Weather Maps

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Weather Map Noun

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[weth-er map]

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Weather Map

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A map that indicates various weather conditions for a specific area, showing either current or predicted weather.

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Example: This weather map shows high (H) and low (L) pressure systems, cold and warm fronts, and isobars (lines of equal air pressure).

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Air Mass Noun

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[air mas]

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Air Mass

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A large body of air that has uniform properties of temperature and moisture throughout its entire volume.

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Example: This weather map diagram shows two different air masses: a cold air mass (blue temperatures) is moving in to replace a warm air mass (red temperatures).

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Air Pressure Noun

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[air presh-er]

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Air Pressure

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The force exerted by the weight of the atmosphere, which causes air to move from high to low-pressure areas.

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Example: This diagram shows air pressure is the weight of air. At high altitudes, there's less air above, causing lower pressure, while at low altitudes, there's more air, causing higher pressure.

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Millibar Noun

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[mil-i-bar]

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Millibar

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The standard unit of measurement for atmospheric pressure that is commonly used on weather maps to denote pressure levels.

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Example: This weather map shows isobars, lines connecting areas of equal air pressure. The numbers on the lines, like 1020, represent the pressure in millibars.

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Isobars Noun

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[eye-so-barz]

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Isobars

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Lines on a weather map that connect places having the same atmospheric pressure at a given time.

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Example: This weather map shows isobars, which are lines connecting points of equal air pressure, creating high-pressure (H) and low-pressure (L) areas.

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High-Pressure System Noun

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[hy-presh-er sis-tem]

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High-Pressure System

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A weather system with sinking air that moves clockwise, usually resulting in clear, fair weather and dry conditions.

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Example: This diagram shows a high-pressure system where cool, dense air sinks towards the ground and then spreads outwards, creating clear, calm weather.

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Low-Pressure System Noun

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[loh-presh-er sis-tem]

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Low-Pressure System

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A weather system with rising air that moves counterclockwise, often bringing cloudy skies, moisture, and potential storms.

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Example: In a low-pressure system, warmer, less dense air rises from the surface. As the air rises and cools, water vapor condenses, forming clouds and precipitation.

Front

Front Noun

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[frunt]

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Front

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A boundary where two different air masses meet, which is often a site of significant weather changes.

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Example: This diagram shows a warm front on a weather map, where a warm air mass (higher temperatures) is advancing and rising over a cooler air mass.

Front

Cold Front Noun

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[kohld frunt]

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Cold Front

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A boundary formed when a cold air mass pushes under a warm air mass, typically bringing fast-moving, strong storms.

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Example: This diagram shows how a moving mass of dense, cold air wedges under warmer air, forcing it to rise rapidly, cool, and form storm clouds.

Front

Warm Front Noun

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[worm frunt]

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Warm Front

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A boundary formed when a warm air mass slides over a cold air mass, typically bringing steady, widespread precipitation.

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Example: This diagram shows how a warm front forms when a moving mass of warm air slides up and over a colder air mass, causing clouds and steady rain.