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If the weather is fair after the barometer rises, it will not last.
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It is wet and there is a sudden rise in the barometric pressure, it will not be nice for very long outside.
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In England (where these rules took place) the barometer will rise the most for north and east winds.
If the barometer is unsettled or unsteady: •
If the barometer is unsteady, you can expect unsettled weather.
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If the barometer says it is rainy and rises to the middle, you can expect a short period of good weather.
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If the barometer says good weather and it falls to say changing weather, you can expect bad weather.
So, in most cases a rising or high barometric pressure means the weather will be without precipitation, while a low barometric pressure indicates rain.
WIND FLOW Let's try to put together a better picture of air movement around the earth. You know that warm air rises, so it makes sense that when it does this you will see a low-pressure system on the ground. The air has risen so the pressure near the ground decreases. Like any system of gases, a low-pressure system is ripe for the movement of air around it to be sucked into the low-pressure. This horizontal movement of air is called advection. On the other hand, cool air will fall creating a high pressure zone near the ground. Air in the atmosphere will always flow from an area of high pressure to low-pressure. If you think about it on a molecular basis, it makes sense. High pressure areas mean lots of molecules or molecules with higher kinetic energy; these will naturally travel to low pressure areas with fewer molecules at a lower kinetic energy. Figure 22 shows you how complex it can get when you consider that air masses are moving all over our globe:
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