nights that are clear and calm than on nights that are cloudy and windy
The name given to a liquid drop of dew that freezes when the air temperature drops below freezing is
The cooling of the ground to produce dew is mainly the result of
For frozen dew to form,
all of the above, the air temperature needs to drop to freezing or below
Suppose it is a winter night and at about 10 p.m., the air cools to the dew-point temperature and a thick radiation fog develops. If the air continues to cool during the night, in 5 hours the dew point temperature will probably
decrease as the air becomes drier
Particles that serve as surfaces on which water vapor may condense are called
Frost forms when:
all of the above, when the dew point temperature is at or below freezing
On a humid day, ________causes salty potato chips left outside in an uncovered bowl to turn soggy.
the attraction of water by hygroscopic condensation nuclei
Frost typically forms on the inside of a windowpane (rather than the outside) because:
there is more water vapor touching the inside of the pane
Condensation nuclei may be:
particles of dust
Condensation nuclei are important in the atmosphere because:
without them, condensation would not occur easily in atmosphere
Under what circumstances could the relative humidity exceed 00 percent without producing fog?
there are no condensation nuclei present
Wet haze forms when the relative humidity is:
less than 100%
On a cold winter morning, the air near the surface is full of smoke particles. If fog should form in this air, it will probably ____ that forms in cleaner air.
be thicker than fog
High fog is also called
When radiation fog "burns off", the fog tends to dissipate:
from bottom up
When fog "burns off," it:
On a clear night, the minimum temperature drops to 34°F. The following night, fog forms early in the evening. It is a good bet the minimum temperature will not be as low because of the:
enhancement of the greenhouse effect by the fog cloud
Winter fog in the Central Valley region of California is mainly due to:
On a cold, winter morning, the most likely place for radiation fog to form is:
in a valley
The fog that forms along the Pacific coastline of North America is mainly which type?
Fog that forms off the coast of Newfoundland is mainly a form of
Along an irregular coastline, advection fog is more likely to form at the headlands than at the beaches because of the ____ surface winds and ____ air.
If fog is forming at Denver, Colorado, and the wind is blowing from the east, then the fog is most likely
Exhaled breath from your mouth can condense when
it is very cold
When you see your breath on a cold morning, the air temperature
can be above or below freezing
The use of helicopters to mix the air and disperse radiation fog at airports is effective provided that
the fog is a shallow radiation fog with a relatively low liquid water content
On a cold, calm autumn morning, the formation of fog above a relatively warm lake would most likely be
Which fog does not necessarily form in air that is cooling?
Frontal fog most commonly forms as ___ raindrops fall into a layer of ____ air
Fog that most often forms as warm rain falls into a cold layer of surface air is called
Clouds are classified by their
A reasonably successful method of dispersing cold fog is to
seed the fog with dry ice
Fog is a major hazard to aviation
Which association below is NOT correct?
altostratus- high cloud
At which city might you be able to observe cirrus clouds at an altitude of 3,000 m (0,000 feet) above the surface?
Even at high elevations where cirrus clouds are found, liquid water still exists in the clouds.
has a geostationary orbit- a circular geosynchronous orbit directly above the earths equator. Remain permanently fixed in exactly the same position in the sky.
observe clouds in earths orbit. Provides extremely valuable cloud photographs of areas where there are no ground-based observations.
Polar orbiting satellites:
closely parallel the earths meridian lines. Pass over the north and south polar regions on each revolution. Covers the entire earth
A rotating-beam ceilometer is useful for
estimating the altitude of the tops of vertical development clouds
Lenticular clouds typically form___a mountain range.
When temperatures are below freezing, the temperature to which air must be cooled in order for a phase change to occur is called the:
Dew, frozen dew, and frost form when the below-freezing layer of air is:
close to ground level
On humid days, salt in saltshakers sometimes becomes moist and no longer pours out easily. The salt can be described as:
Radiation fog typically forms on:
a clear winter night with a very slight breeze
In hilly areas, cold air typically collects:
When fog is "burning off," the cloud droplets are preventing solar radiation from reaching the ground.
Stratus and high fog are:
a uniform grayish cloud that often cover the entire sky. Resembles fog that does not reach the ground. Might be confused with nimbostratus.
Advection fog is often observed along the Pacific coast during summer, as westerly winds carry moist air toward the shore. The fog forms because the surface water near the coast is ____then surface water farther offshore.
Suppose two ocean currents with different temperatures are flowing next to one another. If the wind blows perpendicular to the currents, we would expect to find:
Upslope fog forms because air ___ as it flows up a hill or mountain range.
Suppose two unsaturated air masses mix horizontally. The resulting mixture cannot possibly be saturated
In order to be effective, fog lamps on cars should be directed:
Which two clouds can produce precipitation?
cumulonimbus and nimbostratus
Which of the following clouds are almost always composed of ice crystals?
Stratus clouds are typically puffy and form by convection.
