ESS 55 Final MC

When clouds are viewed near the horizon, the individual cloud elements usually

A. appear closer together than is actually the case.

Clouds are classified by their

A. appearance.

Radiation fog forms best on a

A. clear winter night with a slight breeze.

Dew is most likely to form on

A. clear, calm nights.

One would expect a cP air mass to be

A. cold and dry

Squall lines most often form ahead of a

A. cold front

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."

A. cold front

Which cloud type below would most likely form in an unstable atmosphere?

A. cumulonimbus

An anvil-shaped top is most often associated with

A. cumulonimbus.

Which association below is not correct?

A. cumulus congestus - anvil top

Vertical mixing of air tends to ____ a large environmental lapse rate.

A. decrease

On a clear night, the minimum temperature drops to 34F. 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

A. enhancement of the greenhouse effect by the fog cloud.

The rate at which the actual air temperature changes with increasing height above the surface is referred to as the

A. environmental lapse rate.

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?

A. freezing rain

When radiation fog "burns off", the fog tends to dissipate

A. from the bottom up.

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.

A. greater than

In a conditionally unstable atmosphere, the environmental lapse rate will be ____ than the moist adiabatic rate and ____ than the dry adiabatic rate.

A. greater, less

If you were to take a trip during the summer from Ohio to Nevada, you would most likely observe that afternoon cumulus clouds ____ as you travel west.

A. have higher cloud bases

If the air temperature remains constant, evaporating water into the air will ____ the dew point and ____ the relative humidity.

A. increase, increase

When the air temperature increases, the saturation vapor pressure will

A. increase.

Saturation vapor pressure ____ as temperature increases.

A. increases

Subsidence ____ stability.

A. increases

As the air temperature increases, the air's capacity for water vapor

A. increases.

Convective instability associated with severe thunderstorms and tornadoes can be brought on by

A. lifting a stable air layer whose surface is humid and whose top is dry.

Fronts are associated with

A. low pressure

What type of air mass would be responsible for persistent cold, damp weather with drizzle along the east coast of North America?

A. mP

During the spring, which air mass would most likely bring record-breaking high temperatures to the eastern half of the United States?

A. mT

The air mass with the highest actual water vapor content is

A. mT.

Which process below will change a moist layer of stable air into a deck of low stratocumulus clouds?

A. mixing

The largest snowflakes would probably be observed in ____ air whose temperature is ____ freezing.

A. moist, near

Suppose saturated polar air has an air temperature and dew point of -10°C, and unsaturated desert air has an air temperature of 35°C and a dew point of 10°C. The desert air contains ____ water vapor and has a ____ relative humidity than the polar air.

A. more, lower

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 ____ the surface water farther offshore.

A. much colder than

Light or moderate-but-steady precipitation is most often associated with ____ clouds.

A. nimbostratus

Satellites measure rainfall from space using which instrument?

A. radar

As the air temperature increases, with no addition of water vapor to the air, the dew point will

A. remain the same

At a warm front, the warm air

A. rises and cools

The most latent heat would be released in a ____ parcel of ____ saturated air.

A. rising, warm

The primary method used in preventing the growth of large, destructive hailstones is to inject a thunderstorm with large quantities of

A. silver iodide.

Which is NOT a correct association?

A. snow grains - hail

An mT air mass lying above a cold ground surface represents a(n) ____ situation.

A. stable

Air which resists vertical displacements is considered to be

A. stable.

If an air parcel is given a small push upward and it falls back to its original position, the atmosphere is said to be:

A. stable.

Which cloud would most likely produce drizzle?

A. stratus

Contact nucleation is

A. the freezing of supercooled droplets by contact with a nucleus.

In a blinding snowstorm in Vermont, the air temperature and dew-point temperature are both 30°F. Meanwhile, under clear skies in Arizona, the air temperature is 85°F and the dew point temperature is 38°F. From this information, you could conclude

A. there is more water vapor in the air in Arizona.

An upper-air front involves downward motion of the

A. tropopause.

Even at high elevations where cirrus clouds are found, liquid water still exists in the clouds.

A. true

Fog is a major hazard to aviation.

