The temperature air would have if compressed or expanded adiabatically to a standard pressure level, used to assess atmospheric stability.

Rain Gauge

An instrument used to measure the amount of precipitation over a specific period.

Sea Breeze

A local wind blowing from the sea toward the land, caused by temperature differences between the two.

Thermocline

A layer in a body of water where temperature changes rapidly with depth, influencing weather and climate near coasts.

Upwelling

The rising of cold, nutrient-rich water from deep ocean layers to the surface, affecting coastal climate and ecosystems.

Virga

Precipitation that evaporates before reaching the ground, often seen as streaks beneath clouds.