Which below best describes the solute effect?
substances dissolved in a droplet can enhance or retard growth of the droplet
Which statement below best describes the curvature effect?
even if a cloud is at 100% relative humidity, small droplets can evaporate
Condensation onto hygroscopic nuclei is possible at relative humidities less than 100 percent due to the:
Which of the following is NOT an important factor in the production of rain by the collision-coalescence process?
the number of ice crystals in the cloud
Which cloud type below will only produce precipitation by the collision-coalescence process?
a thick, warm cumulus cloud
Large raindrops fall ____than smaller raindrops, and have a ___ terminal velocity than small raindrops.
Which cloud would most likely produce drizzle?
The merging of liquid cloud droplets by collision is called
If you observe large raindrops hitting the ground, you could probably say that the cloud overhead was ___ and had ___ updrafts.
If rain falls on one side of a street and not on the other side, the rain most likely fell from a:
During the ice crystal process of rain formation
ice crystals grow larger at the expense of the surrounding liquid cloud droplets
The temperature at which you would expect a cloud to become completely glaciated is
40 degrees C
Homogeneous nucleation occurs when:
randomly moving atoms form clusters above a critical threshold
When only ice crystals exist in a cloud, the cloud is said to be
Which of the following statements is NOT correct?
ice nuclei are more plentiful in the atmosphere than condensation nuclei
Ice nuclei may be:
ice crystals, certain clay minerals, bacteria in decaying plan leaf material
Supercooled cloud droplets are:
liquid droplets observed at temperatures below 0 deg C
At the same sub-freezing temperature, the saturation vapor pressure just above a liquid water surface is ____ the saturation vapor pressure above an ice surface.
Contact nucleation is:
involved in contact freezing. Can be just about any substance
The growth of a precipitation particle by the collision of an ice crystal (or snowflake) with a supercooled liquid droplet is called:
accretion or riming
Cloud seeding using silver iodide only works in
cold clouds composed of ice crystals and supercooled droplets
Which of the following conditions would be most suitable for natural cloud seeding by ice crystals?
a cirriform cloud lying directly above a lower cloud deck
What are the two main substances used in cloud seeding?
silver iodide and dry ice
After a rainstorm, visibility typically
Rain which falls from a cloud but evaporates before reaching the ground is referred to as:
The most common ice crystal shape:
Fall streaks usually ____ before reaching the ground.
Snowflakes or ice crystals falling from high cirriform clouds are called:
A light shower of snow that falls intermittently from cumuliform clouds for a short duration is known as
The creaking sound produced by walking on snow is most common on:
new snow when the air temperature is below -10 deg C
Which below best describes why a fluffy covering of snow is able to protect sensitive plants and their root systems from damaging low temperatures?
The largest snowflakes would probably be observed in ___ air whose temperature is ___ freezing.
In order for falling snowflakes to survive in air with temperatures much above freezing, the air must be ___ and the wet bulb temperature must be ____
unsaturated; at or below freezing
In the winter you read in the newspaper that a large section of the Midwest is without power due to downed power lines. Which form of precipitation would most likely produce this situation?
Which of the following might be mistaken for hail?
A raindrop or partially melted snowflake that freezes into a pellet of ice in a deep subfreezing layer of air near the surface is called
Which type of precipitation would most likely form when the surface air temperature is slightly below freezing and the air temperature increases as you move upward away from the ground?
The primary method used in preventing the growth of large, destructive hailstones is to inject a thunderstorm with large quantities of
Hail deposited in a long narrow band is known as a
Precipitation with the greatest size (diameter) is:
Glaze is another name for:
You would use a wooden stick to measure rainfall in the:
standard rain gauge
An amount of precipitation measured to be less than one hundredth of an inch (0.25 mm) is called:
If a city were to receive 1/2 inch of rain in the morning and then 5 inches of snow that afternoon, about how much precipitation would the weather service report for that day?
After a snowstorm, the newspaper reports that Buffalo, New York, received .50 inches of precipitation. If we assume an average water equivalent ratio for this snowstorm, then Buffalo received about __ inches of snow
On average, the water equivalent of 0 inches of snow is about __ inches of water
Radar gathers information about precipitation in clouds by measuring the:
amount of energy reflected back to the radar unit
In a typical advancing winter storm, which of the following sequences of precipitation types is most likely to occur?
rain, freezing rain, sleet, snow
Freshly fallen snow ___ sound waves.
The main difference between a cloud drop and a raindrop is its:
A typical raindrop is about ____ a typical cloud droplet.
a million times that of
Saturation vapor pressure ___ as temperature increases.
Large cloud droplets fall faster than small cloud droplets because
large drops have faster terminal velocity
The lightest form of rain is:
The difference in saturation vapor pressure between supercooled water and ice reaches a maximum at about -2°C. This means that the ice crystal process will be most effective in producing precipitation when cloud temperatures are:
below -40 degrees C
Satellites measure rainfall from space using which instrument?