A. true

The dew point temperature is a measure of the total amount of water vapor in the air.

A. true

The relative humidity is often near 100 percent in the polar regions.

A. true

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 ____.

A. unsaturated, at or below freezing

At what time of day is the relative humidity normally at a minimum?

A. when the air temperature is highest

On average, the water equivalent of 10 inches of snow is about ____ inches of water.

B. 1

The total mass of water vapor stored in the atmosphere at any moment is about ____ of the world's supply of precipitation.

B. 1 week

Suppose it is snowing outside and the air is saturated. The air temperature and dew point are both 15°F, and the actual vapor pressure is 3 mb. If this air is brought indoors and warmed to 75°F, what would the relative humidity of this air be, assuming that its moisture content does not change? (The saturation vapor pressure at 75°F is 30 mb).

B. 10 percent

If a parcel of unsaturated air with a temperature of 30C rises from the surface to an altitude of 1,000 m, the unsaturated parcel temperature at this altitude would be about

B. 10C colder than at the surface.

If water vapor comprises 3.5 percent of an air parcel whose total pressure is 1000 mb, the water vapor pressure would be

B. 35 mb

At 40°F, the atmosphere is saturated with water vapor. If the air temperature increases to 60°F, with no addition or removal of water vapor, one may conclude that the dew point is about

B. 40°F.

Refer to Exhibit 4-1. Which city has the LEAST amount of water vapor in the air?

B. City B.

Refer to Exhibit 4-1. Which city has the highest relative humidity?

B. City B. 10F and 10F, lowest temperatures.

Which of the following statements is NOT correct?

B. Ice nuclei are more plentiful in the atmosphere than condensation nuclei.

Which of the following is not correct concerning a warm front?

B. It has warm air ahead (in advance) of it.

Which statement below best describes the curvature effect?

B. Small droplets evaporate more quickly than large droplets.

A completely dry air parcel which first rises and cools, and subsequently sinks and warms, is undergoing

B. a reversible adiabatic process.

Which cloud type below will only produce precipitation by the collision-coalescence process?

B. a thick, warm cumulus cloud

A halo around the sun or moon indicates that rain may be on the way because the halo indicates

B. a warm front may be approaching.

Which of the following will decrease in a rising parcel of air?

B. absolute humidity

If the environmental lapse rate is less than the moist adiabatic rate, the atmosphere is

B. absolutely stable.

Freshly fallen snow ____ sound waves.

B. absorbs

A rising parcel of air that does not exchange heat with its surroundings is an example of

B. an adiabatic process.

The difference in saturation vapor pressure between supercooled water and ice reaches a maximum at about -12C. This means that the ice crystal process will be most effective in producing precipitation when cloud temperatures are

B. around -12C.

Cumuliform cloud development would be most likely in which of the following?

B. cP air mass moving over warm water

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?

B. cP in winter

In winter, which sequence of clouds would you most likely expect to observe as a warm front with precipitation approaches your location?

B. cirrus, cirrostratus, altostratus, nimbostratus

An example of orographic clouds would be

B. clouds forming on the windward slope of a mountain.

As Apollo 12 ascended into the atmosphere, the height of the surrounding clouds was noted to be 42,000 feet. A lightning stroke was seen within these clouds, indicating that they must have been

B. cumulus congestus.

As the difference between the air temperature and the dew point increases, the relative humidity

B. decreases

The most common ice crystal shape is

B. dendrite.

Before the passage of a cold front the pressure normally ____, and after the passage of a cold front the pressure normally ____.

B. drops, rises

Fog that most often forms as warm rain falls into a cold layer of surface air is called

B. evaporation (mixing) fog.

A sling psychrometer directly measures the relative humidity.

B. false

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.

B. false

Sinking air sometimes cools adiabatically.

B. false

Suppose two unsaturated air masses mix horizontally. The resulting mixture cannot possibly be saturated.

B. false

The environmental lapse rate is almost always the same as the adiabatic lapse rate.

B. false

Large raindrops fall ____ than smaller raindrops, and have a ____ terminal velocity than small raindrops.

