Isobars

Isobars are lines on a map that connect points with the same barometric pressure. The pressure is measured by a barometer and is usually reported in millibars (mb) or inches of mercury. Millibars are the international unit of measure for atmospheric pressure, while inches of mercury is used in the United States.

What are isobars?

Isobars are lines on a map that join places with the same or similar air pressure. Closely spaced isobars indicate strong winds.

How are isobars created?

Isobars are created when the pressure at one location is equal to the pressure at another location. The pressure is usually caused by the weight of the air above the surface. Isobars can also be created by other factors such as temperature, humidity, and altitude.

When isobars are close together, it indicates that the pressure gradient is large and that the pressure is changing rapidly. This can be due to either a rapid increase in pressure (such as with a low-pressure system) or a rapid decrease in pressure (such as with a high-pressure system). Either way, close-spaced isobars indicate that the weather is likely to change quickly.

What do closely spaced isobars indicate?

iOS bars (isobar charts) show the relationship between two variables, typically price and time. Isobars are drawn on. Can be used to spot support and resistance levels, trendlines, and price patterns.

The Effect of Isobars on Weather

Isobars are lines on a map that connect points with the same barometric pressure. The closer the isobars are together, the greater the difference in pressure, and the greater the wind speed. This can have a significant effect on the weather.

How do isobars affect weather patterns?

Isobars are lines drawn on weather maps to join points with equal or similar atmospheric pressure. The closer the isobars are together, the greater the difference in pressure, and usually, but not always, the stronger the wind. Low-pressure areas are associated with warm air rising and generally wet weather, while high-pressure areas are associated with sinking air and generally dry weather.

What is the difference between high and low pressure systems?

The placement of the isobars on a weather map indicates the direction of the wind flow. If the isobars are close together, then the wind is blowing very hard. If the isobars are far apart, then the wind is blowing very slowly.

What are the consequences of a high or low pressure system?

A high pressure system is an area of stable air creating a dome-like shape. It rotates in a clockwise direction in the Northern Hemisphere. A low pressure system is less dense, creating an area of unstable air which rotates counterclockwise in the Northern Hemisphere. The terms “high” and “low” refer to the air pressure within the system. High pressure systems have higher than normal atmospheric pressure, while low pressure systems have lower than normal atmospheric pressure.