Precipitation Radar and The microwave imager
Net convergence of air would cause surface pressure to increase and net divergence would cause surface pressure to
If the earth's gravitational force were to increase, atmospheric pressure at the ground would
The surface pressures at the bases of warm and cold columns of air are equal. Which of the following statements is NOT correct?
pressure will decrease with increasing height at the same rate in both columns
The surface pressures at the bases of warm and cold columns of air are equal. Air pressure in the warm column of air will ___ with increasing height ___ than in the cold column.
decrease; more slowly
Suppose a parcel of air has a given temperature, pressure, and density. If the parcel's size remains the same while its temperature increases, then the air pressure inside the parcel will:
If two air parcels at sea level have the same size but different temperatures, the colder parcel of air will have
the same pressure but higher density than the warm parcel
Which of the following relationships best describes the gas law
p= T x p x C
If surface air pressure decreases, the height of the column in a mercury barometer would:
If the outside air temperature is 27°C and the air density is .2 kg/m3, the outside air pressure would be:
The scale on an altimeter indicates altitude, but an altimeter actually measures:
A barograph will:
mark a continuous record of pressure on chart paper
The unit of pressure most commonly found on a surface weather map is
millibars or hectopascals
If a liquid with a lower density than mercury were used in a barometer, the height of the column in the barometer would
An aneroid barometer works on the principle that
a small closed cell with most of its air removed will expand and contract with changes in air pressure
Which of the following instruments measures pressure
An aneroid barometer carried from sea level to the top of a 300 m (,000 ft) hill would indicate:
The mercury barometer was invented by:
To obtain the station pressure you must normally make corrections for
temperature and gravity
A station at an altitude of 900 m (about 3,000 feet) above sea level measures an air pressure of 930 mb. Under normal conditions, which of the values below do you think would be the most realistic sea level pressure for this station?
Suppose a station at sea level measures an air pressure of 1,030 mb. Under standard conditions, what would be the most likely air pressure at an elevation of 600 m (about 2,000 ft) above this station?
To correctly monitor horizontal changes in air pressure, the most important correction for a mercury barometer is the correction for:
The surface weather map is a sea level chart. Thus, a surface weather map is also called
a constant height chart
Lines connecting points of equal pressure are called
more rapidly in the vertical direction than in the horizontal
On a weather map, ridges are
elongated high pressure areas
Which of the following expresses the gas law
p= T x p x C
According to the gas law, when temperature remains constant, which of the following is TRUE?
P= T rho C , rho 8 rho
Suppose you are a pilot who is flying from warm air into colder air. In the cold air, even though your altimeter is still indicating the same altitude as it did in the warm air, you would be flying:
lower than your altimeter indicated
On an isobaric surface,
the atmospheric pressure is everywhere equal
Low ___ on a constant height chart corresponds to low ___ on a constant pressure chart.
On a 500 millibar chart, ___ are drawn to represent horizontal changes in altitude which correspond to horizontal changes in pressure.
The contour lines drawn on a 500 mb chart are lines of constant:
If an airplane flies from standard temperature air into warmer than standard temperature air, without making any correction, the altimeter in the warmer air would indicate an altitude:
lower than the airplanes actual altitude
Warm air aloft is associated with constant pressure surfaces that are found at ___ altitude than normal and ___ than normal atmospheric pressure aloft.
On an upper-level chart, normally we find warm air associated with ___ pressure, and cold air associated with __ pressure
A surface low pressure center is generally associated with ___ on an upper level isobaric chart
On an upper-level chart the wind tends to blow
parallel to the isobars or contours
A ridge on an upper-level isobaric chart indicates
higher than average heights
On an isobaric weather chart, the spacing of the height contours indicates the magnitude of the pressure gradient force.
Newton's first law states that "an object at rest ___ as long as no force is exerted on the object."
will remain at rest
During a reversible adiabatic process, the pressure gradient force is parallel to the isobars
The Coriolis force is the force that causes the wind to blow.
The hydrostatic equation describes the equilibrium between the:
vertical pressure gradient force and gravity
Why is there a minus sign in the hydrostatic equation? (The hydrostatic equation is.)
as pressure decreases, height increases
The fundamental laws of motion were formulated by:
Sir Isaac Newton
The "force exerted on an object equals its mass times the acceleration produced" is a description of:
Newtons Second Law
Which of the following forces does not have a direct effect on horizontal wind motions?
Which of the following can influence wind direction?
coriolis force, pressure gradient, and centripetal force (all of these)
Which of the following forces CANNOT act to change the speed of the wind?
The net force on air moving in a circle at constant speed is
inward toward the center of rotation
The amount of pressure change that occurs over a given horizontal distance is called the:
Which of the statements below is NOT correct concerning the pressure gradient force?
it is non-existent at the equator
The pressure gradient force is directed from higher pressure toward lower pressure:
at all places on earth
The force that would cause a stationary parcel of air to begin to move horizontally is called the
pressure gradient force
Which of the following produces the strongest Coriolis force?
fast winds, high latitude
The ____ is an apparent force created by the earth's rotation
The rate of the earth's rotation determines the strength of the
The Coriolis force is the result of:
Which statement below is NOT correct concerning the Coriolis force
it causes the winds to blow faster
If the earth stopped rotating which of the following would NOT be true?