B. faster, greater

A good source region for an air mass would be

B. generally flat areas of uniform composition with light surface winds.

Which of the following might be mistaken for hail?

B. graupel

Subsidence inversions are best developed with ____ pressure areas because of the ____ air motions associated with them.

B. high, sinking

Suppose the dew point of cold outside air is the same as the dew point of the air indoors. If the door is opened and cold air replaces some of the warm air, then the new relative humidity indoors would be

B. higher than before

Evaporative coolers are primarily used in climates where the summers are

B. hot and dry.

During the ice crystal process of rain formation,

B. ice crystals grow larger at the expense of the surrounding liquid cloud droplets.

On a cold, winter morning, the most likely place for radiation fog to form is

B. in a valley.

In hilly areas, cold air typically collects

B. in valleys.

The instrument that measures humidity by measuring the amount of radiant energy absorbed by

B. infrared hygrometer.

A knowledge of air stability is important because

B. it determines the vertical motion of air.

Lake-effect snows are best developed around the Great Lakes during

B. late fall and early winter when cold, dry polar air moves over the relatively warm water.

The designation for a cool, moist air mass is

B. mP

What type of air mass would be responsible for daily afternoon thunderstorms along the Gulf Coast?

B. mT

What type of air mass would be responsible for hot, muggy summer weather in the eastern half of the United States?

B. mT

The ratio of the mass of water vapor in a given volume (parcel) of air to the mass of the remaining dry air describes the

B. mixing ratio.

The cooling of the ground to produce dew is mainly the result of

B. radiational cooling.

Which of the following will increase in a rising parcel of air?

B. relative humidity

The main difference between a cloud drop and a raindrop is its

B. size.

This instrument uses wet-bulb and dry-bulb temperature to obtain relative humidity:

B. sling psychrometer

Most thunderstorms do not extend very far into the stratosphere because the air in the stratosphere is

B. stable.

The dry adiabatic rate is the rate at which

B. temperature changes in a rising or descending parcel of unsaturated air.

Wintertime mP air masses are less common along the Atlantic coast of North America than along the Pacific coast mainly because

B. the prevailing winds aloft are westerly.

Large cloud droplets fall faster than small cloud droplets because

B. the ratio of the drop's surface area to its weight is smaller.

The main reason why vegetables take longer to cook in boiling water at high altitudes is because

B. the temperature of the boiling water decreases with increasing altitude.

A stationary front does not move because

B. the winds blow parallel to the front.

Frost typically forms on the inside of a windowpane (rather than the outside) because

B. there is more water vapor touching the inside of the pane.

Condensation nuclei are important in the atmosphere because

B. they make it easier for condensation to occur in the atmosphere.

If you observe large raindrops hitting the ground, you could probably say that the cloud overhead was ____ and had ____ updrafts.

B. thick, strong

In a sky filled with scattered cumulus humilis clouds, rising motions are found ____ the clouds and sinking motions are found ____ the clouds.

B. under, between

If an air parcel is given a small push upward and it continues to move upward on its own accord, the atmosphere is said to be

B. unstable.

____ are found beneath fair-weather cumulus (cumulus humilis) clouds, whereas ____ are found between the clouds.

B. updrafts, downdrafts

Rain which falls from a cloud but evaporates before reaching the ground is referred to as

B. virga.

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."

B. warm front

Compared to an mP air mass, mT air is

B. warmer and moister.

The temperature to which air must be cooled in order to become saturated is the

B. wet-bulb temperature

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?

C. 1 inch

What would the air temperature inside a conventional jet airliner be, if outside air at an altitude of 10 km, pressure of 250 mb and a temperature of -60C, is brought inside and compressed to a 1,000 mb pressure? (Hint: you may assume that 1,000 mb pressure is equivalent to 0 m altitude.)

C. 40C.

Suppose the surface air temperature is 66F. If the base of a cumulus congestus cloud directly above you is 2,000 feet, what would be the approximate temperature at an altitude of 5,000 feet above you inside the cloud? (Hint: the dry adiabatic rate is 5.5F per 1,000 feet, the moist adiabatic rate is 3.0F per 1,000 feet.)

C. 46F

When comparing an "average" cold front to an "average" warm front, which of the following is not correct?

