What is a trough axis?

Asked by: Angela Wallace

When the height contours bend strongly to the south, (as in the diagram below), it is called a TROUGH. Strong troughs are typically preceded by stormy weather and colder air at the surface. Below is an example of a trough in an upper-level height field (red contours). The trough axis is denoted by the purple line.

What does a trough line indicate?

Troughs are elongated regions where there is low pressure, and they typically occur before a cold front. A trough is often an indicator of coming clouds, showers, or a shift in the direction of the wind. Ridges, in weather terminology, are elongated regions of relatively high pressure.

How do you find the trough of an axis?

You look at the point where the axis intersects an isobar. And you know the value of pressure right on the isobar.

What is a trough on a map?

Broadly speaking, troughs and ridges are properties of the pressure field and they can easily be seen on a weather map. Troughs are found near low pressure areas while ridges are found near high pressure. Below is an example of what they tend to look like.

What weather does a trough bring?

A trough can bring in cloudy conditions and precipitation or they can bring in a cold air mass. A ridge is a region with relatively higher heights. A broad region of sinking air or a deep warm air mass will both lead to ridging. Since air is often sinking within a ridge they tend to bring warmer and drier weather.

What causes a blocking high?

Blocking High



Any precipitation is usually shunted around the periphery of the high-pressure area. High pressure aloft causes the air to subside or sink. This downward motion compresses and warms the air in the lower atmosphere while simultaneously trapping heat rising from the earth’s surface, leading to heat waves.

What does a trough look like?

In the United States, a trough may be marked as a dashed line or bold line. In the UK, Hong Kong and Fiji, it is represented by a bold line extended from a low pressure center or between two low pressure centers; in Macau and Australia, it is a dashed line.

What is a trough in physics?

The trough of a wave is the point on the medium that exhibits the maximum amount of negative or downward displacement from the rest position.

What is trough and ridge?

Ridges and troughs are often mentioned on the weather forecast. A ridge is an elongated area of relatively high pressure extending from the center of a high-pressure region. A trough is an elongated area of relatively low pressure extending from the center of a region of low pressure.

What is a trough in chemistry?

noun. chemistry. a shallow dishlike vessel filled with a liquid, usually water, and used in collecting gases by displacement of liquid from a filled jar held with its open end under the surface of the liquid.

What happens in a trough?

Key Takeaways



A trough, in economic terms, can refer to a stage in the business cycle where activity is bottoming, or where prices are bottoming, before a rise. The business cycle is the upward and downward movement of gross domestic product (GDP) and consists of recessions and expansions that end in peaks and troughs.

Why do troughs cause rain?

Like cold fronts, troughs separate two different air masses (usually more moist air on one side and drier air on the other). As the trough moves towards the moist air it lifts it. This causes cloud or even showers and thunderstorms to develop.

How does a trough differ from a front?

A front pushes air upward, and if there is a trough overhead, the air goes up into the trough.

What is a trough on a surface analysis chart?

Trough. An elongated area of relatively low atmospheric pressure; the opposite of a ridge. On HPC’s surface analyses, this feature is also used to depict outflow boundaries.