METEOROLOGY

Comprehensive vocabulary flashcards covering key meteorology concepts, atmospheric layers, weather phenomena, hazards, and aviation weather products.

Atmosphere

The life-giving mixture of gases surrounding Earth.

Nitrogen

Gas composing about 78% of Earth’s atmosphere.

Oxygen (atmospheric)

Gas composing about 21% of Earth’s atmosphere.

Troposphere

Lowest atmospheric layer, extends roughly 6–7 miles and features decreasing temperature with altitude.

Tropopause

Thin boundary above the troposphere that traps most water vapor and weather.

Stratosphere

Layer 7–22 miles high where some clouds and severe thunderstorms can reach.

Mesosphere

Atmospheric layer roughly 45–51 miles above Earth.

Thermosphere

Outermost atmospheric layer.

International Standard Atmosphere (ISA)

Reference atmosphere with sea level pressure 29.92 in.Hg (1013.2 hPa) and temperature 15 °C.

Standard lapse rate

Decrease of 2 °C (3.5 °F) and 1 in.Hg per 1,000 ft altitude gain.

QNH

Altimeter setting for sea-level pressure.

QNE

Altimeter setting for pressure altitude.

QFE

Altimeter setting giving height above the field elevation.

Convection

Circulating motion where warm air rises and is replaced by cooler air.

Coriolis Force

Deflection caused by Earth’s rotation, varying between equator and poles.

Meteorology

Science dealing with physical properties of the atmosphere and weather processes.

Air mass

Large body of air with fairly uniform temperature and moisture.

Source region

Area where an air mass acquires its temperature and moisture characteristics.

Continental Polar (cP)

Cold, dry, stable air mass originating over polar land.

Maritime Tropical (mT)

Warm, moist, unstable air mass originating over warm water.

Cloud

Visible mass of tiny water droplets or ice crystals condensed onto nuclei.

Stratus

Low, layered cloud forming in stable air near the surface.

Stratocumulus

Low, white puffy cloud layer.

Nimbostratus

Thick, dark low cloud containing large amounts of moisture and precipitation.

Altostratus

Middle-level flat, dense gray or white cloud covering a wide area.

Altocumulus

Middle-level patchy gray-white clouds producing light turbulence and icing.

Cirrus

High, thin wispy cloud.

Cirrostratus

High, thin white sheet-like cloud often causing halos.

Cirrocumulus

High, white patchy clouds resembling cotton.

Towering Cumulus

Large vertically expanding cumulus with cauliflower tops signaling instability.

Cumulonimbus

Thunderstorm cloud; large, vertically developed with heavy moisture.

Cumulus

Cloud with flat base and dome-shaped top; indicates turbulence, little icing.

Precipitation

Any form of water particles falling from atmosphere to surface (rain, snow, hail, etc.).

Evaporation

Change of liquid water into invisible water vapor.

Condensation

Change of water vapor into liquid.

Sublimation

Direct change of ice to water vapor.

Deposition

Change of water vapor directly to ice.

Relative Humidity

Ratio of actual moisture to maximum possible at a given temperature.

Dewpoint

Temperature at which air becomes saturated with water vapor.

Stable air

Cool, dry air resisting vertical motion, typical of polar regions.

Unstable air

Warm, moist air favoring vertical motion and thunderstorms.

Isobar

Line connecting points of equal barometric pressure on a map.

Pressure gradient

Rate of pressure change over a given distance.

High-pressure system

Anticyclone; air flows clockwise in Northern Hemisphere.

Low-pressure system

Cyclone; air flows counter-clockwise in Northern Hemisphere.

Ridge

Elongated area of high pressure.

Trough

Elongated area of low pressure.

Col

Neutral region between two highs or two lows or ridge–trough intersection.

Wind

Movement of air relative to Earth’s surface.

Anemometer

Instrument measuring wind speed and direction.

Sea breeze

Daytime wind blowing from cool water toward warmer land.

Land breeze

Nighttime wind blowing from cooler land toward warmer water.

Valley wind

Daytime upslope flow as warmer mountain air rises and valley air moves upward.

Mountain wind

Nighttime downslope flow of cooler air into valley.

Katabatic wind

Any wind flowing downhill due to gravity.

Foehn wind

Warm, dry, descending wind on leeward side of mountains.

Radiation fog

Ground fog forming on clear, calm, moist nights by surface cooling.

Advection fog

Fog formed when warm moist air moves over a cooler surface.

Upslope fog

Fog produced as moist stable air is forced up rising terrain.

Precipitation-induced fog

Fog created when warm rain evaporates into cooler near-surface air.

Steam fog

Sea smoke; forms when cold dry air moves over warmer water.

Haze

Visibility reduction by fine salt or dust particles suspended in air.

Smog

Mixture of smoke and fog causing very poor visibility.

Mist

Suspension of tiny water droplets formed when warm moist air is rapidly cooled.

Ice accretion

Gradual build-up of ice on aircraft surfaces under icing conditions.

Airframe icing

Ice formation on external aircraft surfaces.

Engine icing

Ice formation affecting engine inlets or carburetor.

Turbulence

Rapid, irregular air motion causing abrupt changes in velocity.

Wake turbulence

Wingtip vortices created whenever an aircraft produces lift.

Jet blast

Hazardous high-velocity exhaust stream from jet engines.

Cold front

Boundary where advancing cold air displaces warmer air.

Warm front

Boundary where advancing warm air overrides colder air.

Stationary front

Front that shows little or no movement.

Occluded front

Front formed when a cold front overtakes a warm front.

Thunderstorm

Storm produced by cumulonimbus clouds with lightning and thunder.

Cumulus stage

First thunderstorm stage with continuous updrafts.

Mature stage

Stage when precipitation begins and downdrafts develop.

Dissipating stage

Final thunderstorm stage dominated by downdrafts.

Mountain wave

Oscillating airflow on leeward side of mountains causing turbulence.

ATIS

Automatic Terminal Information Service; continuous broadcast of airport information.

METAR

Hourly aviation routine weather observation report.

SPECI

Special unscheduled METAR issued for significant changes.

TAF

Terminal Aerodrome Forecast describing expected conditions for 24 h.

PIREP

Pilot weather report of in-flight conditions.

AIRMET

Advisory of potentially hazardous weather (Sierra, Tango, Zulu).

SIGMET

Advisory of severe weather posing serious threats to all aircraft.

Surface Analysis Chart

Chart showing current surface pressure systems, fronts, and weather every 3 h.

Weather Depiction Chart

3-hourly chart summarizing surface conditions from METARs.

World Meteorological Organization (WMO)

UN agency coordinating international meteorological cooperation.

Climatology

Scientific study of climate patterns and variations.