there would still be a Coriolis force
A wind blowing at a constant speed parallel to straight line isobars with the pressure gradient force (PGF) and the Coriolis force in balance is called a:
The net force acting on air which is blowing parallel to straight contours at constant speed is
to the right of the winds motion in the northern hemisphere
Suppose that the winds aloft are geostrophic and blowing from the north. Low pressure is located to the
Suppose that the winds aloft are geostrophic and blowing from the north. With the same orientation of isobars at the surface, the winds would blow from the:
The winds aloft in the middle latitudes would not blow from the west if
the air over high latitudes became warmer than over the equator
If in the Northern Hemisphere the upper level winds above you are blowing from the south, then it is a good bet that a trough of low pressure is to the
west of you
When the wind blows in a more or less west to east direction, the wind flow pattern is called:
A wind that blows at a constant speed parallel to curved isobars or contour lines is called a:
If directly above you at 10,000 feet the wind is blowing from the south, then it is a good bet that at 10,000 feet, the center of lowest pressure is left of you, while the center of highest pressure is ___ of you
A wind flow pattern that takes on a more or less north-south trajectory is called:
The vertical pressure gradient force is directed:
The winds aloft in the middle latitudes of the Southern Hemisphere generally blow
from west to east
A surface LOW pressure area that moves from south to north directly east of your home would most likely produce winds that shift from:
NE to N to NW
The wind around a surface low pressure center in the Southern Hemisphere blows:
clockwise and inward toward the center
Surface winds blow across the isobars at an angle due to:
the frictional force
If, at your home in the Northern Hemisphere, the surface wind is blowing from the northwest, then the region of lowest pressure will be to the ___ of your home.
Winds blow slightly inward:
around surface low pressure centers in the Northern and Southern hemisphere
Cyclonic flow means ___ in either the Northern or Southern Hemisphere.
circulation around a low pressure center
Buys-Ballot's law states that, "In the Northern Hemisphere if you stand with your back to the surface wind, then turn clockwise about 30°, lower pressure will be
to your left
The wind around a surface high pressure center in the Northern Hemisphere blows:
clockwise and outward from the center
We can generally expect the air to be ___ above areas of surface low pressure and __ above areas of surface high pressure.
The surface air around a strengthening low pressure area normally ___, while aloft, above the system, the air normally ___
The atmosphere around the earth would rush off into space if the vertical pressure gradient force were not balanced by
In the vertical, the pressure gradient force points ___ and gravity points ___
away from the earth; toward the earth
When the upward-directed pressure gradient force is in balance with the downward pull of gravity, the atmosphere is in:
If an air parcel is completely at rest, which of the following forces can make the parcel begin to move?
The smallest scale of atmospheric motion is the:
An example of mesoscale motion is:
winds blowing through a city
An example of microscale motion is
winds blowing past a chimney
Which of the following associations is most accurate?
mesoscale- land breeze
The slowing of the wind due to the random motion of air molecules is called
Thermal turbulence above the surface is usually most severe:
at the time of maximum surface heating
On a clear, windy day, the depth to which mixing occurs above the surface depends upon:
the wind speed, surface heating, and the landscape (all of the above)
The top of the friction layer is usually found near what altitude?
1,000 m (3300 ft)
The friction of fluid flow is called:
Surface winds are generally strongest and most gusty:
in the afternoon
The wind's speed generally increases with height above the earth's surface because:
friction with the earths surface slows the air near the ground
The howling of wind on a blustery night is believed to be caused by
eddies of higher air density
An abrupt change in wind speed or wind direction is called
Violent, rotating eddies that create hazardous flying conditions beneath the crest of a mountain wave are called
Clear Air Turbulence (CAT) can occur
when huge eddies develop in clear air
Which below is NOT true concerning an "air pocket"?
they often form in regions that exhibit strong vertical wind shear
Pedaling a bicycle into a 20 knot wind will require about ___ as much effort as pedaling into a 10 knot wind.
The greatest wind speed ever recorded at the earth's surface occurred at
231 mhp in 1934 on Mount Washington, New Hampshire
Clear air turbulence often occurs near a boundary of high wind shear
The size and shape of a turbulent eddy depend on
the size of the obstacle, the shape of the obstacle, and the speed of the wind (all of these)
Suppose the wind speed increased from 5 mph to 10 mph. We can conclude that the force exerted by the wind increased by a factor of
If huge waves pound against the beach communities of Southern California for several days during clear, calm weather, it is a good bet that
the winds are strong somewhere over the Pacific ocean
Suppose the wind speed increased from 5 mph to 25 mph. We can conclude that the force exerted by the wind increased by a factor of
Which of the features below could indicate prevailing wind direction
(all of the above)
Dust storms and dust devils are ___ on Mars
A wind rose indicates:
the percentage of time that the wind blows from different directions.
The most practical location for building a wind turbine would be:
regions with moderate, steady winds
An offshore wind:
is wind blowing from land to water, ex. land breeze
Which below would NOT be considered an onshore wind?
Santa Ana wind
A wind reported as 45° would be a wind blowing from the
Suppose a west wind of 20 knots blows over a coastal region which is densely covered in shrubs. If this same wind moves out over the middle of a large calm lake, its speed and direction would probably be:
greater than 20 knots and more northwesterly.
