You’ve seen the blue letter “H” on weather maps indicating that a high pressure zone is on its way in, but do you know what weather associated with high pressure is like? There are actually several types of weather that can result when this weather terminology is used, depending on the origin of the high pressure zone and the season during which it occurs. Here’s a look at what you might expect if a high pressure system is moving in.
- Warm conditions: A high pressure center in the mid and upper-levels of the atmosphere tends to produce warm, clear conditions.
- Cold conditions: A high pressure center in the lower levels of the atmosphere and at the surface in the winter usually brings cold temperatures, but not stormy conditions.
- Clear skies: The column of air within a high pressure zone moves downward, which makes it difficult for clouds to grow. This tends to clear the clouds from the sky creating this type of weather associated with high pressure.
- Dry air: Sinking air within a high pressure zone tends to warm up and dry out, thus decreasing the chances of precipitation.
- Slow, clockwise winds: The Coriolis effect is responsible for this weather associated with high pressure. (In the Southern Hemisphere, high pressure zones create slow, counterclockwise winds.)
- Reduced air quality: Since wind speeds tend to drop in high pressure zones, pollution can build up. Higher temperatures allow for chemical reactions in the air to take place. Plus, the lack of clouds and warmer weather make the perfect conditions for smog or ground-level ozone.
- Clear conditions followed by stormy weather: An abrupt fall in pressure may indicate that the nice weather associated with a high pressure zone will leave as quickly as it came, since a stormy low pressure zone may be following close behind.
- Clear conditions lasting for days: A gradual rise in pressure usually indicates that nice weather can be expected for the next several days.
As you can see, weather associated with high pressure is generally mild and comfortable (except in the wintertime), which is why high pressure systems are often called “fair weather systems.” Therefore, if barometric pressure is rising, you can expect fair weather, few clouds, calm winds, and possibly higher concentrations of pollution.
Now that you know what weather associated with high pressure is like, you can get a better idea of what is headed your way. For a simple, beautiful way to keep tabs on the weather, download the WeatherCaster App for your iPad today.