Continually cooled and descending air – subsidence, forms large high pressure areas. This happens at the poles, where the temperatures are coldest on earth’s surface. The descending air causes high pressures, called the polar highs. The south polar high is stronger than the north because it is over land.

At the equator, the altitude is lower and also because of the direct heating of sun rays on the surface, the temperature is much higher than at the poles. This makes the air near the surface hot and lighter and hence it rises up which results in lower air pressure.

Air pressure is caused by the weight of the air molecules above. This pressure causes air molecules at the Earth’s surface to be more tightly packed together than those that are high in the atmosphere.

At the poles, the cold dense air sinks. Air from the upper levels of the atmosphere flows in on top of it increasing the weight and creating an area of high pressure at the poles. Some of the air sinks, causing a belt of high-pressure at this latitude. The sinking air reaches the surface and flows north and south.

The cold air at the poles is denser than the warm air at the equator; hence, air pressure at sea level is higher at the poles than at the equator.

Air rises at the equator, leading to low pressure and rainfall. When the air reaches the edge of the atmosphere, it cannot go any further and so it travels to the north and south. The air becomes colder and denser, and falls, creating high pressure and dry conditions at around 30° north and south of the equator.

Equatorial regions is hotter and the air above expands, becomes less dense and rises. This produces a low pressure belt at this latitude.

If the reading falls between 29.80 and 30.20 inHg (100914.4–102268.9 Pa or 1022.689–1009.144 mb): Rising or steady pressure means present conditions will continue. Slowly falling pressure means little change in the weather. Rapidly falling pressure means that rain is likely, or snow if it is cold enough.

Low-pressure systems are associated with clouds and precipitation that minimize temperature changes throughout the day, whereas high-pressure systems normally associate with dry weather and mostly clear skies with larger diurnal temperature changes due to greater radiation at night and greater sunshine during the day.

If the high pressure originates from the north, it will generally bring cold or cooler weather. When high pressures form, they adopt the characteristics of the source regions over which they form. Cold, high-pressure air masses form in polar regions, and are called polar air masses.

Since stronger high-pressure systems contain cooler or drier air, the air mass is more dense and flows towards areas that are warm or moist, which are in the vicinity of low pressure areas in advance of their associated cold fronts.

A frigid air mass in Mongolia may have just crushed a world record for surface air pressure

• The pressure reading at Tsetsen-Uul tops the 1,089.4 millibars observed at Tosontsengel, also in Mongolia, on Dec.
• Pressure is a measurement of the weight of the air over a given area.

The highest sea-level pressure on Earth occurs in Siberia, where the Siberian High often attains a sea-level pressure above 1050 mbar (105 kPa; 31 inHg), with record highs close to 1085 mbar (108.5 kPa; 32.0 inHg).

Troposphere

High pressure occurs where a broad column of air in the atmosphere sinks toward the surface. As air descends, it warms and contracts, which reduces or prevents the formation of clouds. Because of this effect, areas of high pressure often create clear, dry weather.

Pressure and Pain Can it cause headaches and other discomforts? A. Differences in air pressure because of the weather or changes in altitude can have noticeable effects on the human body, though some people are more sensitive than others.

Barometric pressure often drops before bad weather. Lower air pressure pushes less against the body, allowing tissues to expand. Expanded tissues can put pressure on joints and cause pain. Dr.

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In addition to cold weather, blood pressure may also be affected by a sudden change in weather patterns, such as a weather front or a storm. Your body — and blood vessels — may react to abrupt changes in humidity, atmospheric pressure, cloud cover or wind in much the same way it reacts to cold.

Symptoms. Barometric pressure headaches occur after a drop in barometric pressure. They feel like your typical headache or migraine, but you may have some additional symptoms, including: nausea and vomiting.

Shifts in barometric pressure can also trigger pain and discomfort for those with sinusitis. This can result in sudden, painful feeling of pressure, sinus headaches, and facial pain, along with congestion. When such symptoms linger, the sinuses can become inflamed and blocked, which can lead to infection.

And the changing conditions can cause certain symptoms. Cold air can make your nose run and constrict airways. And if there’s a storm on the way, the atmospheric pressure changes can cause joint pain or even migraine headaches for some people. And after the rain, the rise in pollen can make your allergy symptoms worse.

One reason could be that the falling air pressure disrupts the vestibular system – the cavity in our heads that helps us to keep balance – bringing about the dizzy spells, and eventually, migraine.

Change in air pressure was significantly associated with onset of MD episodes, suggesting a potential triggering mechanism in the inner ear. MD patients may possibly use air pressure changes as an early warning system for vertigo attacks in the future.

The relationship between changes in barometric pressure and dizziness has been described in medical literature, particularly in patients suffering from migraine related vertigo and Ménière’s disease.