What instrument would you use for a rawinsonde observation?
An instrument used to measure wind speed is called a(n):
A wind reported as 225° would be a wind blowing from the
A wind profiler obtains wind information using
Doppler radar and the backscattered energy
A wind instrument that usually consists of three or more cups
The instrument that uses infrared or visible light in the form of a laser beam to determine wind direction is the:
Which of the instruments below indicates both wind speed and wind direction?
Which instrument only measures wind speed?
Which is NOT a characteristic of a thermal low?
becomes stronger with increasing height
If the sea level pressure in Philadelphia, Pennsylvania is 1016 mb, the strongest summertime sea breeze along the New Jersey coast would occur when the sea level pressure just east of Atlantic City, New Jersey is:
During the summer in humid climates, nighttime clouds tend to form over water during a:
Which below is usually NOT true concerning a sea breeze circulation?
they mainly occur at night
A sea breeze circulation will reverse direction and become a land breeze
once per day
A sea or land breeze is caused by:
differences in temperature
The nighttime counterpart of the sea breeze circulation is called a:
In summer, during the passage of a sea breeze, which of the following is NOT usually observed?
a drop in relative humidity
A smog front is most often associated with which wind system
A cool, summertime wind that blows from sea to land is called a
When a sea breeze moving north meets a sea breeze moving south, they form a
cloudy conditions and showery weather over the land
Clouds and precipitation are frequently found on the downwind side of a large lake. This would indicate that the air on the downwind side is
converging and rising
During the summer along the coast, a sea breeze is usually strongest and best developed:
in the afternoon
Monsoon depressions are
low pressure areas that enhance rainfall during the summer monsoon.
The summer monsoon in eastern and southern Asia is characterized by:
wet weather and winds blowing from sea to land
An extremely strong downslope wind that occurs in parts of Antarctica would be considered a:
The winter monsoon in eastern and southern Asia is characterized by
dry weather and winds blowing from land to sea
Low pressure becomes best developed over the Asian continent in
While fly fishing in a mountain stream, you notice that the wind is blowing upstream. From this you could deduce that the wind is a:
Cumulus clouds that appear above isolated mountain peaks are often the result of:
A valley breeze would develop its maximum strength
in early afternoon
A strong, usually cold, downslope wind is called a
A katabatic wind on the Oregon coast would most likely blow from the:
east to west downslope
A katabatic wind is a ___ wind
A chinook wind in the Alps is called a:
The heat from a chinook wind is generated mainly by:
A chinook wall cloud is a:
bank of clouds forming over the mountains
On the eastern side of the Rocky Mountains, chinook winds are driest when:
clouds form and precipitation falls on the upwind side of the mountains
Chinook winds are
warm, dry winds that descend the eastern slope of the Rocky Mountain
The main reason Santa Ana winds are warm is because:
sinking air warms by compression.
Santa Ana winds warm by ___ as the flow down an elevated desert plateau.
The Santa Ana wind is a ___ wind that blows into southern California.
Strong Santa Ana winds develop in Los Angeles during the fall when a ___pressure center forms to the
high; northeast of Los Angeles over the Great Basin
A warm, dry gusty wind that blows across North Africa is the:
Which of the following conditions favor the development of dust devils
hot, dry days
Another name for a small, rotating whirlwind observed at the surface is:
A dust or sandstorm that forms along the leading edge of a thunderstorm is a
A northeaster along the east coast of the United States is best developed when a low pressure area:
enhances the surrounding pressure gradient
A sea breeze is most likely to develop along a coastline when
large temperature differences exist between land and water
Which of the following is a serious hazard to aircraft
Good hang-gliding conditions require:
Strong winds blowing over vegetation results in:
If the wind speed doubles, the force exerted by the wind increases by a factor of
The land/sea breeze, lake breeze, and mountain/valley breeze are examples of:
A seiche can be caused by:
strong winds and sudden changes in atmospheric pressure or by earthquakes
A westerly wind means that the atmosphere:
is moving faster than the earth spins
Which below is NOT an assumption of the single-cell model of the general circulation of the atmosphere?
the earth rotates once in 24 hours
The large thermally driven convection cell that is driven by convective "hot" towers along the equator is the
Air moving eastward more slowly than the earth rotates, would appear to be ___ wind to an observer on the earth.
Chicago, Illinois (latitude 42°N) is located in the
The intertropical convergence zone (ITCZ) is a region where:
northeast trades meet the southeast trades
In terms of the three-cell model of the general circulation, areas of surface low pressure should be found at:
the equator and 60 degree latitude
In Honolulu, Hawaii (latitude 2°N), you would most likely experience winds blowing from the:
At Barrow, Alaska (latitude 70°N), you would expect the prevailing wind to be
Generally, along the polar front, one would not expect to observe:
sinking air aloft
According to the three-cell general circulation model, at the equator we would not expect to find:
a ridge of high pressure
The wind belt observed on the poleward side of the polar front is called the
On a weather map of the Northern Hemisphere, one would observe the westerlies
between the subpolar lows and the subtropical highs
The majority of the United States lies within which wind belt
On a weather map of the Northern Hemisphere, the trade winds would be observed:
south of the subtropical highs
In the general circulation of the atmosphere, one would find the region called the doldrums:
at the equator
In terms of the three-cell general circulation model, the driest regions of the earth should be near:
30 degrees latitude and the polar regions.