C. Generally, precipitation covers a much broader area with a cold front.

With which set of conditions below would you expect wet laundry hanging outdoors on a clothesline to dry most quickly?

C. III. Air temp 60. RH 50%. Wind Speed 20.

Which of the following statements is most plausible?

C. In winter, cA source regions have lower temperatures than cP source regions.

Which of the following is not correct concerning a cold front?

C. It is colored purple on a weather map.

Which of the following statements is not correct?

C. The relative humidity is a measure of the air's actual water vapor content.

What two sets of conditions, working together, will make the atmosphere the most unstable?

C. Warm the surface and cool the air aloft.

A "back door" cold front describes which of the following situations?

C. a cold front that moves into New England from the Atlantic Ocean

The word "frontogenesis" on a weather map would mean that

C. a front is regenerating or strengthening

On a weather map, the transition zone between two air masses with sharply contrasting properties is marked by

C. a front.

Precipitation with the greatest size (diameter) is

C. a hailstone.

Alternating lines of blue and red on a surface weather chart indicate

C. a stationary front

Which below best describes the solute effect?

C. a. keeps water droplets from freezing at temperatures below 32F

The temperature at which water boils depends mainly on

C. air pressure

Which of the following set of surface conditions would produce a convective cumulus cloud with the highest base?

C. air temperature 35C, dew point 10C

Which of the following sets of conditions would produce a cumulus cloud with the lowest base?

C. air temperature 90F, dew point temperature 60F

Which of the following pairs of cloud types could be very similar in appearance?

C. altocumulus and cirrocumulus

Which association below is NOT correct?

C. altostratus - high cloud

The dry adiabatic lapse rate is ____ greater than the moist adiabatic lapse rate.

C. always

Radar gathers information about precipitation in clouds by measuring the

C. amount of energy reflected back to a transmitter.

Nighttime temperatures rarely drop below the dew point temperature because

C. at saturation, latent heat of condensation is released into the air.

The time of day when the relative humidity reaches a maximum value is usually

C. at the time when the air temperature is lowest.

Clear sunny days with very cold nights would be associated with what type of air mass?

C. cP

Record breaking low temperatures are associated with which air mass?

C. cP

What type of air mass would be responsible for refreshing cool, dry breezes after a long summer hot spell in the Central Plains?

C. cP

When viewed from the surface, the smallest individual cloud elements (puffs) are observed with which cloud?

C. cirrocumulus

Suppose the sky is completely covered with a thin, white layered-type cloud. You look at the ground and see that objects cast a distinct shadow. From this you conclude that the cloud type must be

C. cirrostratus.

Radiation fog typically forms on

C. clear, calm nights.

Cloud seeding using silver iodide only works in

C. cold clouds composed of ice crystals and supercooled droplets.

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."

C. cold-type occluded front

Particles that serve as surfaces on which water vapor may condense are called

C. condensation nuclei.

Upslope fog forms because air ____ as it flows up a hill or mountain range.

C. cools adiabatically

If rain falls on one side of a street and not on the other side, the rain most likely fell from a

C. cumulonimbus cloud.

The cloud with the greatest vertical growth is

C. cumulonimbus.

As the air temperature increases, with no addition of water vapor to the air, the relative humidity will

C. decrease

In a rising thermal, the dew-point temperature

C. decreases at a slower rate than the parcel temperature.

Which below is NOT a way in which a contrail may form?

C. due to heating of the air by the engine exhaust

Satellite images taken of clouds at night use

C. emitted infrared light.

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?

C. freezing rain

When temperatures are below freezing, the temperature to which air must be cooled in order for a phase change to occur is called the

C. frost point.

When the air temperature is below freezing, the saturation vapor pressure over water is

C. greater than the saturation vapor pressure over ice.

The Gulf Coast states are more humid in summer than the coastal areas of Southern California mainly because of the

C. higher water temperature in the Gulf of Mexico.

Cirrus clouds are composed primarily of

C. ice particles.

After a rainstorm, visibility typically

C. improves.

If very cold air is brought indoors and warmed with no change in its moisture content, the saturation vapor pressure of this air will ____ and the relative humidity of this air will ____.

