WEATHER The state of the atmosphere and its short term variations as defined by various weather elements, most notably, temperature, wind, humidity, cloudiness, visibility and precipitation, and storminess.

Condensation

• The process by which water vapor cools and becomes a liquid.

Weather Symbols

• The state of the atmosphere at a given time and place, with respect to variables such as temperature, moisture, wind velocity, and barometric pressure

Water Vapor • water in the gaseous state caused by

evaporation

Evaporate • when the sun heats up liquid surface water and turns

it into gaseous water vapor. The water vapor rises and becomes part of the atmosphere

Water • Water vapor is water in its gaseous state-

instead of liquid or solid (ice). Water vapor is totally invisible. If you see a cloud, fog, or mist, these are all liquid water, not water vapor.

Clear Skies

• Sky with no cloud cover

Moderate temperature

• Not extremely hot or cold, temperature with in a mild range

The force that pulls objects toward

each other

Gravity

Tropical Waters

• Ocean waters within 23 degrees latitude of the equator. In the western Atlantic, these waters are warm year-round. When a hurricane is moving through these waters, it is considered a tropical cyclone.

Precipitation

• water that falls to the ground as rain, snow. sleet, or hail

Severe Weather

• any dangerous meteorological phenomena with the potential to cause damage, serious social disruption, or loss of human life such as hurricanes or tornadoes

Ocean Water

• The salt water in or coming from the sea or ocean. Ninety seven percent of our water is saltwater.

Thunderhead • a cumulonimbus cloud seen during a

thunderstorm

CLIMATE The composite pattern of long-term weather conditions that can be expected in a given region. Climate refers to yearly cycles of temperature, wind, rainfall, etc., and not to daily variations (see "weather").

HIGH PRESSURE

Air Pressure System

Cause

Weather associated with

this pressure system

High Pressure (H)

Cool, sinking air moving in

a clockwise direction

Dry, clear weather

LOW PRESSURE

Air Pressure System

Cause

Weather associated with

this pressure system

Low Pressure (L)

Warm, rising air moving in

a counterclockwise

direction

Moist air, clouds, rain,

possible thunderstorms

and tornadoes

WARM FRONT (air mass/air front)

Warm air replaces cooler air. Light to moderate rain; warmer more humid temperatures after frontal passage

COLD FRONT (air mass/air front)

Advancing cold air replaces warm air. Frequent rain with possible thunderstorms. Cooler temperature and drier air after frontal passage.

TORNADOES

The shaking of Earth’s crust caused by rock slabs moving against each other.

Earthquake

HURRICANE Seasonal storm that usually forms from low pressure areas over the warm (over 80°), tropical ocean waters of the western Atlantic

A large wave produced by an earthquake,

volcano, or landslide

Tsunami

OCCLUDED FRONT A warm front is overtaken by a cold front. Severe snowstorms in the northeastern United States.

STATIONARY FRONT Air masses on either side of the boundary are not moving or are barely moving. Cloudy, overcast, some light showers or drizzle. Conditions do not change until another system moves through.

JETSTREAM A(n) jet stream is a narrow band of high winds that are commonly near the top of the troposphere. -Jet streams flow from the west at up to 300 km/h, pushing weather systems from W to E in the United States.

PREVAILING WINDS

SEA BREEZE

LAND BREEZE

HUMIDITY The amount of water vapor (gas) in the air. Measured in grams of water per cubic meter of air. Tool – psychrometer

MARITIME POLAR AIR MASS Where are they from - over northern Atlantic and Pacific Oceans

Characteristics - contain cold, humid air; often bring cloudy, rainy weather

CONTINENTAL TROPICAL AIR MASS

Where are they from - over dry deserts near the equator

Characteristics - contain hot, dry air; bring clear skies and high temperatures

MARITIME TROPICAL AIR MASS

Where are they from - over water near the equator Characteristics - contain hot, humid air; often bring rain or snow

CONTINENTAL POLAR AIR MASS

Where are they from - in polar regions in the interior of Canada and Alaska Characteristics - contain cold, dry air; bring cold temperatures in winter and cool weather in summer

CONDUCTION the transfer of energy from one molecule directly to another

CONVECTION Transfer of energy through a fluid. Hot fluids rise, cold fluids sink.

EL NINO warm ocean current appearing annually around Christmas time along the coast of Ecuador and Peru and lasting only a few weeks to a month or more.

Equator