Precipitation Mechanisms, Air Masses, Fronts, and Storm Systems

Vocabulary flashcards covering the four precipitation mechanisms, classifications of air masses and fronts, types of precipitation, and storm systems.

Orographic Precipitation

Precipitation produced when moist air rises over mountains, cools, and condenses.

Windward Side

The side of a mountain facing incoming moist air, typically receiving more precipitation.

Leeward Side

The side of a mountain where air descends, warms, and becomes drier.

Rain Shadow

A dry region on the leeward side of a mountain caused by moisture loss on the windward side.

Chinook Winds

Warm, dry winds descending the leeward slopes of mountains.

Frontal Precipitation

Precipitation formed when warmer air rises along the boundary between different air masses.

Convective Precipitation

Precipitation where surface heating causes warm air to rise, cool, and condense, sometimes forming thunderstorms.

Convergent Precipitation

Precipitation produced when air flows together toward a low-pressure area and is forced upward, forming clouds and precipitation.

Air Mass

A large body of air with relatively uniform temperature and humidity.

Continental (c)

An air mass originating over land; generally dry.

Maritime (m)

An air mass originating over oceans; generally moist.

Tropical (T)

A warm air mass.

Polar (P)

A cold air mass.

Arctic (A)

A very cold air mass.

Cold Front

A boundary where advancing cold air pushes warm air upward rapidly, often producing intense showers or thunderstorms.

Warm Front

A boundary where advancing warm air rises over retreating cold air, often producing widespread, steady precipitation.

Rain

Liquid water droplets falling to Earth's surface.

Snow

Ice crystals that form and combine into snowflakes.

Freezing Rain

Liquid precipitation that freezes when it contacts a surface below $0^\circ\text{C}$.

Sleet (Ice Pellets)

Precipitation that melts in a warm air layer and refreezes before reaching the ground.

Graupel

Soft snow pellets formed when supercooled droplets freeze onto snowflakes.

Hail

Balls of ice formed within thunderstorms by strong updrafts.

Temperature Inversion

An atmospheric condition where temperature increases with altitude, important in freezing rain and sleet formation.

Extratropical Cyclone

A midlatitude low-pressure storm associated with strong temperature differences and often weather fronts; can produce blizzards, heavy rain, and strong winds.

Tropical Cyclone (Hurricane)

A powerful low-pressure storm developing over warm ocean waters, fueled by moisture and latent heat release, without fronts.

Eyewall

A ring of intense winds and heavy precipitation surrounding the eye of a hurricane.

Mesoscale Convective System

An organized group of thunderstorms formed by rapidly rising moist, unstable air.

Thunderstorm

A storm involving strong upward air movement, condensation, and latent heat release.

Microburst

A powerful localized downdraft from a thunderstorm.

Tornado

A rapidly rotating column of air extending from a thunderstorm toward the ground.

Pressure Gradient Force

A force created by air pressure differences that initiates wind.