Introductory Meteorology (Aldrich) - Unit 3

Horizontal pressure variations cause air to move from areas of _____ pressure to areas of ____ pressure.​

high; low

Atmospheric air pressure always ______ with height.

Decreases

The contour lines drawn on a 500 mb chart are lines of constant​ ____.

Pressure

A rapid change in pressure over a relatively short distance is called a ____ pressure gradient.​

Steep

​Which of the following is MOST likely associated with fair weather?

High pressure area

These forces are the ____________________ force, the ____________________ force, and the Coriolis force.

Frictional; Pressure Gradient

Which instrument measures pressure?​

Barometer

The unit of pressure most commonly found on a surface weather map is​

millibars or hectopascals

Zonal flow wind-flow patterns are associated with​

West-to-east flows

We can generally expect the air to be _____ above areas of surface low pressure and ______ above areas of surface high pressure.

Rising; sinking

The magnitude of the Coriolis force varies with ____ and ____.​

Speed; latitude

To correctly monitor horizontal changes in air pressure, the most important correction for a mercury barometer is the correction for​

Altitude

​The pressure gradient force is non-existent at the equator.

True

Upper-level winds in the middle latitudes of both hemispheres generally blow from ____.​

The west

The most common type of home barometer is called the aneroid barometer.

Aneroid

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​

Increase

We can generally expect the air to be _______ above areas of surface low pressure and_____ above areas of surface high pressure.

Rising; Sinking

Atmospheric air pressure always decreases with height.

Decreases

​A pilot enters the weather service office and wants to know what time of the day she can expect to encounter the least turbulent winds at 760 m (2500 ft) above central Kansas. If you were the weather forecaster, what would you tell her?

In the early morning

​Wind blowing with sufficient force to rip the roof off buildings

Is uncommon

​Which of the following conditions favor the development of dust devils?

Hot, dry

True or False: Coastal areas can have strong waves on a clear, non-stormy day.

True

​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

True or False: The difference in surface wind speed between morning and afternoon is typically greater on a clear, sunny day than on a cloudy, overcast day.

True

​Chinook winds are

warm, dry winds that blow downslope in mountainous areas.

An example of microscale motion is:

winds blowing through Jerseyville, Illinois.

A wind reported as 45° would be a wind blowing from the:

NE

True or False: Storms rank in size from largest to smallest, as follows: middle-latitude cyclonic storm, hurricane, thunderstorm, tornado.

True

True or False: Coastal areas can have strong waves on a clear, non-stormy day.

True

True or False: Chinook winds are a common phenomenon on the east side of the Appalachians.

False

​Wind blowing with sufficient force to rip the roof off buildings

Is uncommon

​The wind's speed generally increases with height above Earth's surface because

​friction with Earth's surface slows the air near the ground.

True or False: Wind direction and speed can be determined with an aerovane.

True

​If you are standing directly south of a smoke stack and the wind from the stack is blowing over your head, what would be the wind direction

North

​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.

​A wind reported as 45° would be a wind blowing from the

NE

True or False: A valley breeze develops its maximum strength in the early afternoon.

True

True or False: At any given time, only one jet stream can be found in the atmosphere.

False

When we examine the real world, we obtain an average distribution of sea-level pressure and winds for January and July, and we can observe that there are regions where pressure systems appear to persist throughout the year. These systems are referred to as ____________________ because they

move only slightly during the course of a year.​ Semipermanent lows and highs

True or False: Weather in the middle latitudes tends to move from east to west.​

False

The position of the Pacific high over the north Pacific Ocean shifts _______ in winter and _________ in summer.

Southward, northward

Most of the United States is located within the prevailing trade winds wind belt.​​

Westerlies

During a major El Niño event,​

extensive ocean warming occurs over the tropical Pacific.

The name given to the current of warm water that replaces cold surface water along the coast of Peru and Ecuador during December is​

El Nino

Which statement describes the polar front jet stream?​

It forms near the boundary called the polar front.

____________________ momentum is defined as the product of the mass (m) times the velocity (v)times the radial distance (r).​

Angular

A condition where the central and eastern tropical Pacific Ocean turns cooler than normal is called​

La Nina

Why is the polar jetstream strongest in the winter and weakest in the summer (in the northern hemisphere)?

The general circulation of the atmosphere shifts south toward the equator, drawing in colder air from the arctic into the United States.

The large thermally driven convection cell that is driven by convective "hot" towers along the equator is the​

Hadley cell

According to the three-cell general circulation model, at the equator we would not expect to find​

a ridge of high pressure

In terms of the three-cell model of the general circulation, areas of surface low pressure should be found at​

30° latitude and 60° latitude.

Jet streams can form near Earth's surface as well. One such jet develops just above the central plains of the United States, where it occasionally attains speeds exceeding 60 knots. This wind speed maximum, which usually flows from the south or southwest, is known as a(n) ____________________ jet.​

Low-level

The jet stream flows​

In a wavy pattern from west to east

​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?

Thermal low

One would expect a cP air mass to be

Cold and dry

​On a weather map, sharp changes in temperature, humidity, and wind direction are marked by a

Front

A true cold front on a weather map is always followed by

Colder air

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

Pressure tendency

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

mT

What type of weather front would likely 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."

Warm front

Along a dryline, the ____ may drop markedly.

Dew point temperature

True or False: Fronts are associated with high pressure​.

False

As the temperature contrast across a front lessens, the front will often weaken and dissipate. Such a condition is known as ____________________.

Frontolysis

During the spring, on a warm, sunny day in Boston, Massachusetts, the wind shifts from southwesterly to northeasterly and the weather turns cold, damp, and overcast. This suggests that a "back door" cold front approached Boston from the

NE

​On weather maps cold fronts are drawn

in blue, with arrowheads showing the front's general direction of movement.

Barometric pressure usually falls with the approach of a(n) cold front or occluded front.​

Cold; occluded

A(n) ___________________ front has essentially no movement.​

Stationary

"Back door" cold front best describes which of the following situations?

a cold front moving into Washington state from the Pacific ocean

A good source region for an air mass would be

generally flat areas of uniform composition with light surface winds.

Squall lines most often form ahead of a

Cold front

The weather forecast "Increasing cloudiness and warm today, with the possibility of showers by evening. Turning much colder tonight. Winds southwesterly, becoming gusty and shifting to northwesterly by tonight." suggests that a(n) ___________________ front is going to pass the area.​

Cold

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

A front

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

mP