Question: @ Victoria how do meteoroligosts find out the weather forecast

Ciarán O'Brien answered on 13 Nov 2014:

Meteorologists make models of the weather to predict what it will do next. They do that by taking loads of measurements in the atmosphere, from the ground to miles high in the sky. they’d measure things like temperature, wind speed and direction, humidity, air pressure, sunlight, rainfall and more.

Once they’ve taken all these measurements they can construct a model (usually on a computer) of what the weather has been doing, and use all its past movements then to figure out what’s going to happen next. They figured out early on that wind is due to areas where the air pressure is high (usually because it got warmed by sunlight and expanded) moving to where the pressure is lower. They can see what ground the air is moving over and work out if it will evaporate water as it passes to become full of water vapor which might end up as rain further on.

It’s a lot tricker than that in practice. Wind direction is affected by the earth spinning on its axis, clouds will affect how much sunlight gets to the ground, and smog and other air pollution from humans can seriously affect local weather. And the weather itself is so complicated that even with all those measurements, meteorology forecasts are not accurate enough to last more than a few days.