ATMO 201 Exam 3 Vocabulary Flashcards

This set of vocabulary flashcards covers key concepts from ATMO 201 Exam 3, including air masses, frontal systems, cyclogenesis, and severe weather phenomena such as thunderstorms and tornadoes.

mT Air Mass

Maritime Tropical air mass that forms over the waters of the Gulf of Mexico, bringing hot and highly humid air to Southeast Texas during the summer.

cA Air Mass

Continental Arctic air mass which originates over polar regions, making it the coldest and driest air mass on Earth.

cT Air Mass

Continental Tropical air mass that forms over subtropical hot land areas and results in hot and dry weather.

mP Air Mass

Maritime Polar air mass that forms over oceans and adds moisture to the atmosphere.

Air Mass Source Region

Generally flat areas of uniform composition with light surface winds that allow air to remain still and absorb temperature and moisture.

Stationary Front

A front where the weather remains the same for days without significant change.

Cold Front

A boundary where warm air is lifted ahead of cold, polar air, often creating showers followed by a temperature drop and shifting winds from southwesterly to northwesterly.

Warm Front

A boundary depicted by red semicircles pointing toward colder air, where warm air overrides cold surface air, often creating a sequence of snow, sleet, freezing rain, and rain.

Occluded Front

A weather boundary formed when a fast-moving cold front overtakes a slow-moving warm front, lifting the warm air mass off the ground.

Cyclogenesis

The official term for the development or strengthening of a middle latitude storm system.

Warm Sector

A wedge of warm, humid air trapped in the southern portion of a cyclone, located behind a warm front but ahead of an advancing cold front.

Nor'easters

Midlatitude storms found along the Atlantic coast of North America formed by the collision of cold land air and warm Gulf Stream ocean water.

Upper-Level Divergence

Air spreading apart aloft that acts like a vacuum to pull surface air upward, lowering ground pressure to strengthen a storm cyclone.

Polar Front Theory

A meteorological theory developed by scientists Bjerkenes and Bergeron in Bergen, Norway, shortly after WW I.

Ordinary Cell Thunderstorm

A thunderstorm fueled by moisture, instability, and lift that typically lasts about $1$ hour and dissipates when the downdraft cuts off the updraft.

Gust Front

Also known as a cold pool, it is the leading edge of a thunderstorm's rain-cooled cold downdraft that surges outward along the ground.

Supercell Thunderstorm

A violent thunderstorm characterized by a deep, continuously rotating updraft called a mesocyclone.

Microburst

An intense downdraft created by the evaporation of rain in dry air, causing a heavy block of cold air to plummet downward and pose a hazard to aircraft.

Enhanced Fujita Scale

The scale used for classifying tornado intensity based on the damage the storm produces.

Cyclostrophic Balance

The force balance in small-scale vortices like tornadoes and dust devils where the pressure gradient force is balanced by centrifugal force rather than the Coriolis force.

Dryline

A boundary separating moist air masses from dry air masses, often observed across the plains.

Colorado Lows

Low-pressure systems that form in the lee of the Rocky Mountains and frequently move northeastward toward the Midwest and Great Lakes region, often passing over Chicago, IL.

NEXRAD

Current generation Doppler Radar used by the NWS that can depict mesocyclone rotation and tornadoes through radial velocity displays.

Vertical Stretching

A process in tornado formation where narrowing and lengthening a rotating column of air forces it to increase its rotational speed.