The world's deserts are found at 30° latitude because
of the sinking air of the subtropical highs
On a surface weather map during the month of July, one would expect to find what type of pressure system over the desert southwest of the United States?
The semi-permanent pressure systems associated with the polar front are called:
Which of the following is not considered a semi-permanent high or low pressure area?
The position of the Pacific high over the North Pacific Ocean shifts ___ in winter and ___ in summer.
The large semi-permanent surface anticyclone that is normally positioned over the ocean, west of California, is called the:
A thermally direct cell is one that:
is driven by energy from the sun
Many small-scale processes are ___ in General Circulation Models.
approximated and parameterized
Which of the following does NOT describe the subtropical jet stream?
forms along the polar front
Which below does NOT describe the polar front jet stream
is normally found at a higher elevation than the subtropical jet
In the Northern Hemisphere, the polar jet stream is strongest when:
air north of the polar front is much colder than air south of the polar front.
The jet stream flows:
in a wavy pattern from west to east
As an air parcel aloft moves northward from the equator, it moves closer to the earth's axis of rotation. Because of the conservation of angular momentum, the air parcel's motion should:
increase in speed
In the Northern Hemisphere, air found to the north of the polar front is cold, while air further south is
The average winds aloft are strongest in:
The low-level jet that forms over the Central Plains of the United States appears to be responsible for:
Factors that contribute to the formation of a low-level jet stream over the Central Plains of the United States are:
the sloping of the land from the Rockies to the Mississippi Valley, a north-south trending mountain range, stable air above the jet ( all of these)
Which below is NOT correct about the stratospheric polar-night jet stream?
it is found near the tropopause.
Generally, on an upper-level (100 mb) chart in the Northern Hemisphere during July, we would expect to find the tropical easterly jet stream:
south of the upper-level subtropical high
A phenomenon in the Atlantic Ocean, similar to the southern oscillation, is the
North Atlantic Oscillation
Average winter temperatures in Great Britain and Norway would probably be much colder if it were not for the:
North Atlantic Drift
In the Northern Hemisphere, ocean currents in the Atlantic and the Pacific move in a generally circular pattern. The direction of this motion is ___ in the Atlantic and ___ in the Pacific.
The Pacific Decadal Oscillation is similar to the El Niño/Southern Oscillation, except that it:
affects fish populations
At any given time, only one jet stream can be found in the atmosphere.
The cold water observed along the northern California coast in summer is due mainly to:
Major ocean currents that flow parallel to the coast of North America are
California, Gulf Stream, Labrador
The name given to the current of warm water that replaces cold surface water along the coast of Peru and Ecuador during December is:
The two ocean currents, warm and cold, that produce fog off the coast of Newfoundland are the:
Gulf stream and Labrador current
The turning of water with depth is known as:
the Ekman Spiral
The Ekman Spiral describes:
the turning of water with depth
the rising of cold water from below
During a major El Niño event
extensive ocean warming occurs over the tropical Pacific
At jet streak is a place where ___is (are) often found.
clear air turbulence, strong vertical wind speed shear, very strong winds (all of these)
Upwelling occurs along the northern California coast because:
winds cause surface waters to move away from the coast
A condition where the central and eastern tropical Pacific Ocean turns cooler than normal is called:
The reversal of the positions of surface high and low pressure at opposite ends of the Pacific Ocean is called:
the Southern Oscillation
If the earth's surface was homogeneous (either all land or all water
the semipermanent highs and lows wouldnt change in intensity
Because clouds often block their view, instruments onboard satellite cannot regularly make observations of surface winds.
The scatterometer measures winds by sending and receiving pulses of
Satellites provide a global picture of winds by converting ____ into wind speed and direction.
During some years, the northern hemisphere has more than 10 semi-permanent highs and lows.
The southern hemisphere has ___semi-permanent lows than the northern hemisphere.
Areas of rising air tend to be associated with ___ precipitation.
Jet streams sometimes split into two branches.
A jet stream transfers more heat across the globe when it is:
The ultimate cause of jet streams is:
the energy imbalance between high and low latitudes.
During the positive phase of the North Atlantic Oscillation,
an increased pressure gradient exists across the North Atlantic Ocean, the prevailing westerlies in the northern hemisphere are stronger, winters in the eastern US are wet and mild, (all of these)
A good source region for an air mass would be:
generally flat areas of uniform composition with light surface winds
The origin of cP and cA air masses that enter the United States is
Northern Canada and Alaska
Continental polar (cP) and continental Arctic (cA) air masses
originate over the ice- and snow-covered regions of the arctic, northern Canada, and Alaska where long, clear nights allow for strong radiational cooling of the surface.
Which of the following statements is most plausible?
