Why should you expect rain when the barometric pressure drops?

Answer 1

When the pressure drops, apart from the normal diurnal fluctuations, it usually means that a front, trough or low pressure system is approaching. So your chances of getting precipitation (rainfall) increases. This is a generalization though. There are many more factors to consider.

Answer 2

When the barometric pressure drops, it is reporting what is called a "low pressure zone." That term indicates that air will be coming into the region, rather than going out. Air moves from high pressure zones to low pressure zones. Hot air takes up more room, thus creates more pressure than cold air. Warm, moist air will drift into the zone, but it will not be able to hang on to its moisture when the pressure and temperature drop. The miniscule droplets of moisture will begin to fall, bumping into and joning other droplets along the way. When enough of these have formed, they will become too heavy to remain in the air, and will fall toward the earth as rain. Toward the earth is the correct term, because not all rain actually reaches the ground.

Answer 3

If air rises over a particular place(usually warm air rises as it is ligther than cold air),pressure drops and low pressure area is created there.This rising air gets cooler and cooler as it goes up and at a particular height,if it contains enough water vapour,condensation of water vapour into water droplets takes place.These water droplets form clouds from which we get rain.So if the barometric pressure drops it indicates that low pressure area is forming over there and the rising air in this area cools down throwing out the water vapour as water droplets causing the rain.

Answer 4

High pressure more blankets, blankets of oxygen. Low pressure is the hydrogen. Water is a 2:1 ratio, hydrogen is lighter than air, remember the Hindenberg. Lows & highs attempt equalizing which brings currents and winds. How large the difference causes how strong the currents. Now those hydrogen & oxygen molecules start combining and water vapors create in the atmosphere. How much hydrogen is airborne and concentrated will give you your amount of moisture in the air.

Answer 5

Basically because air saturated with water is heavier and exerts more pressure outward. Due to diffusion,molecules of a higher concentration will disperse to areas of lower concentration,The denser air will move towards areas of lower barometric pressure bringing with it a storm.