Weather - Chapters 12, 13, 15, 16

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What is an air mass?: an extremely large body of air whose properties of temperature and humidity are fairly similar in any horizontal direction at any given altitude.
What air masses affect North America?: Continental Polar, Continental Arctic, Maritime Polar, Maritime Tropical, Continental Tropical.
Continental Polar and Continental Arctic: -bitterly cold weather in winter
-invades Southern Canada and US in winter.
-originate over the ice- and snow-covered regions of northern Canada and Alaska
-quite dry
-specific humidities less than 0.3 gram per kilogram
-usually brings relief from heat in summer
Maritime Polar: -originates over Asia and frozen polar regions
-warm and moisture filled air becomes cool, moist, and unstable
Maritime Tropical: -originates from the subtropical east Pacific Ocean
-warm and humid
Continental Tropical: -hot and dry
-originate in northern Mexico and the adjacent southwestern US
What is a front?: When two dissimilar air masses meet, they form a front
A transition zone between two dissimilar air masses
What are the different types of fronts?: warm front, cold front, occluded front, stationary front
Warm Front: a front that moves in such a way that warm air replaces cold air.
As cold air retreats, warm air also glides over cold air forming a ______ _______: gentle slope
gliding (rising) of warm air over cold air, called _____ _____, produces _____. It also creates temperature inversion called _______ ______: over running, clouds, frontal inversion
Warm air that seperates the two air masses has an average slop of _______: 1:300
precipitation falls ___________ of the front's surface boundary: in advance
precipitation from _______ clouds; light showers that last for _________ _______: nimbostratus, several hours
warm front moves _______: slowly
mostly not associated with:: tornadoes, hail, and lightning
Cold Front: a transition sone where a cold air mass advances and replaces a warm air mass
as warm air retreats, it is also forced to rise, forming a _______ ________: steeper slope
a cold front has an average slope of about ____: 1:50
this favors the development of ________ clouds: thunder-cumulunimbos
precipitation is _____, lasts for a _____ period: heavy, short
precipitation occurs where the front touches the _____: surface
_____ moves faster than _______: cold front, warm front
cold front may produce:: tornadoes, hail, thunder, lightning
occassionally, ahead of a fast-moving cold front, a line of active showers and thunderstorms called _________ decelop-producing strong gusty winds: "squall line"
Occluded Fronts: forms when faster-moving cold front overtakes a warm front
two types of occluded fronts: warm-type and cold-type
when the air behind the front is _____ than the air ahead of it, it is called a cold-type OC: colder
Stationary Front: develops when the surface position of a front does not move.
winds blow almost ________ and from _______ directions on each side of the front: parallel, opposite
what are middle latitude cyclones?: cyclonic storms in middle and higher latitudes
they are sometimes called:: wave cyclones, extratropical cyclones
they develop in _____: stages
what are the stages?: before storm (cyclogenesis or frontogenesis), early stage, mature stage (open stage), occluded stage, dissipation stage (dissolving stage)
before storm (cyclogenesis or frontogenesis) begins at the ______ ______: stationary front
before storm- wind blows almost _____ and from _____ directions on each side of the front: parallel, opposite
Early Stage- stationary front becomes _______: unstable
Early Stage- develops a wave called _____ ____ or ____ ____: frontal wave, incipient cyclone
early stage- region of _____ pressure is at the juncion of the two fronts: lowest
Mature stage (open stage)- frontal wave _______: intensifies
mature stage- develops into a _______ cyclone or ____ _____: mature, open wave
mature stage- mature cyclone can be _____ miles or moer in diameter: 500
mature stage- the region between the cold and warm fronts is called the ____ ____: warm sector
occluded stage- faster moving ____ front overtakes the _____ front: cold, warm
occluded stage - ___ air is lifted up from the surface: warm
occluded stage- the ___ pressure center shifts: low
Dissipation stage or dissolving stage- ______ eliminates surface warm air that provides energy for the cyclone: occlusion
dissolving stage- the cyclone ___ and ____: weakens and dissipates
dissolving stage - lifespan of a mid latitude cyclone ranges from ______ days: 1-5
what is a tropical cyclone?: an intense storm of tropical origin
types of tropical cyclones: hurricanes, typhoon, cyclone, baguios
where do these cyclones form?: hurricane- in US (N Amer)
typhoon - western pacific
cyclone- india, east africa, northern australia
baguios- philippine islands
a hurricane develops between ____ and ____ degrees of latitude: 5, 20
a hurricane develops over _____ _____: tropical oceans
hurricanes have surface water temps of _____ degrees or greater: 80
hurricanes will not form at the equator where ____ ____ is zero: coriolis force
hurricanes generally move ____ward with ___ ____: west, trade winds
hurricanes have isobars that are more _____, ____ and the ___ ____ is much steeper: circular, compact, pressure gradient
hurricanes derive their energy from the _____ _____ and _____ _____ of condensation released from the towering clouds: warm waters, latent heat
hurricane winds are strongest near the _______: surface
hurricanes usually develop an _____ where the air is _____: eye, sinking
_______ begins with convergence of surface winds: cyclogenesis
convergence develops a weak trouph of low pressuer called ______ _____, or ______ _______: easterly wave, tropical wave
on the eastern side of the axis, where surface winds converge, rising air generates _______ and _______: showers and thunderstorms
on its western side, where winds diverse, sinking air produces _______ _______: fair weather
hurrican stages of development: tropical disturbance, tropical depression, tropical storm, hurricane.
