Unit 2: Weather

clouds seen during warm front

nimbostratus, altostratus, cirrostratus, cirrus

weather seen during warm front

moderate precipitation

clouds seen during cold front

cumulonimbus

weather seen during cold front

heavy precipitation

weather seen during occluded front

thunderstorms

clouds seen during stationary front

altocumulus

air mass

a large body of air defined by its temperature and humidity characteristics and bordered by fronts

front

boundary between 2 air masses of different temperatures or humidity that meet up

arctic

air mass from high latitudes

polar

air mass from mid latitudes

tropical

air mass from low latitudes

maritime

air mass from sea

continental

air mass from land

mP

maritime polar air mass

cT

continental tropical air mass

cold front pattern

blue triangles

warm front pattern

red scalloped

occluded front pattern

purple mixed shapes

stationary front pattern

red and blue mixed shapes

air pressure at sea level

14.7 psi

psi

pounds per square inch

atmospheric pressure is same as

barometric pressure

air pressure

the weight of the air above an object

why air exerts pressure

gas has mass

air flows from _ to _

high, low

air pressure decreases

elevation, temperature, humidity increases

why elevation decreases air pressure

fewer air molecules are above you

why temperature decreases air pressure

molecules spread out and become less dense

why humidity decreases air pressure

water vapor weighs less than nitrogen

high pressure system air direction

anticyclone, clockwise in north, down, out at ground

high pressure system weather

sunny

low pressure system air direction

cyclone, clockwise in south, up, in at ground

low pressure system weather

cloudy and rainy

what generates wind

air moving from high to low to equalize pressure

the closer lines in pressure gradient

the faster the winds

coriolis effect

direction of blowing wind is not in a straight line from high to low due to rotation of earth

what affects wind speed and direction

pressure gradient, friction, coriolis effect

In northern hemisphere wind deflects to

right

In southern hemisphere wind deflects to

left

orographic lifting

air is forced to rise over mountainous barrier so clouds form on the windward side of barrier

front wedging

warmer, less-dense air is forced over cooler, denser air

convergence

when air flows in from opposite directions, collides, and rises

local convective lifting

unequal surface heating causes localized pockets of air to rise because of their buoyancy

humidity

how much water vapor is in the atmosphere

isobar

lines on air pressure map that connect areas of equal pressure

pressure gradient

weather map that reports air pressure that looks like topographical map

monsoon

a wind systems that changes direction seasonally

altitude

how high up something is

hurricane

middle size of cyclone, in north atlantic and north east pacific

jet stream

fast flowing “river of air” at the top of the troposphere at boundary between P and T Air masses, goes east to west

tornado

smallest size of cyclone

sea breeze

cycle of a low pressure system above warm ground mixing with high pressure system above cool ocean

mid latitude cyclone

largest size of cyclone (is occluded front) (noreaster)

rain

snow falls into warm air and melts

freezing rain

snow melts in warm air but hits cold air and freezes on ground

sleet

snow melts and refreezes as it travels into cold air

snow

snow falls through cold air and never melts