In winter cA source regions have lower temperatures than cP source regions
The temperature that unsaturated air would have if it moved from its original altitude to a pressure of 1,000 mb is the:
In an exceptionally cold winter during which the Great Lakes were entirely covered by ice, lake effect snows would be expected in extremely high frequency and intensity.
Compared to an mP air mass, mT air is
warmer and moister
A moist, tropical air mass that is warmer than the surface over which it is moving would be classified
The greatest contrast in both temperature and moisture will occur along the boundary separating which air masses?
mT and cP
An air mass is characterized by similar properties of ___ and ___ in any horizontal direction.
One would expect a cP air mass to be:
cold and dry
A Texas norther (or blue norther) is most often associated with which air mass?
When cP air moves into western Washington, western Oregon, and California from the east, the air mass is warmer at the surface than it was originally because:
the air sinks, is compressed, and warms
Which air mass would show the most dramatic change in both temperature and moisture content as it moves over a large body of very warm water?
Continental Polar (cP) in winter
The coldest of all air masses is
What type of air mass would be responsible for refreshing cool, dry breezes after a long summer hot spell in the Central Plains?
Record breaking low temperatures are associated with which air mass?
Clear sunny days with very cold nights would be associated with what type of air mass?
Cumuliform cloud development would be most likely in which of the following
cP air mass moving over warm water
Lake-effect snows are best developed around the Great Lakes during:
late fall and early winter when cold, dry polar air moves over the relatively warm water
The lake effect occurs when a ___ air mass moves over a ___ body of water.
Generally, the greatest lake effect snow fall will be on the ___ shore of the Great Lakes.
During the winter, an air mass that moves into coastal sections of Oregon and Washington from the northwest would most likely be
Wintertime mP air masses are less common along the Atlantic coast of North America than along the Pacific coast mainly because:
the prevailing winds aloft are westerly
The designation for a cool, moist air mass is
What type of air mass would be responsible for snow showers on the western slopes of the Rockies?
What type of air mass would be responsible for persistent cold, damp weather with drizzle along the east coast of North America?
What type of air mass would be responsible for hot, muggy summer weather in the eastern half of the United States?
The air mass with the highest actual water vapor content is
In Southern California, which air mass is mainly responsible for heavy rains, flooding in low-lying valleys, and melting of snow at high elevations
During the spring, which air mass would most likely bring record-breaking high temperatures to the eastern half of the United States?
What type of air mass would be responsible for daily afternoon thunderstorms along the Gulf Coast?
What type of air mass would be responsible for heavy summer rain showers in southern Arizona?
An mT air mass lying above a cold ground surface represents a(n) ___ situation
What type of air mass would be responsible for summer afternoon thunderstorms along the eastern slopes of the Sierra Nevada Mountains in California?
Which air mass forms over North America only in summer?
What type of air mass would be responsible for hot, dry summer weather in southern Arizona?
A maritime polar air mass that reaches the Pacific Coast is:
Cool, Moist, and Conditionally Unstable
During winter, easterly winds along the front range of the Rocky Mountains provide excellent conditions for:
Along the boundary between continental polar and maritime tropical air masses, ___is often found
widespread precipitation and strominess
On a weather map, the transition zone between two air masses with sharply contrasting properties is marked by:
The word "frontogenesis" on a weather map would mean that
a front is regenerating or strengthening
Continental tropical air masses are typically found in:
northern Mexico and the southwestern US
Fronts are associated with:
The only indication on the station model of past weather conditions is the
A drylines is:
a dew point front and a boundary marking a strong horizontal change in atmospheric moisture
An upper-air front involves downward motion of the:
When comparing an "average" cold front to an "average" warm front, which of the following is NOT correct?
generally, precipitation covers a much broader area with a cold front
Alternating lines of blue and red on a surface weather chart indicate:
a stationary front
A stationary front does not move because:
the winds blow parallel to the front
A true cold front on a weather map is always:
followed by cooler air
Which of the following is NOT correct concerning a cold front?
it is colored purple on a weather map
On a weather map, this front, drawn in blue, represents a region where colder air is replacing warmer air:
Before the passage of a cold front the pressure normally falls, and after the passage of a cold front the pressure normally
Squall lines most often form ahead of a
In winter, thunderstorms are most likely to form along:
A "back door" cold front moving through New England would most likely have winds shifting from ___ to ___
A "back door" cold front describes which of the following situations?
a cold front that moves into New England from the Atlantic Ocean
A cold front that moves into New England from the east or northeast is called
a "back door" cold front
Which of the following is NOT correct concerning a warm front?
it has warm air ahead (in advance) of it
A halo around the sun or moon indicates that rain may be on the way because the halo indicates:
a warm front may be approaching
A frontal inversion would probably be best observed
with a warm front in winter
In winter, which sequence of clouds would you most likely expect to observe as a warm front with precipitation approaches your location?
cirrus, cirrostratus, altostratus, nimbostratus
The rising of warm air up and over cold air is called
At a warm front, the warm air
rises and cools
During the winter as you travel toward a warm front, the most likely sequence of weather you would experience is:
snow, sleet, freezing rain, rain
On a weather map where cold air is replacing cool air, what type of front is drawn?
cold-type occluded front
Occluded fronts may form as
a cold front overtakes a warm front
A cold-type occluded front:
has cold surface air behind it
What type of weather front would be responsible for the following weather forecast? "Increasing cloudiness and warm today with the possibility of showers by this evening. Turning much colder tonight. Winds southwesterly becoming gusty and shifting to northwesterly by tonight."