tropical disturbance: an organized mass of thunderstorms with a slight cuclonic wind circulation of less than 30 mph
tropical depression: a mass of thunderstorms and clouds generally with a cyclonic wind circulation between 30 and 39 mph
tropical storm: organized thunderstorms with a cyclonic wind circulation between 39 and 73 mph
hurricane: a severe tropical cyclone having winds in excess of 74 mph
the structure of a hurricane consists of:: the eye, and the eye wall
The eye occurs at the ____ of the storm: center
the eye may exceed _____ miles in diameter: 20
the eye has ____ sky or ____ clouds: clear, broken
the eye has ___ or ____ winds: calm or light
______ pressure is in the eye, about _____ mb with most sorms: lowest, 965
____ air aloft _____ into the eye, warming adiablatically: dry, descends
the eye wall is a ___ of intense _____: ring, thunderstorms
the eye wall ____ around the eye at the ____ speed: rotates, highest
the eye wall has ____ winds: strongest
winds in the eye wall ______ as they wirl around the eye: ascend
_____ ____ in the eye wall may read _____ to ______ miles from the surface: towering clouds, 6-9
thunderstorms are:: storms containing lightning and thunder
and estimated of ______ thunderstorms develop each day throughout the world. That's over ____ million annually: 40,000, 14 million
the majority of thunderstorms develop in _______ regions: tropical
in N. Amer., the majority of thunderstorms develop in ______ US: southeast
what are the two types of thunderstorms: air-mass thunderstorms and severe thunderstorms
air mass thunderstorms are ____ thunderstorms that form by _______: ordinary, convection
air mass thunderstorms are ______ thunderstorms that form in _____ in ______ latitudes: scattered, summer, middle
air mass thunderstorms form all year round in the ______: tropics
air mass thunderstorms are _____ ______ and rarely produce ____ ___ or ____ ___: short lived, strong winds, large hail
air mass thunderstorms develop in stages:: cumulus stage, mature stage, dissipating stage
in the cumulus stage of air mass thunderstorms the cloud is dominated by ______ and soon the could develops into a ______ _____: updrafts, cumulus congestus
in the cumulus stage of air mass thunderstorms there is no _____, ______ or ______: rain, lightening, thunder
in the cumulus stage of air mass thunderstorms, above _____ level, cloud particles ______ _____ and ____ and begin to fall: freexing, grow larger, heavier
in the mature stage of air mass thunderstorms, a ______ _____ cloud develops and ____ and ____ exist side by side: towering, intense, updrafts, downdrafts
in the mature stage of air mass thunderstorms there is ____ rainfall and occassionally small _____: heavy, hail
in the mature stage of air mass thunderstorms ______ are accellerated by the process called ______: downdrafts, entrainment
in the mature stage of air mass thunderstorms ___ air from around the cloud is drawn into the cloud and mixes with saturated cloudy air. This ____ the air and becomes ____: drier, chills, heavier
in the dissipating stage of air mass thunderstorms, updrafts _____, the cloud is dominated by _______, and there are light ____: weaken, downdrafts, showers
severe thunderstorms are capable of producing:: large hail stones larger than .75 inches in diameter, strong gusy surface winds over 58 mph, and tornadoes.
