VERY IMPORTANT: 8th Grade Science: Air Masses

What symbolizes a cold front on a weather map?

A cold front is symbolized by a blue line with triangles attached to it that determine its direction of movement.

What is a front? How does a front appear on a weather map?

A front is the boundary between two air masses, and appears on the weather map as a colored line with triangles or half circles attached.

What symbolizes a stationary front on a weather map?

A stationary front is symbolized with a line that alternates blue and red, and has both triangles and half circles attached to it that determine its direction of movement.

What is an Air Mass?

A volume of air defined by its temperature and water vapor content.

What symbolizes a warm front on a weather map?

A warm front is symbolized by a red line with half circles attached to it that determine its direction of movement.

Where do Air Masses Form?

Air masses form over regions where the air is stable for a long enough time that the air can take on the characteristics of the region.

Air Mass Movement

Air masses move when they are pushed by high level winds.

How large can an air mass be?

An air mass can cover hundreds or thousands of square miles, and adopt the characteristics of the surface below them.

What is the General Tempature of an Air Mass?

An air mass has roughly the same temperature and humidity.

Define isobar, isotach, and isotherm.

An isobar is a line of constant pressure, isotachs are lines of constant wind speed, and isotherms are lines of constant temperature.

What symbolizes an occluded front on a weather map?

An occluded front is symbolized with a purple line that has both triangles and half circles attached to it that determine its direction of movement.

Describe the cloud sequence that goes along with a warm front.

Cirrus clouds become thicker which then causes cirrostratus clouds to form. Slowly, when the front becomes closer, altocumulus and altostratus clouds appear, therefore turning the sky gray. If it is winter time, snowflakes will begin to fall. Next, the clouds become dense and nimbostratus clouds form. Immediately, the snowfall increases. As the front gets closer, the winds grow stronger as the low pressure approaches. Temperatures will rise as the snow turns to sleet and freezing cold rain. When warm and cold air mix at the front, stratus clouds and fog will form.

How do the Movements of air Masses Moderate Temperature?

Cold air masses go towards the Equator and warm air masses go towards the poles. This brings warmth to the cold areas and frost to the warm ones. This process is how the earth moderates its temperature.

Where do continental air masses form and what are their characteristics?

Continental air masses form on land. Their characteristics consist of being dry. They can also be hot or cold depending on whether or not they are close to the equator.

How does Coriolis effect create an occluded front?

Coriolis effect creates and curves the meeting point of two fronts towards the poles. The temperature of the third air mass to arrive will determine whether or not a warm or cold occlusion will occur.

What characteristics give warm fronts and cold fronts their names?

Different temperatures give fronts their names. Density can also determine whether or not you are dealing with a warm or cold front.

Why do air Masses Form Mostly in High Pressure Areas?

High pressure areas make it stable for air masses to form. Source air contains uniform temperature and humidity.

How are high and low pressure cells indicated on a weather map?

High pressure is identifiable on a weather map with enclosed pressure bars which increases in pressure towards the center. Low pressure is identifiable on a weather map with spaced out pressure bars which decreases in pressure towards the center.

If the H weren't on a weather map, how could you still tell there was a high pressure? How could you identify a low pressure?

High pressure is identifiable on a weather map with enclosed pressure bars which increases in pressure towards the center. Low pressure is identifiable on a weather map with spaced out pressure bars which decreases in pressure towards the center.

How are high pressure areas identified on a weather map? What does that look like in real life?

High pressure systems are recognized with a capitalized blue H, and are identified with clear skies and little wind.

How does wind blow relative to high and low pressure cells?

In the Southern hemisphere, wind flows from high pressure to low pressure clockwise around low pressure systems, and from low pressure to high pressure counter clockwise around high pressure systems. In the Northern hemisphere, wind flows counter clockwise around low pressure systems, and clockwise around high pressure systems.

What is the purpose of Isobars?

Isobars indicate pressure cells.

What do isobars join?

Isobars join points of equal air pressure. Isobars are lines of constant pressure.

What is an isoline map?

Isoline maps are made up of lines that join points of equal value.

Where do maritime air masses form and what are their characteristics?

Maritime air masses form closer to water. Their characteristics consist of being humid. Like continental air masses, these air masses can be hot or cold depending on wether or not they are close to the equator.

What is the difference in air pressure between isolines on an American weather map?

On an American weather map, Isobars are drawn in intervals of four millibars.

Where do polar air masses form and what are their characteristics?

Polar air masses form in the arctic, which makes them farther away from the equator. Polar air masses are cold and frigid.

What is the Relationship Between air Masses and Storms?

Storms form along the boundaries of air masses. When two different types of air masses collide, they can form a storm.

How are low pressure areas identified on a weather map? What does that look like in real life?

The capitalized red letter L stands for low pressure systems, and can be identified in real life with rain, clouds, and high winds.

What are the four air mass types and what are their major characteristics?

The four air mass types are: Tropical, Polar, Maritime, and Continental. The Tropical air masses are hot, the Polar are cold and frigid, the Maritime are humid, and the Continental are dry.

What is the purpose of isolines on a weather map?

The purpose of isolines on a weather map is to join points of equal value.

Where do tropical air masses form and what are their characteristics?

Tropical air masses form closer to the equator, in hotter areas. They are basically the opposite of polar air masses. Their characteristics consist of being very hot.

What is the purpose of a weather map?

Weather maps graphically depict weather conditions.

What does it mean when the isolines are close together?

When isolines are close together, winds are strong, whereas when isolines are far apart, the wind is weak.