Pressure Systems:
There are two kinds of pressure systems. The first one is a high pressure system, which is the result of shifting winds. This type of system means the pressure inside the system is higher than that of the surrounding areas. High pressure areas are usually caused by air masses being cooled, either from below or from above. As the air mass cools, it shrinks, which causes the air from the surroundings to fill in above
it, which then results in higher surface pressures. Because of the rotation of the Earth, the wind is deflected to the right (in the Northern Hemisphere) which the causes the wind to flow in a clockwise direction around the high pressure zone. If a high pressure zone moves in from the south, the weather is usually warm and clear in the summer. However, a high pressure zone originating from the north will usually bring cold weather in the winter months.
The second type of pressure system is called a low pressure system, which happens when air rises, it cools and often condenses into clouds and rain. Usually, cloudy weather and precipitation often result as the low-pressure area approaches. A steady rain or snow can fall to the north of the warm front as warm moist air from the south rises up and over the cold air ahead of the warm front. Showers and thunderstorms often begin ahead of the cold front in the warm air. Showers and thunderstorms ahead of the cold front are much shorter in duration than the precipitation ahead of the warm front. Because the counterclockwise circulation around low-pressure areas in the northern hemisphere, cold air will likely be found to the north and west of low-pressure areas while warm air is most often found to the south and east of low-pressure areas.
There are two kinds of pressure systems. The first one is a high pressure system, which is the result of shifting winds. This type of system means the pressure inside the system is higher than that of the surrounding areas. High pressure areas are usually caused by air masses being cooled, either from below or from above. As the air mass cools, it shrinks, which causes the air from the surroundings to fill in above
it, which then results in higher surface pressures. Because of the rotation of the Earth, the wind is deflected to the right (in the Northern Hemisphere) which the causes the wind to flow in a clockwise direction around the high pressure zone. If a high pressure zone moves in from the south, the weather is usually warm and clear in the summer. However, a high pressure zone originating from the north will usually bring cold weather in the winter months.
The second type of pressure system is called a low pressure system, which happens when air rises, it cools and often condenses into clouds and rain. Usually, cloudy weather and precipitation often result as the low-pressure area approaches. A steady rain or snow can fall to the north of the warm front as warm moist air from the south rises up and over the cold air ahead of the warm front. Showers and thunderstorms often begin ahead of the cold front in the warm air. Showers and thunderstorms ahead of the cold front are much shorter in duration than the precipitation ahead of the warm front. Because the counterclockwise circulation around low-pressure areas in the northern hemisphere, cold air will likely be found to the north and west of low-pressure areas while warm air is most often found to the south and east of low-pressure areas.