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A cloud that forms liquid droplets has a relative humidity of 100 percent with respect to the liquid droplets. If ice crystals form in this cloud, they will experience the cloud environment as having a relative humidity
Where are lenticular clouds most likely form?
on the lee side of mountains; they form whenever the airflow undulates sharpley in the veritcal.
The important difference between liquid droplets and ice crystals in a supercooled cloud is that ice crystals
grow much more rapidly
The conditions that persist along the West Coast of the U.S. that are conducive to fog formation are
Moist air moving over a cold surface
What is the basic reason why condensation is not very important in cuasing a cloud droplet to grow to a raindrop size?
Condensation is too slow
The raindrops that fall to Earth from a warm cloud contain about one million times the water in a typical cloud droplet. This growth from cloud droplet to raindrop occurs mainly because of
Collision and Coalescence
Clouds, dew and frost all form because air has become saturated. This condition of saturation is usually caused by
Air being Cooled
Which type of fog occurs during nights when skies are clear and relative humidity is high?
Salt, dust particles, silver iodide, and combustion by-productions are all examples of
Hydrostatic Equilibrium is best defined as
an upward directed vertical pressure gradient, which is usually balanced by gravity.
Meteorologists convert all atmospheric pressure data to the equivalent sea-level air pressure in order to
remove the effects of elevation
The best explanation for the cause of atmospheric pressure is
Gravity. Atmospheric pressure is the weight of a column of air. Of course, the temperatuer of that air changes its density and therefore its weight.
The pressure gradient force is directed from higher to lower pressure
this force is called the pressure gradient force
The term pressure gradient refers to
the spacing of the isobars which indicates the amount of pressure change occurring over a given distance
When density remains constant and the temperature is lowered, the pressure of a confined gas
Why do surface winds cross the isobars at an angle toward lower pressure?
because of Frictional Force
According to Hadley, the most important factor causing circulation patterns in the atmosphere was
Temperature contrasts between the equator and pole
Concerning rainfall patterns, areas of persistent high pressure tend to cause
desert regions. This is because high pressure systems have sinking mechanisms, which prevent the formation of clouds and precipitation.
a CT air mass is
Continental Tropical Air; source region for cT air is the desert southwest. Skies are usually clear. This allows daytime heating during the day and radiational cooling at night.
An air mass is a body of air with
Characteristics of temperature, moisture, and pressure that are approximately uniform horizontally.
An mP air mass is
Maritime Polar; The source region for mP air is over cold ocean currents or high latitude ocean waters. Not much moisture content as cT air.
Characters of an air mass source region include
the location where the different types of air masses formed. Generally very large. Example: Ocean
Compared to continental air masses with the same air temperature, maritime air masses:
Continental tropical air masses form over tropical or subtropical water, resulting in their warm temperature. Maritime forms over Polar regions
The two most important properties that should be relatively homogeneous at the same altitude in an air mass are
Temperature and amount of moisture at any given altitude.
Which region of origin for mT air masses has the most impact on North American weather?
As a warm front approaches, which progression of clouds are you most likely to see
cirrus, altostratus, stratus, nimbostratus
The more violent nature of weather produced by a cold front can be attributed to which two factors
Steep slope, fast forward motion of front
Why is the number and intensity of wave cyclones greatest during the late fall, winter, and spring months
Temperatures are below freezing
Which of these best describes the reason most high pressure systems bring clear skies?
sinking air aloft
Compared to other types of fronts, the weather associated with a cold front usually
is more violent but of shorter duration
Relatively narrow, elongated bands of thunderstorms that develop in the warm sector of a middle-latitude cyclone, usually in advance of a cold front
Why do most tornadoes in the central U.S. occur during the spring months?
Air-mass contrasts are greatest
Why is very humid air near the surface a necessary ingredient for severe thunderstorms?
More latent heat energy available as storm
Tornadoes are most frequent during the
Late spring and early summer when warm and cold air often clashes
Why do surface wind speeds increase toward the center of a hurricane?
Conservation of angular momentum
Why do hurricanes in the Atlantic move toward the west during early stages?
Prevailing winds from the east
Problem with issuing a hurricane
80 to 90 percent living in these areas have not experienced a hurricane
The phenomenon that results from the speed of light changing as it passes into different substances
If light enters a transparent medium at a right angle, what change occurs
Slows down, and wavelength becomes shorter
The property of light that causes your arm to look bent when it is submerged in water is called
Thunderstorms are electrified by
Ice particles and supercooled water form above freezing level. Negative cloud charge
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