C. increase, decrease

Supercooled cloud droplets are

C. liquid droplets observed at temperatures below 0C (32F).

Which cloud forms in descending air?

C. mammatus

The rate at which the temperature changes inside a rising (or descending) parcel of saturated air is called the

C. moist adiabatic lapse rate.

The temperature an air parcel would have if it were moved to a pressure of 1,000 mb at the dry adiabatic rate is called the

C. potential temperature.

Condensation onto hygroscopic nuclei is possible at relative humidities less than 100 percent due to the

C. solute effect.

A conditionally unstable atmosphere is ____ with respect to unsaturated air and ____ with respect to saturated air.

C. stable, unstable

If the air temperature increased, with no addition or removal of water vapor, the actual vapor pressure would

C. stay the same.

Which of the following associations is not correct?

C. stratocumulus - cloud of vertical development

Fall streaks usually ____ before reaching the ground.

C. sublimate

If a glass of water was surrounded by saturated air,

C. the level of the water in the glass would not change.

Which of the following is NOT an important factor in the production of rain by the collision-coalescence process?

C. the number of ice crystals in the cloud

Soaring birds in flight, like hawks and eagles, often indicate the presence of

C. thermals

If fog is forming at Denver, Colorado, and the wind is blowing from the east, then the fog is most likely

C. upslope fog.

Homogeneous nucleation occurs when

C. water vapor condenses without nuclei.

Ignoring the contributions of wind, a baseball would be expected to travel farther in warm, humid air because

C. water vapor is less dense than dry air.

The lowest temperature that can be attained by evaporating water into the air is known as the

C. wet-bulb temperature.

Along the boundary between continental polar and maritime tropical air masses, ____ is often found.

C. widespread precipitation and storminess

The temperature at which you would expect a cloud to become completely glaciated is

D. -40C (-40F).

Which of the following environmental lapse rates would represent the most unstable atmosphere in a layer of unsaturated air?

D. 11C per 1,000 m

If the environmental lapse rate is 5C per 1,000 m and the temperature at the earth's surface is 25C, then the air temperature at 2,000 m above the ground is

D. 15C.

If the air temperature in a room is 70°F, the saturation vapor pressure is 25 mb, the dew point temperature is 45°F, and the actual vapor pressure is 10 mb, then the relative humidity must be near ____ percent.

D. 40

When the air is saturated, which of the following statements is NOT correct?

D. An increase in temperature will cause condensation to occur.

Which below is not correct concerning an occluded front?

D. At the surface, it is always followed by colder air.

The origin of cP and cA air masses that enter the United States is

D. Northern Canada and Alaska.

The lake effect occurs when ____ air mass moves over a ____ body of water.

D. a cP, warm

The fog that forms along the Pacific coastline of North America is mainly which type?

D. advection fog

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

D. advection fog.

Exhaled breath from your mouth can condense when

D. all of the above

Ice nuclei may be

D. all of the above

Infrared satellite images are computer enhanced to

D. all of the above

Which condition below could make a layer of air more unstable?

D. all of the above

Frost forms when

D. all of the above. objects on the ground cool below the dew point temperature. the dew point is 32F or below. water vapor changes into ice without first becoming a liquid.

Which of the following statements is (are) correct?

D. all of the above....Convection can occur over the ocean. Air motions are usually downward around a cumulus cloud. The temperature of the rising air at a given level inside a cumulus cloud is normally warmer that the air around the cloud.

Hail is usually associated with what cloud?

D. altocumulus

A dim, "watery" sun visible through a gray sheet-like cloud layer is often a good indication of ____ clouds.

D. altostratus

Which of the following conditions would be described as the most stable?

D. an inversion

Continental polar (cP) and continental Arctic (cA) air masses

D. are very similar.

Which cloud is least likely to produce precipitation that reaches the ground?

D. cirrocumulus

Which cloud type is composed of ice crystals and can cause a halo to form around the sun or moon?