What type of weather front would be responsible for the following weather forecast? "Increasing high cloudiness and cold this morning. Clouds increasing and lowering this afternoon with a chance of snow or rain tonight. Precipitation ending tomorrow morning. Turning much warmer. Winds light easterly today becoming southeasterly tonight and southwesterly tomorrow."
What type of weather front would be responsible for the following weather forecast? "Increasing high cloudiness and cold this morning. Clouds increasing and lowering this afternoon with a chance of snow or rain tonight. Precipitation ending tomorrow morning. Turning much warmer. Winds light easterly today becoming southeasterly tonight and southwesterly tomorrow."
What type of weather front would be responsible for the following weather forecast? "Cool today with rain becoming heavy by this afternoon. Slightly warmer tomorrow. Winds southeasterly becoming westerly to northwesterly by tomorrow morning."
warm-type occluded front
What type of weather front would be responsible for the following weather forecast? "Light rain and cold today with temperatures just above freezing. Southeasterly winds shifting to westerly tonight. Turning colder with rain becoming mixed with snow, then changing to snow."
cold-type occluded front
The polar front theory of a developing wave cyclone was conceived in
Which of the scientists below was not one of the meteorologists who helped develop the polar front theory of a developing wave cyclone?
On a surface weather map that shows an open wave cyclone, the warm sector can be observed:
ahead of an advancing cold front
According to the model of the life cycle of a wave cyclone, the storm system is normally most intense:
when the system first becomes occluded
Which below is not a name given to a large cyclonic storm system that forms in the middle latitudes?
In the polar front theory of a developing wave cyclone, energy for the storm is usually derived from all but which of the following?
heat energy stored in the ground
Another term for explosive cyclogenesis used by meteorologists is
The development or strengthening of a middle latitude storm system is called:
Which region is not considered to be a region where cyclogenesis often occurs?
A building anticyclone means:
the central pressure is increasing
For cyclogenesis to occur along a frontal wave, the winds aloft directly above the wave should be:
The piling up of air above a region is called:
If the flow of air into a surface low pressure area is greater than the divergence of air aloft, the surface pressure in the center of the low will
Which of the following is NOT associated with rising air motions?
convergence of air aloft
Cyclogenesis is the ____of a mid-latitude cyclone.
development or strengthening
A lee-side low forms:
on the downwind side of a mountain
Northeasters (or nor'easters) are midlatitude storms commonly found:
along the Atlantic coast of North America
A surface low pressure area with a deep upper-level trough to the west will tend to move toward the:
When a deep upper-level trough is located to the east of a surface anticyclone, the surface anticyclone will tend to move toward the:
When an upper-level low lies directly above a surface low, the
the surface low will probably weaken
An upper-level pool of cold air that has broken away from the main flow is called
a cut-off low
For a surface storm system to intensify, the upper-level low (or trough) should be located to the ___ of the surface low.
Developing low pressure areas generally have ___ air near the surface and diverging air aloft.
Strong storms that develop over water, poleward of the polar front, are called:
Like hurricanes, polar lows have a clear area in their center
When upper-level divergence of air above a surface low pressure area is stronger than the convergence of surface air, the surface pressure will ___ and the storm itself will ___
If the outflow of air around a surface high pressure area is greater than the convergence of air aloft, you would observe:
a decrease in the central pressure
Longwaves in the middle and upper troposphere usually have lengths on the order of:
thousands of kilometers
An upper-level trough that shows retrograde motion would probably be moving toward the:
Rossby waves are also known as:
Atmospheric shortwaves usually move ___ at a speed that is ___ than longwaves.
west to east; faster
Atmospheric shortwaves usually move ___ than longwaves, and ___ when they move through a longwave ridge.
A small, moving disturbance imbedded in a longwave is called:
On an upper-level chart where the isotherms cross the isobars (or contours) and temperature advection occurs, the atmosphere is called:
During baroclinic instability,
wave cyclones can intensify into large storm systems, strong wind speed shear exists from the surface up to at least the 500 mb level, rising and descending air motions exist, temperature advection is occurring (all of these)
Which of the following statements is NOT correct about vorticity?
the earths vorticity is zero at the poles
If we assume that the absolute vorticity of flowing air is conserved, air moving northeastward will bend ___ to compensate for the ___ in the earth's vorticity.
Lee-side lows are
storms (extratropical cyclones) that form on the eastern (lee) side of a mountain range
The planetary vorticity of an air parcel moving from low toward high latitude in the Northern Hemisphere will:
Vorticity refers to:
the spin of air parcels
The type of weather system known as a 'mid-latitude cyclone' CANNOT form over the tropical ocean because:
surface temperature contrasts are not large and the Coriolis force is weak in the tropics