Chapter 21 Flashcards
Air moves from ___ pressure to ___ pressure.
high
low
a large body of air throughout which temperature and moisture content is similar
air mass
What are the four types of air masses?
cT
cP
mT
mP
What are the three tropical air masses?
Maritime tropical Pacific (mT),
Continental tropical (cT),
Maritime tropical Atlantic (mT)
What are the three polar air masses?
Maritime polar Pacific (mP),
Continental polar Canadian (cP),
Maritime polar Atlantic (mP)
the boundary between air masses
front
cold air mass pushes under a warm air mass like a wedge
cold front
What type of clouds form during a cold front?
large cumulus, cumulonimbus clouds
What happens during a fast-moving cold front?
large, violent thunderstorms
the line of heavy thunder storms
squall line
What happens during a slow-moving cold front?
weaker storms and light precipitation
warm air mass moves over a cold mass
warm front
What happens during a warm front?
gradual front slope, clouds spread ahead and cover a large area, precipitation covers large area, violent weather is occasionally caused
front of an air mass that moves very slowly or not at all
stationary
cold air mass moves under a warm air mass and lifts the warm mass completely off the ground
occluded
During a polar front cold air mass sits over each pole until about ___ degrees latitude.
60
air sinks and flows out from a high pressure center
anticyclone
bend that forms in a cold front or a stationary front
wave
areas of low pressure that are characterized by rotating wind, which moves toward the rising air of the center, low pressure region
midlatitude cyclones
Midlatitude cyclones usually last ___ days, travel at a speed of ___ km/h in a ___ direction, and spin ___.
several
45
easterly
counterclockwise
the boundary where cold air meets warm tropical air
polar front
Which direction do anticyclones spin in? Why? Where?
clockwise
because of the Coriolis effect
northern hemisphere
What do anticyclones bring?
dry, clear weather
What could happen if anticyclones stay too long?
they could cause pollution or drought
brief, heavy storms that have rain, strong winds, lightning and thunder
thunderstorms
What are the three stages of a thunderstorm?
- cumulus
- mature
- dissipating
What happens in the first stage of a thunderstorm?
Cumulus- warm, moist air rises, water vapor condenses and forms cumulus clouds
What happens in the second stage of a thunderstorm?
Mature- clouds rise and form cumulonimbus clouds, heavy rainfall and hail may fall, strong up and down drafts
What happens in the third stage of a thunderstorm?
Dissipating- downdrafts stop the fresh supply of water vapor from rising, clouds dissipate
the discharge of electricity
lightning
In lightning, the upper part of the cloud carries a ___ charge & the bottom carries a ___ charge.
positive
negative
Where are the three places lightning may form?
- inside a cloud
- between clouds
- between a cloud and the ground
How is thunder formed?
air around lightning super heats and expands rapidly, causing the loud noise
Lightning forms as electrons flow from ___ to ___ to ___ the charge.
positive
negative
equalize
A ___ is a tropical storm with wind speeds over ___ km/h that spiral around a ___-pressure storm center.
hurricane
120
low
What two things must a hurricane have to form?
- form over a warm tropical ocean
2. have the Coriolis effect
What is the process of a hurricane?
Warm, moist air rises and condenses, releasing energy as latent heat. Latent heat adds strength to rising air.
What is the eye of a hurricane?
came, clear sinking air
What happens during a fully-developed hurricane?
thick cumulonimbus cloud bands spiral around the center of the storm
What is the most destructive type of storm?
a hurricane
the rising sea level in front of a hurricane that causes flooding
storm surge
What are most hurricane deaths from?
drowning
rates hurricane intensity from 1-5
Saffir-Simpson scale
What three things does the Saffir-Simpson scale measure?
- central pressure
- wind speed
- storm surge
A ___ is a destructive, rotating column of air with very high wind speeds (up to ___ km/h).
tornado
400
What may a tornado be visible as?
a funnel-shaped cloud
smallest, most violent and short-lived storm
tornado
How does a tornado form?
when a thunderstorm meets high altitude horizontal winds that make it rotate
Texas through midwestern United States, tornadoes most common here from late spring to early summer
Tornado Alley
What are most tornado injuries/deaths caused by?
people in collapsed buildings, or
being struck by objects that are blown by the wind
a program designed to promote rapid exchange of weather information (it helps developing countries establish or improve their meteorological services)
World Weather Watch
What organization promotes the World Weather Watch? What’s its abbreviation?
The World Meteorological Organization (WMO)
What do weather maps allow meteorologists to do?
- understand current weather patterns
2. predict future weather events
What do meteorologists use to communicate weather data on a weather map?
symbols & colors
a pattern of meteorological symbols that represents the weather at a particular observing station and that is recorded on a weather map
station model
What does a station model show?
cloud cover, wind speed, wind direction, weather conditions, dew point, temperature, atmospheric pressure, and barometric tendency
Lines on weather maps connect points of ___ measurement.
equal
lines that represent equal temperature
isotherms
lines that represent equal pressure
isobars
What do closely spaced lines indicate?
a rapid change in pressure,
high wind speeds
What do widely spaced lines indicate?
gradual change in pressure,
low wind speeds
What is precipitation commonly shown with on a weather map?
colors/symbols
___ and ___ provide data that computers use to create weather models.
Doppler radar
satellite images
daily forecasts
48 hour range
extended forecasts
3-5 days
medium-range forecasts
3-7 days
long-range forecasts
7 days, monthly, seasonally
What is the goal of weather warnings?
to reduce the amount of destruction caused by severe weather, by forecasting severe weather early
issued when conditions are ideal for severe weather
Watch
issued when severe weather has been spotted (thunderstorms/tornadoes), or is expected within 24 hours (snowstorms/hurricanes)
Warning
What is the most researched method for producing rain?
cloud seeding
