When checking the weather what does the pressure tell you?
In: 503
Usually, the change in pressure is the key (going down=bad weather and going up means decent weather). As a general thing, high pressure means air is descending from high up, so is dry (can’t hold much moisture at the colder temperatures of the higher atmosphere), whereas low pressure means the air is rising, so it usually fairly humid and water will condense as it cools, meaning clouds will form, and rain will happen.
Also, low pressure tends to be the front, the zone of contact between two zones of high pressure. The air coming down and spreading out from a high pressure zone runs into air from another zone doing the same general thing from somewhere else, and there is no room, so some of the air MUST rise (meaning low pressure), and rain tends to happen.
A lot of weather tends to work by large blobs of air moving across the face of the earth. Nastier weather is found where separate blobs come into contact and have a “battle” of sorts for the space. Usually, the battle involves warm air on one side and cool air on the other, and depending on which side is “winning”‘ it will be either a cold front, or a warm front.
Sometimes, like with tropical storms, so much heat energy is coming from the warm ocean below that the air is rising and a big zone of low pressure develops, perhaps becoming a hurricane. These are not being caused by war between two blobs of air (frontal systems), they form because the earth surface is too warm and makes the air rise. They weaken and eventually die when they go over land and the heat from below is less powerful, slowing the upward movement of near-surface air. Also dry out because air from land is dryer than air from ocean.
Latest Answers