Air Masses and Weather Fronts

Front

Air Mass Noun

---

[air mas]

Back

Air Mass

---

A huge body of air that has similar temperature, humidity, and air pressure throughout its horizontal extent.

---

Example: This map shows different types of air masses. Blue polar masses are cold, and red tropical masses are warm. They form over land (continental) or water (maritime).

Front

Front Noun

---

[frunt]

Back

Front

---

The boundary where two different air masses meet, which often results in significant changes in weather conditions.

---

Example: This diagram shows a cold front, where a dense cold air mass plows under a lighter warm air mass, forcing it to rise, cool, and form clouds and rain.

Front

Continental Adjective

---

[kon-tuh-nen-tl]

Back

Continental

---

An adjective describing a dry air mass that forms over a large land area and carries very little moisture.

---

Example: This diagram shows a large air mass forming over land (a continent), which is the defining characteristic of a continental air mass.

Front

Maritime Adjective

---

[mair-i-tahym]

Back

Maritime

---

An adjective describing a moist air mass that forms over a large body of water, carrying significant moisture content.

---

Example: This diagram shows that the air over a large body of water is cooler and contains more moisture (clouds, fog) than the air over land.

Front

Tropical Adjective

---

[trop-i-kuhl]

Back

Tropical

---

An adjective describing a warm air mass that originates in low-latitude regions near the equator, bringing warm temperatures.

---

Example: This map shows the Tropics, the warm region around the Earth's equator where tropical air masses form before moving to other areas.

Front

Polar Adjective

---

[poh-ler]

Back

Polar

---

An adjective describing a cold air mass that forms in high-latitude regions near the poles, bringing cool air.

---

Example: This diagram shows a maritime Polar (mP) air mass moving from the ocean over mountains, cooling and releasing rain, then becoming dry on the other side.

Front

Source Region Noun

---

[sors ree-juhn]

Back

Source Region

---

The geographic area where an air mass develops and acquires its distinct properties of temperature and humidity from the surface.

---

Example: This image shows the different source regions of air masses, helping students understand where different air types originate.

Front

Cold Front Noun

---

[kohld frunt]

Back

Cold Front

---

A boundary where a fast-moving cold air mass pushes a warmer air mass upward, often causing abrupt, intense weather.

---

Example: This diagram shows a dense mass of cold air advancing and wedging under a lighter warm air mass, forcing it to rise rapidly.

Front

Warm Front Noun

---

[wawrm frunt]

Back

Warm Front

---

A boundary where a warm air mass gently slides up and over a colder air mass, producing steady, light precipitation.

---

Example: This diagram shows the map symbol for a warm front, where a warmer air mass is advancing and replacing a colder air mass.

Front

Stationary Front Noun

---

[stey-shuh-ner-ee frunt]

Back

Stationary Front

---

A boundary where warm and cold air masses meet but neither can advance, causing prolonged cloudy and wet weather.

---

Example: This diagram shows a stationary front, where a cold air mass and a warm air mass meet but neither has enough force to move the other.