weather and climate

exam 3 (ch.7)

convergent

air is flowing toward an area of low pressure

convectional

air is stimulated by local surface heating

frontal

air is displaced upward along the leading edges of contrasting air masses (cold and warm front)

orographic

air masses move laterally, pushed up and over mountain

windward

being in or facing the direction from which the wind is blowing. the wet side

leeward

The side of a mountain range that faces away from the oncoming wind. the dry side

rain shadow

Dry area on leeward side of mountains, where there is less rainfall.

air mass

A huge body of air that has similar temperature, humidity, and air pressure at any given height

mT

maritime tropical

mP

maritime polar

cT

continental tropical

cP

continental polar

weather

Short-term atmospheric conditions.

climate

The long-term average weather condition at a particular location

cold front

forms when cold air moves under warm air which is less dense and pushes air up (produces thunderstorms heavy rain or snow

warm front

the boundary of an advancing mass of warm air, in particular the leading edge of the warm sector of a low-pressure system.

occluded front

a front where a warm air mass is caught between two colder air masses and brings cool temperatures and large amounts of rain and snow

stationary front

cold and warm air masses meet but neither one advances

mid-latitude cyclones

large centers of low pressure that generally travel from west to east and cause stormy weather

easterly wave

a slow moving trough of low pressure that develops within the tropical latitudes

hurricane formation

they form in warm ocean waters

tropical cyclones

rotating storm systems originating over warm tropical waters

Thunderstorm Formation

a storm formed in cumulonimbus clouds. Most often in spring and summer

types of clouds

cirrus(wispy), cumulus(fluffy), stratus(flat), nimbus(thick(rain))

supercell

a powerful, rotating storm that is likely to spawn a tornado

multi cell

Clusters of thunderstorms that clump together

single cell

small and short-lived storms

tornado

small but powerful storm with very strong, whirling winds that may occur with a thunderstorm or hurricane

tornado watch

• the possibility that tornadoes may develop in a particular area during a specific time span

-- covers an area of 25,000 sq miles for a six hour period

tornado warning

A warning issued when a tornado has actually been sighted in an area or is indicated by radar.

Enhanced Fujita Scale (EF Scale)

a scale that uses the damage caused by the tornado to estimate the tornado wind speeds

funnel cloud

Swirling air beneath a cloud that becomes a tornado if it touches the ground.

lightning

the flashes of light that are produced in the sky during a storm

thunder

the sound caused by the rapid expansion of air along an electrical strike

lake effect

when lightning and thunder occur when cold air move over warmer lake water, triggering intense localized storms.