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All Weather Starts with the Sun
All Weather Starts with the Sun
Energy in the form of radiation reaches our planet and heats it up.
Differences in heating results in convection currents. Wind and weather are caused by these convection currents.
Convection
Convection
In this diagram to the left, you can see that Radiation from the sun heats the planet. The air above the hot land heats up.
Its density decreases and the air rises.
After this air loses its heat to space, it becomes denser and sinks. Cool air comes in to take the place of the rising air. This is a convection current.
This diagram explains how we get wind and weather.
What is a High-Pressure System?
What is a High-Pressure System?
Imagine looking down from space at various weather systems. A high-pressure system is a whirling mass of cool, dry air that generally brings nice, clear weather and light winds.
As compared to low-pressure systems, high-pressure systems have a lot of air molecules per cubic centimeter – they have a relatively high density. This dense air falls and pushes down on a barometer resulting in a “high -pressure” reading.
When viewed from above, winds spiral out of a high-pressure center in a clockwise rotation in the Northern Hemisphere. A high-pressure system is represented as a big, blue H.
What is a Low-Pressure System?
What is a Low-Pressure System?
You are still looking down at various weather systems. A low-pressure system is a whirling mass of warm, wet air that generally brings stormy weather with strong winds.
Low-pressure systems have relatively few air molecules per cubic centimeter – they have a relatively low density. The less-dense air rises upward away from a barometer resulting in a “low-pressure” reading.
When viewed from above, winds spiral into a low-pressure center in a counter-clockwise rotation in the Northern Hemisphere. A low-pressure system is represented as a big, red L.
What is a weather front?
What is a weather front?
A front is a boundary between two different air masses, resulting in stormy weather.
A front usually is a line of separation between warm and cold air masses.
Cold Front
Cold Front
A cold front is a boundary between two air masses, one cold and the other warm, moving so that the colder air replaces the warmer air.
A cold front is represented as a blue line with the teeth pointing toward the direction of movement.
Cold fronts are associated with low pressure systems and can be very stormy.
Warm Front
Warm Front
A warm front is a boundary between two air masses, one cool and the other warm, moving so that the warmer air replaces the cooler air.
A warm front is represented as a red line with half- circles pointing toward the direction of movement.
Warm fronts are associated with high pressure systems. Warm fronts bring steady rainfall.
Relative humidity is the ratio of water vapor contained in the air compared to the maximum amount of moisture that the air can hold at that specific temperature and pressure.
Humans are very sensitive to humidity, as the skin relies on the air to get rid of moisture.
The process of sweating is your body's attempt to keep cool and maintain its current temperature. If the air is at 100-percent relative humidity, sweat will not evaporate into the air. As a result, we feel much hotter than the actual temperature when the relative humidity is high.
If the relative humidity is low, we can feel much cooler than the actual temperature because our sweat evaporates easily, cooling us off.
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