severe thunderstorms are usually assiciated with _____ Fronts and _____ cyclones: cold, tropical
downdrafts and updrafts in severe thunderstorms reinforce one another and ____ the storm: intensify
reinforcement in severe thunderstorms requires suitable conditions over an area from ____ to ____ km across. this area size is referred to as _____: 10 to 1000, mesoscale
this large area in a severe thunderstorm causes severe storms to appear in ___ or ___. Such clusters are called ______ ______ _____: groups or clusters, mesoscale convective systems (MCSs)
MCS's are also ____ ____: multicell thunderstorms
two basic types of multicell storms are:: mesoscale convective complex or MCC, and squall line thunderstorms
Mesoscale convective compex storms are ______ single-cell thunderstorms with a ___ appearance on an ____ satalite image.: muliple, circular, infared
Mesoscale convective compex storms are ______ lived storms that last for more than ____ hours and cover a ____ area: long, 6, wide
squall line thunderstorms are ____ storm cells arranged in a _____.: intense, line
squall line thunderstorms form ahead of a ____ front.: cold
supercell thunderstorms are enourmous ____ _____ storms.: single cell
supercell thunderstorms ______ and produce very damaging ______.: rotate, tornadoes
updrafts and downdrafts in supercell thunderstorms are ______.: tilted
In supercell thunderstorms, cold air of downdrafts forms the ____ ____ and produce extreme downdrafts called _______: gust front, downbursts
in supercell thunderstorms, there are strong, localized downdrafts less than ____ km in diameter beneath a storm called _______: 4, microburst
a supercell thunderstorm more than 4 km is a _______: macroburst
tornadoes are _____ of thunderstorms. The majority develop from ______ storms.: offspring, supercell
tornadoes have a diameter between _____ and ______ ft and have an average path of __ miles: 300, 8000, 4
The US experiences ___ tornadoes than any other coutry (over ____ annually): more, 1000
Tornadoes have occured in _____ state. The greatest # occur in the ____ ___ or ___ ___ of the central pains.: every, tornado belt, tornado ally
about ___% of tornadoes develp from ____ to ______ in teh US. ___ has the greatest # of tornadoes.: 75, march, july, may
the ____ ___ region is the most susceptible to tornadoes: central plains
What conditions lead to the formation of a tornado?: rotating updrafts with a severe thunderstorm called mesocyle and a funnel cloud
in the first mesocyclone stage, it rotates ____, ____, and _____: slowly, wider, and shorter
in the second stage of a mesocyclone, it stretches ______, _______, and rotates _____: vertically, narrows, faster
in teh thrid stage of a mesocyclone, it develops a ____ ___ at the cloud base called a ____ ___: dark cloud, wall cloud
in the fourth stage of a mesocyclone, the wall could ____ at the base of the cloud: protrudes
a ____ ___ develops from the protruding wall cloud: funnel cloud
a ___ ___ is issued when a funnel cloud is spotted: tornado warning
fujita scale for damaging wind: F0 AND F1 WEAK
F2 AND F3 STRONG
F4 AND F5 VIOLENT
about _____ of tornadoes in US fall into F0 or F1 category: 2/3
when a tornado occurs over water surface, a ____ ____ forms: water sprout
tornado alley includes 9 states:: texas, oklahoma, kansas, arkansas, missouri, nebraska, iowa, alabama, mississippi
Lightening: electrical discharge produced by mature storms
lightning may take place withing a ____, from one ___ to another, from cloud to surrounding ____, from cloud to _____: cloud, cloud, air, ground
lightning stoke heats the air to very high temps and the extreme heating causes air to expand ____, causing _____: explosively, thunder
cloud to ground lightening to occur, air between cloud ____ and ____ has to be _____ first: base, ground, ionized
cloud to ground lightening to occure, localized electricity field at cloud base ____ ____ in the air, ionizing teh air. this prepares a conductive path called _____ or ___ ____: frees electrons, leader, step leader
step leader is an initial discharge of _____ that proceeds intermittently in a series of steps. This is not visable to the human eye.: electrons
return stroke:: the luminous lightening stroke that propells upward from the earth to the base of the cloud
dart leader: re-ionizes the conductive path. it is continuous and less brached than a step leader

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