D. cirrostratus

Detached clouds of delicate and fibrous appearance, without shading, usually white in color and sometimes of a silky appearance are

D. cirrus.

An example of orographic clouds would be

D. clouds that form on the upwind slope of a mountain.

An inversion represents an extremely stable atmosphere because air that rises into the inversion will eventually become ____ and ____ dense than the surrounding air.

D. colder, more

Which two clouds can produce precipitation?

D. cumulonimbus, nimbostratus

Which of the following is the BEST indicator of the actual amount of water vapor in the air?

D. dew point temperature

The lightest form of rain is

D. drizzle.

A true cold front on a weather map is always

D. followed by cooler air.

The greatest contrast in both temperature and moisture will occur along the boundary separating which air masses?

D. mT and cP

Large, heavy snowflakes are associated with

D. moist air and temperatures near freezing.

The maximum pressure that water vapor molecules would exert if the air were saturated is called the

D. none of the above

A typical raindrop is about ____ than a typical cloud droplet.

D. one hundred times larger

In a typical advancing winter storm, which of the following sequences of precipitation types is most likely to occur?

D. rain, freezing rain, sleet, snow

The percentage of water vapor present in the air compared to that required for saturation is the

D. relative humidity.

Conditional instability depends on the condition of

D. saturation.

During the winter as you travel toward a warm front, the most likely sequence of weather you would experience is

D. snow, sleet, freezing rain, rain.

A low, lumpy cloud layer that appears in rows, patches, or rounded masses would be classified

D. stratocumulus.

Which of the following will increase the relative humidity in a home during the winter?

D. taking a shower and letting the air circulate through the home

An air mass is characterized by similar properties of ____ and ____ in any horizontal direction.

D. temperature, moisture

The difference between the "moist" and "dry" adiabatic rates is due to

D. the fact that latent heat is released by a rising parcel of saturated air.

If the amount of water vapor in the atmosphere remains constant, the humidity

D. will only change if we're using absolute humidity as the measure of humidity.

After a snowstorm, the newspaper reports that Buffalo, New York, received 1.50 inches of precipitation. If we assume an average water equivalent ratio for this snowstorm, then Buffalo received about ____ inches of snow.

E. 15

If a pilot balloon rises at a rate of 100 m per minute, and if it disappears into a deck of stratus clouds 1,500 m (5,000 ft) thick in 5 minutes, what is the ceiling of the cloud layer?

E. 2,000 m (6,400 ft)

Satellites can

E. all of the above

A true blizzard is characterized by

E. all of these.

A dryline is

E. both a dew point front and a boundary marking a strong horizontal change in atmospheric moisture.

Which of the following would increase the environmental lapse rate?

E. both cold advection at higher altitudes and daytime solar heating

The coldest of all air masses is

E. cA.

Fall streaks most often form with

E. cirrus clouds.

The only indication on the station model of past weather conditions is the

E. pressure tendency

What are the two main substances used in cloud seeding?

E. silver iodide, dry ice

Condensation nuclei may be

e. all of the above.

At the earth's surface, a rising saturated air parcel would cool most rapidly when its temperature is

A. 10F.

Refer to Exhibit 4-1. Which city has the HIGHEST saturation vapor pressure?

A. City A.

Refer to Exhibit 4-1. Which city has the GREATEST amount of water vapor in the air?

A. City A. Highest temperature and dew point.

Which set of conditions, working together, will make the atmosphere the most stable?

A. Cool the surface and warm the air aloft.

Which below best describes why a fluffy covering of snow is able to protect sensitive plants and their root systems from damaging low temperatures?

A. Snow is a good insulator.

Which condition below is necessary for a layer of altostratus clouds to change into altocumulus?

A. The top part of the cloud deck cools while the bottom part warms.

Occluded fronts may form as

A. a cold front overtakes a warm front.

A high water vapor pressure indicates

A. a relatively large number of water vapor molecules in the air.

Just above cumulus clouds you would expect to find

A. a stable layer.

An amount of precipitation measured to be less than one hundredth of an inch (0.25 mm) is called

A. a trace

The density of water vapor in a given parcel of air is expressed by the

A. absolute humidity

The growth of a precipitation particle by the collision of an ice crystal (or snowflake) with a supercooled liquid droplet is called

A. accretion.